Co-reporter:Guohui Li, Avinav G. Nandgaonkar, Qingqing Wang, Jinning Zhang, Wendy E. Krause, Qufu Wei, Lucian A. Lucia
Journal of Membrane Science 2017 Volume 525() pp:89-98
Publication Date(Web):1 March 2017
DOI:10.1016/j.memsci.2016.10.033
•BC was chemically oxidized to immobilize TiO2 and covalently crosslink laccase.•Immobilized laccase showed better pH, temperature stability, and reusability.•Membrane showed combined photocatalytic and biocatalytic degradation of textile dye.Bacterial cellulose (BC) was prepared by the fermentation of Komagataeibacter xylinus. Subsequently, through site-directed surface oxidation chemistry, the hydroxyl groups of BC were successfully oxidized into aldehyde groups that served as anchors for covalent immobilization of laccase (Lac) to the newly developed oxidized BC (OBC) membrane. TiO2 was additionally co-immobilized to OBC to produce a novel material in which dye degradation was carried out under specific conditions. Atomic Force Microscopy (AFM) and Scanning Electron Microscope (SEM) confirmed the installation of both TiO2 and laccase on the surface of OBC nanofiber membrane. The optimum pH, temperature, thermal stability, operational stability of the OBC/Lac and OBC/TiO2-Lac membrane were also studied in detail. In addition, the effect of the temperature and pH on dye degradation was also investigated. The results showed that the oxidation process successfully introduced aldehyde groups onto the BC (FT-IR), and also improved the stability of the immobilized laccase. Compared with free laccase, the optimum pH of immobilized laccase shifted to lower pH, while the optimum temperature decreased from 55 °C to 50 °C. The dye degradation experiments showed that the optimum pH for dye degradation was 5.0–6.0, while the optimum temperature was ~40 °C. Under UV illumination, the dye degradation efficiency was significantly improved. Therefore, functionalized composite bacterial cellulose nanofiber membranes with a combined bio- and photo- catalytic property are a potentially valid approach for industrial textile dye degradation.
Co-reporter:Guohui Li;Avinav G. Nandgaonkar;Youssef Habibi;Wendy E. Krause;Lucian A. Lucia
RSC Advances (2011-Present) 2017 vol. 7(Issue 23) pp:13678-13688
Publication Date(Web):2017/02/28
DOI:10.1039/C6RA26049G
Bacterial cellulose (BC) nanofibers secreted by Komagataeibacter xylinus 10245 were applied alone or in combination with chitosan to prepare highly aligned and porous scaffolds through a combined liquid nitrogen-initiated ice “templating” and freeze-drying process. Their morphology and physical properties were controlled by adjusting the concentration of chitosan over a range of 1, 1.5, and 2% (wt%) and analyzed by Scanning Electron Microscopy (SEM), Brunauer–Emmett–Teller (BET), and X-ray diffraction methods. The SEM images confirmed a distribution of fibrils vectorially aligned in the freezing axis direction, while chitosan contributed to the development of a dense network, superior mechanical properties, and biomedical relevance of the final scaffolds. It was found that as the chitosan concentration increased, the crystallinity index decreased from 89% to 79% likely because of strong intermolecular bonding. However, the scaffolds containing chitosan demonstrated excellent shape recovery and structural stability after compressive tests and may act as excellent scaffolds for potential cartilage tissue engineering applications.
Co-reporter:Yibing Cai, Xuebin Hou, Weiwei Wang, Mengmeng Liu, Junhao Zhang, Hui Qiao, Fenglin Huang, Qufu Wei
Thermochimica Acta 2017 Volume 653(Volume 653) pp:
Publication Date(Web):10 July 2017
DOI:10.1016/j.tca.2017.03.027
•Form-stable PCMs were made of CMS eutectics and CA phase inversion membrane.•Addition of SiO2 increased surface roughness and specific surface area of membrane.•The CA-SiO2 membrane had high CMS incorporation capacity with ∼80.3 wt.%.•Fabricated form-stable PCMs had good thermal energy storage/retrieval property.•The resulting form-stable PCMs demonstrated great temperature regulation ability.The innovative form-stable phase change materials (PCMs) were fabricated by incorporating capric-myristic-stearic acid (CMS) ternary eutectic mixture with cellulose acetate (CA) phase inversion membrane. CMS as model PCM, with melting point near ambient temperature as the temperature range was most valuable in practice. Effects of different SiO2 amounts on surface features, structural morphology and absorption capacity of CA membrane were investigated. The SiO2 nanoparticles created porous structure and increased CMS incorporation capability of CA membrane, the maximum absorption capacity of CA-SiO2 membrane was ∼80.3 wt.%. The enthalpies of melting of form-stable PCMs were 76.6 kJ/kg for CA membrane and 99.8 kJ/kg for CA-SiO2 membrane, respectively. The SiO2 nanoparticles increased remarkably thermal stability property of form-stable PCMs. As compared to CA-SiO2 membrane, the control temperature time of CMS/CA-SiO2 form-stable PCMs was increased by ∼46.8%. The developed form-stable PCMs demonstrated good thermal storage/retrieval property and thermal insulation capability.
Co-reporter:Pengfei Lv, Yixin Yao, Dawei Li, Huimin Zhou, Muhammad Awais Naeem, Quan Feng, Jieyu Huang, Yibing Cai, Qufu Wei
Carbohydrate Polymers 2017 Volume 172(Volume 172) pp:
Publication Date(Web):15 September 2017
DOI:10.1016/j.carbpol.2017.04.086
•As-prepared N-CDs shows excellent optic properties.•As-prepared BC/N-CDs were applied to the detection of Fe3+ in aqueous solution via sustainable one-step method of biosynthesis.•This fluorescence sensor shows high sensitive response in acceptable range of 0.5–600 μM and ultralow detection limit of 84 nM.•This work expands application scopes of both bacterial cellulose and fluorescence materials.Nitrogen-doped carbon dots (N-CDs) were synthesized through a facile hydrothermal method using citric acid (CA) and ethanediamine (EDA) as precursors. A green and simple fluorescence biosensor was obtained by biosynthesis of bacterial cellulose (BC)/N-CDs. As-prepared N-CDs with rich functional groups exhibited a blue emission under the excitation wavelength of 350 nm. Biosynthesis of BC/N-CDs was analyzed by Digital photos, Fourier Transform Infrared (FTIR) and Transmission Electron Microscopy (TEM). The results indicated that N-CDs were successfully anchored on BC. As-prepared BC/N-CDs were applied to the detection of Fe3+ in aqueous solution. Spectroscopic data revealed that, fluorescence materials prepared presented an sensitive response to Fe3+ in acceptable range of 0.5–600 μM and ultralow detection limit of 84 nM as a fluorescence sensor. Furthermore, the results also indicate that a novel BC/N-CDs composite has great potential for the detection of Fe3+ ions based on membrane fluorescence materials.
Co-reporter:Zengyuan Pang;Qingxin Nie;Anfang Wei;Jie Yang
Journal of Materials Science 2017 Volume 52( Issue 2) pp:686-695
Publication Date(Web):2017 January
DOI:10.1007/s10853-016-0362-1
Indium oxide/polyaniline (In2O3/PANI) composite nanofibers with the solid or hollow structure of In2O3 were successfully synthesized via a facile and efficient combined method of electrospinning, high-temperature calcination, and in situ polymerization. Various techniques, including scanning electron microscopy, Brunauer–Emmett–Teller, Fourier transform infrared, transmission electron microscopy, and X-ray diffraction, were employed to acquire the morphological, structural, and crystalline information of the prepared samples. The gas sensing performances of the as-obtained composite nanofibers were investigated by a home-made gas sensing test system at room temperature. All the results demonstrated that both solid and hollow In2O3/PANI composite nanofibers had higher response values than those of pure PANI sensor. In addition, the ammonia sensing properties of hollow In2O3/PANI composite nanofibers were much better than that of the solid ones. Furthermore, hollow In2O3/PANI composite nanofibers also showed ideal repeatability and selectivity due to their more and different types of P-N heterojunctions.
Co-reporter:Xvdan Lv, Guohui Li, Dawei Li, Fenglin Huang, Wenting Liu, Qufu Wei
Journal of Physics and Chemistry of Solids 2017 Volume 110(Volume 110) pp:
Publication Date(Web):1 November 2017
DOI:10.1016/j.jpcs.2017.06.017
•High capacitance N- and O-enriched activated carbon was obtained by pyrolysis and active polyaniline coated BC.•Low cost, environmental friendly materials were used to prepare flexible membrane supercapacitor.•A new method to prepare no-binder, integral electrodes-separator all-solid-state flexible supercapacitor was achieved.•The 3D network, multilayers structure of bacterial cellulose membrane was fully utilized.•The flexible supercapacitor showed low solution resistances at 1 mol PVA/H2SO4 electrolyte.Bacterial cellulose (BC) with unique three dimensional multilayer network structure and excellent mechanical strength is used for the substrate of the all-solid-state flexible supercapacitor. The technique was realized by in-situ depositing conductive polymer polyaniline (PANI) on BC, through both peeling off one side of the multilayer PANI/BC composition film and filtrating KOH activated pyrolysis PANI/BC (KPBC) obtained N- and O-enriched carbon powders on the peeling side. The flexible integral electrode-separator supercapacitor device was about 15 μm, which exhibited the well bending and stretching performance. The film supercapacitor also showed excellent cycle life with maximum 28.3 F cm−3 volumetric capacitance, and retains 100% over 2500 charge/discharge cycles at the 0.1 A g−1 current density. In addition, the flexible supercapacitor only indicated 2.48 Ω solution resistances (Rs) at 1 mol PVA/H2SO4 electrolyte. This flexible film supercapacitor has great potential in wearable devices.Download high-res image (205KB)Download full-size image
Co-reporter:Huimin Zhou, Muhammad Awais Naeem, Pengfei Lv, Jin Zhang, Zengyuan Pang, Lei Luo, Yibing Cai, Xin Xia, Qufu Wei
Journal of Alloys and Compounds 2017 Volume 711(Volume 711) pp:
Publication Date(Web):15 July 2017
DOI:10.1016/j.jallcom.2017.04.017
•The mechanism for forming different pore distribution is proposed.•Evolution of pore distribution relies on synergism between precursors.•Multichannel pores within the nanofibers possesses high capacity stability.Carbon-coated SnO2 composite nanofibers has been considered as an efficient way to alleviate the enormous volume change problem of tin-based anodes for lithium ion batteries (LIBs). Herein, porous carbon/SnO2 nanofibers were prepared via single-needle electrospinning which was followed by carbonization treatment. The procedure involved two categories of precursors of SnO2, stannic chloride pentahydrate and stannic acetate, whereas former was fully dissolved while later was partially dissolved in solvent, leading to different pore distribution in cooperating with thermal decomposition of polymethyl methacrylate. The pores generated from stannic chloride pentahydrate/polymethyl methacrylate system were randomly distributed on the surface of nanofibers. In the case of stannic acetate/polymethyl methacrylate derived composites, the thermolysis of polymer left multichannels within the nanofibers coupled with SnO2 nanoparticles. Galvanostatic charge/discharge was carried out to evaluate them as anode materials for LIBs. It was found that multichannel carbon/SnO2 nanofibers with large specific surface area (34.97 m2/g) achieved better rate capability and stable capacity retention of 89.9% after 50 cycles. The longitudinally aligned pores facilitated lithium diffusion and transference, which avoided nonuniform deposition and separation of lithium ions, thereby further enhancing the stability during the discharge/charge process.Compared to pores formed on the outer surface, the carbon/SnO2 nanofibers anodes with multichannel pore structure are promising to achieve stable electrochemical performance.Download high-res image (185KB)Download full-size image
Co-reporter:Yibing Cai;Xiaofei Song;Mengmeng Liu
Journal of Thermal Analysis and Calorimetry 2017 Volume 128( Issue 2) pp:661-673
Publication Date(Web):2017 May
DOI:10.1007/s10973-016-5937-1
The objective of this study was to explore an innovative type of form-stable phase-change materials (PCMs) with flexible cellulose acetate (CA) nano-fibrous felts (nano-felts) absorbed with capric–myristic–stearic acid ternary eutectic mixture for thermal energy storage/retrieval. Capric–myristic–stearic acid (CMS) ternary eutectic mixture as model PCM was firstly prepared. The developed CA nano-felts as supporting material was mechanically flexible and was made from CA/polyvinylpyrrolidone (PVP) precursor composite nanofibers followed by removal of PVP components. The effects of original mass ratio of CA/PVP on absorption capacities of CA nano-felts were studied. The modified CA nano-felts with groove/porous structure and rough surfaces were capable of absorbing a large amount of PCMs. The morphological structures, as well as the properties of thermal energy storage, thermal stability and reliability, and thermal insulation of composite PCMs were characterized by scanning electron microscopy, differential scanning calorimetry, and thermal performance measurement, respectively. The results showed that CMS eutectic was absorbed in and/or supported by modified CA nano-felts. The heat enthalpy values of composite PCMs have slightly decreased in comparison with the corresponding theoretical values. The composite PCMs demonstrated good thermal stability and reliability after thermal cycles. The composite PCMs had high thermal insulation capability for temperature regulation.
Co-reporter:Lei Luo, Wenzheng Xu, Zhaokang Xia, Yaqian Fei, Jiadeng Zhu, Chen Chen, Yao Lu, Qufu Wei, Hui Qiao, Xiangwu Zhang
Ceramics International 2016 Volume 42(Issue 9) pp:10826-10832
Publication Date(Web):July 2016
DOI:10.1016/j.ceramint.2016.03.211
Abstract
ZnO–SnO2 composite nanofibers with different structures were synthesized by a simple electrospinning approach with subsequent calcination at three different temperatures using polyacrylonitrile as the polymer precursor. The electrochemical performance of the composites for use as anode materials in lithium-ion batteries were investigated. It was found that the ZnO–SnO2 composite nanofibers calcined at 700 °C showed excellent lithium storage properties in terms of cycling stability and rate capability, compared to those calcined at 800 and 900 °C, respectively. ZnO–SnO2 composite nanofibers calcined at 700 °C not only delivered high initial discharge and charge capacities of 1450 and 1101 mAh g−1, respectively, with a 75.9% coulombic efficiency, but also maintained a high reversible capacity of 560 mAh g−1 at a current density of 0.1 A g−1 after 100 cycles. Additionally, a high reversible capacity of 591 mAh g−1 was obtained when the current density returned to 0.1 A g−1 after 50 cycling at a high current density of 2 A g−1. The superior electrochemical performance of ZnO–SnO2 composite nanofibers can be attributed to the unique nanofibrous structure, the smaller particle size and smaller fiber diameter as well as the porous structure and synergistic effect between ZnO and SnO2.
Co-reporter:Jie Yang, Dawei Li, Jiapeng Fu, Fenglin Huang, Qufu Wei
Journal of Electroanalytical Chemistry 2016 Volume 766() pp:16-23
Publication Date(Web):1 April 2016
DOI:10.1016/j.jelechem.2016.01.030
•TiO2/CuCNFs was prepared in this work.•A novel laccase biosensor based on TiO2/CuCNFs was applied in hydroquinone detection.•The linear range of the prepared biosensor is 1 μM to 89.8 μM.A novel biosensor was prepared on the basis of laccase, Nafion and TiO2 loaded copper and carbon composite nanofibers (TiO2/CuCNFs) obtained through electrospinning, carbonization and solvothermal treatment. The introduction of TiO2 apparently improved the electrocatalysis of the biosensor for the detection of hydroquinone. In addition, cyclic voltammetry analysis of the biosensor showed a pair of well-defined redox peaks, and revealed that the electrochemical behavior of laccase was a surface-controlled process. Chronoamperometry technique was also employed to investigate the biosensor. The results displayed a linear range from 1 μM to 89.8 μM, detection limit of 3.65 μM (S/N = 3), a sensitivity of 24.6 μA/mM, a high selectivity, as well as good repeatability and stability. The biosensor showed great promise in hydroquinone monitoring.
Co-reporter:Guohui Li, Avinav G. Nandgaonkar, Keyu Lu, Wendy E. Krause, Lucian A. Lucia and Qufu Wei
RSC Advances 2016 vol. 6(Issue 47) pp:41420-41427
Publication Date(Web):20 Apr 2016
DOI:10.1039/C6RA00220J
The engineering of supports for enzyme immobilization while retaining competent functionality is nontrivial. We attempted to enhance the removal efficiency of organics by adopting a relatively novel approach involving a synergy from the adsorption capabilities of a support incorporated with organically modified montmorillonite (O-MMT) and catalytic properties of immobilized laccase. Electrospun polyacrylonitrile (PAN)/O-MMT membranes after alkaline hydrolysis and carboxyl activation were chosen as the support system for laccase immobilization. A confocal laser scanning microscope confirmed a uniform enzyme distribution along with the fibers' longitudinal surface. After enzyme immobilization, the optimum pH shifted from 3 to 3.5, while the optimum temperature remain unchanged at 50 °C. Its stability was preserved despite a large fluctuation in pH (50% of its initial activity retained over the pH range 2–6) and temperature (more than 80% of its initial activity retained over 30–70 °C). Compared to free laccase, the thermal stability of the immobilized laccase was improved after being under 30 °C and 50 °C for 8 h. The operational stability was 68% of the initial one after 10 times repeated usage, while also demonstrating 80% storage stability of the initial activity even after two months. The immobilized laccase showed a high removal efficiency of crystal violet at an optimum pH of 5 and temperature ∼40 °C as well as an initial substrate concentration of 100 mg L−1. Compared with that of the individual support and the free laccase, the removal efficiency by an immobilized enzyme is far higher to confirm a synergy in the immobilized enzyme and support system.
Co-reporter:Jinning Zhang;Mingyu Song;Xiaoyu Wang;Jieru Wu;Zhanping Yang;Jianhua Cao;Yun Chen
Journal of Applied Polymer Science 2016 Volume 133( Issue 33) pp:
Publication Date(Web):
DOI:10.1002/app.43818
ABSTRACT
Four types of fibrous membranes based on cellulose acetate (CA)—CA membranes with nonporous fibers, CA/organic montmorillonite (O-MMT) membranes with nonporous fibers, CA membranes with porous fibers, and CA/O-MMT membranes with porous fibers—were prepared by electrospinning, and then, they were used for enzyme immobilization. The surface morphologies of the composite fibrous membranes were investigated with scanning electron microscopy and transmission electron microscopy. The optimum pH was 3.5 for all of the immobilized enzymes, and the optimum temperature was 50 °C. Compared with the free enzyme, the immobilized enzyme showed better stability for pH and temperature changes. Moreover, the addition of O-MMT and the pores on the fibers improved the storage stability and the operational stability. Among the four kinds of fibrous membranes, the CA/O-MMT membranes with porous fibers showed the best stability for the immobilized enzymes. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43818.
Co-reporter:Guohui Li, Kaiyue Sun, Dawei Li, Pengfei Lv, Qingqing Wang, Fenglin Huang, Qufu Wei
Colloids and Surfaces A: Physicochemical and Engineering Aspects 2016 Volume 509() pp:408-414
Publication Date(Web):20 November 2016
DOI:10.1016/j.colsurfa.2016.09.028
•A composite containing gold nanoparticles were prepared by combining bacterial cellulose and one–step reduction method.•It is noticeable that the laccase biosensor showed a high electrochemical response and electrocatalysis toward hydroquinone.•The novel biosensor will offer a simple and high efficient method for detecting hydroquinone compounds in environment.Bacterial cellulose-gold nanoparticles (BC-AuNPs) hybrid nanofibers were synthesized by in-situ chemical reduction. The obtained BC-AuNPs nanofibers were characterized by a series of analytical techniques. The results revealed that gold nanoparticles (AuNPs) were successfully deposited on the surfaces of bacterial cellulose nanofibers. Then, the as-prepared BC-AuNPs hybrid nanofibers were attached onto the electrode surface followed by adding a certain amount of laccase (Lac) and Nafion to construct novel a biosensing platform. The prepared electrochemical biosensor was employed to detect hydroquinone. The sensor showed excellent electrocatalysis towards dopamine with low detection limit (5.71 nM), and wide linear range (30–100 nM). Moreover, the biosensor also showed good repeatability, reproducibility, selectivity and stability and was successfully used in the detection of hydroquinone in lake water samples, thus providing a promising method for hydroquinone detection in water environments.
Co-reporter:Christopher Narh;Guohui Li;Qingqing Wang;Fenglin Huang
Colloid and Polymer Science 2016 Volume 294( Issue 9) pp:1483-1494
Publication Date(Web):2016 September
DOI:10.1007/s00396-016-3911-x
The exploration of the potentials of peptide in drug delivery has led to numerous studies in peptide synthesis involving different protocols depending on the expected final products. In this study, we explored the self-assembling behavior of sulfanilic acid by reacting it with two hydrophobic amino acids namely valine and alanine using the linear polypeptide synthesis protocol. The reaction consequently resulted in bonding together of linear fibrous structures. Results on scanning electron microscope revealed that the individual fibers separated upon the introduction of aniline, an increased length and further observation showing that the fibers were altered into four different structures. Results on X-ray diffraction revealed that amide C-N bond in a peptide was found to be shorter than the C-N bond in a simple amine and residue backbone dihedral angles of around −60° and −45° in α-helix formation, while the dramatic rotation around the N2_C2_ bond resulted in tube. On the other hand, results on atomic force microscopy (AFM) revealed a fairly rough surface, while differential scanning calorimeter (DSC) results indicated that, at Tg (85 °C), the fibers underwent endothermic decomposition of about −2.5 mg and experienced an exothermic recrystallization at 125 °C. Results on thermogravimetric analysis (TGA) confirmed that the fiber was stable at 180 °C.
Co-reporter:Pengfei Lv;Quan Feng;Qingqing Wang;Dawei Li;Jianbo Zhou
Fibers and Polymers 2016 Volume 17( Issue 11) pp:1858-1865
Publication Date(Web):2016 November
DOI:10.1007/s12221-016-6337-7
In this study, electrically conducting composite membranes were prepared by incorporating carboxylic multi-walled carbon nanotubes (c-MWCNTs) into Bacterial Cellulose (BC) pellicles. The biocathode and bioanode were prepared by a simple method of adsorption. An enzyme biological fuel cell (EBFC) composed of a biocathode and an enzymatic bioanode were developed and tested. The materials was characterised by field emission scanning electron microscope (FESEM), Fourier Transform Infrared (FTIR) Spectroscopy and Thermogravimetric analysis (TGA). The results showed that the presence of c-MWCNTs on BC was certified, on which c-MWCNTs loading was calculated as 30.02/100 g. The BC/c-MWCNTs/Lac composite membranes was characterized by cyclic voltammetry (CV). An EBFC was characterized by linear sweep voltammetry (LSV). The results showed EBFC exhibited excellent performance with the largest open circuit voltage (0.76 V) and a maximum power density value (55 uW/cm3). Additionally, the cell also exhibited acceptable stability over the recording of 30 days. BC was considered to be suitable for advanced applications such as an enzymatic carrier of biological fuel cells.
Co-reporter:Jianbo Zhou;Qingqing Wang;Hangyi Lu;Quan Zhang;Pengfei Lv
Fibers and Polymers 2016 Volume 17( Issue 11) pp:1835-1841
Publication Date(Web):2016 November
DOI:10.1007/s12221-016-6716-0
Biocompatible polyvinyl alcohol (PVA)-styrylpyridinium (SbQ)/β-cyclodextrin (β-CD) composite nanofibers were obtained by electrospinning in this study. PVA-SbQ was used as the foundation polymer as well as crosslinking agent, β-CD was incorporated to achieve expected properties such as improved mechanical properties and thermal stability. The Fourier transform infrared spectroscopy (FTIR) spectra confirmed the existence of β-CD, and the morphologies and average fiber diameters of the electrospun composite nanofibers were also analyzed by SEM. X-ray diffraction patterns (XRD) of PVA-SbQ/β-CD composite nanofibers revealed that the inclusion of β-CD in the nanofibers affected the ordered phase of PVA. Besides, the thermal analyses revealed the improvement in the thermal properties for PVA-SbQ/β-CD composite nanofibers. It was found that the crosslinked composite nanofibers showed a clear higher tensile strength (TS) as well as a greater elongation at break (EB). Eventually, antifungal drug griseofulvin (GSV) has been loaded into the composite nanofibers by formation of its inclusion complex with β-CD in aqueous solution, ultraviolet light (UV-Vis) spectral analysis showed that the drug-loading nanofibers had certain sustained release effect.
Co-reporter:Jinning Zhang;Mingyu Song;Dawei Li;Zhanping Yang;Jianhua Cao
Fibers and Polymers 2016 Volume 17( Issue 9) pp:1414-1420
Publication Date(Web):2016 September
DOI:10.1007/s12221-016-6581-x
Polyacrylonitrile (PAN) oriented nanofibers were produced by homemade needleless electrospinning device. Spiral coils were adopted to replace the traditional spinning needles in this equipment. The tracks of multi-jets were controlled by adjusting the microcurrent during the eletrospinning process. The microcurrent value and the motion track of the spinning jet during the spinning process were observed, the fiber morphology and the mechanical properties of fiber membranes were measured. The results revealed that the average diameters of the electrospun fibers were increased from 490 nm to 740 nm. with the addition of organic salt. Meanwhile, the self-clustering phenomenon was obviously observed, and the mechanical properties of obtained fibers were also altered, the tensile strength was improved from 3.63 MPa to 23.90 MPa, while the strain decreased from 74.6 % to 27.1 %.
Co-reporter:Yuyu Qiu, Liying Qiu, Jing Cui, Qufu Wei
Materials Science and Engineering: C 2016 Volume 59() pp:303-309
Publication Date(Web):1 February 2016
DOI:10.1016/j.msec.2015.10.016
•BC and BC-Vac membranes were produced to achieve desirable properties.•BC and BC-Vac membranes could be a good carrier for cell growth.•BC-Vac membranes have potential application for wound healing.Bacterial cellulose (BC) and bacterial cellulose-vaccarin (BC-Vac) membranes were successfully produced in large scale. BC was synthesized by Gluconacetobacter xylinum. BC-Vac membranes were prepared by immersing BC in vaccarin solution. The surface morphologies of BC and BC-Vac membranes were examined by a scanning electron microscope (SEM) and an atomic force microscopy (AFM). The images showed that BC-Vac exhibited the characteristic 3D nanofibrillar network of BC matrix but there was adhesion between fibers. The mechanical properties of BC and BC-Vac membranes were evaluated and the results indicated that the adding of drug vaccarin into the BC membranes increased the malleability indicated by the increment in elongation at break compared with BC. Fourier transform infrared spectroscopy (FTIR) analysis was conducted to confirm the incorporation of vaccarin in BC-Vac and investigate the hydroxyl interactions between BC and drug vaccarin. Cell viability and cell attachment studies demonstrated that BC and BC-Vac membranes had no cytotoxicity and could be a good carrier for cell growth. The wound healing performance was examined in vivo by rat skin models. Histological observations revealed that wounds treated with BC-Vac epithelialized and regenerated faster than treated with BC. Therefore, BC-Vac was considered as a potential candidate for wound dressing materials.
Co-reporter:Zengyuan Pang, Zhanping Yang, Yun Chen, Jinning Zhang, Qingqing Wang, Fenglin Huang, Qufu Wei
Colloids and Surfaces A: Physicochemical and Engineering Aspects 2016 Volume 494() pp:248-255
Publication Date(Web):5 April 2016
DOI:10.1016/j.colsurfa.2016.01.024
•We report a facile approach to prepare cellulose/TiO2/PANI composite nanofibers that involves P–N heterojunctions.•The response values and sensitivity of cellulose/TiO2/PANI were much higher than those of cellulose/PANI composite nanofibers.•Enhanced sensing was obtained due to the P–N heterojunctions whose depletion layer would be widened when the sensor was exposed to ammonia.We report a facile approach to prepare cellulose/titanium dioxide/polyaniline (cellulose/TiO2/PANI) composite nanofibers that involves P–N heterojunctions at the interface of p-type PANI and n-type TiO2. This work found that the P–N heterojunctions could improve ammonia sensing properties of the prepared nanofibers. Electrospun cellulose acetate nanofibers were deacetylated to prepare regenerated cellulose nanofibers, and then the obtained cellulose nanofibers were immersed into TiO2 sol to adsorb TiO2 nanoparticles onto the surface of them to fabricate cellulose/TiO2 composite nanofibers. In-situ polymerization of aniline was utilized to deposit PANI on the surface of cellulose/TiO2 composite nanofibers. The gas sensing properties of the prepared nanofibers were evaluated by a home-made test system. The cellulose/TiO2/PANI and cellulose/PANI composite nanofibers were exposed to 10, 30, 50, 100, 150, 200 and 250 ppm ammonia vapor at room temperature, respectively. It was found that the response values and sensitivity of cellulose/TiO2/PANI were much higher than those of cellulose/PANI composite nanofibers. Enhanced sensing was obtained by cellulose/TiO2/PANI due to the P–N heterojunctions whose depletion layer would be widened when the composite nanofibers were exposed to ammonia, resulting in their resistance increased dramatically.
Co-reporter:Xue Zong, Yibing Cai, Guiyan Sun, Yong Zhao, Fenglin Huang, Lei Song, Yuan Hu, Hao Fong, Qufu Wei
Solar Energy Materials and Solar Cells 2015 Volume 132() pp:183-190
Publication Date(Web):January 2015
DOI:10.1016/j.solmat.2014.08.030
•Form-stable PCMs consisted of electrospun SiO2 nanofibers and fatty acid eutectics.•SiO2 nanofibers had high absorption capacity on PCMs of fatty acid eutectics.•Composite PCMs exhibited high heat enthalpy for thermal energy storage/retrieval.•SiO2 nanofibers were able to improve the thermal conductivity of form-stable PCMs.Electrospun SiO2 nanofibers (in the form of overlaid mat) absorbed with fatty acid eutectics were studied to fabricate form-stable phase change materials (PCMs) for storage and retrieval of thermal energy. The SiO2 nanofibers were made via electrospinning of precursor nanofibers followed by pyrolysis, while four fatty acid eutectics of capric acid–lauric acid (CA–LA), capric acid–myristic acid (CA–MA), capric acid–palmitic acid (CA–PA), and capric acid–stearic acid (CA–SA) were studied as the model PCMs. The morphological structure, absorption capacity, thermal energy storage property, and thermal energy storage/retrieval rates of the developed form-stable composite PCMs were characterized by scanning electron microscopy, differential scanning calorimetry, and measurement of melting/freezing time. The results indicated that the electrospun SiO2 nanofibrous mats were highly porous and capable of absorbing a large amount of PCMs, and the absorption capacities of SiO2 nanofibers for the four fatty acid eutectics (i.e., CA–LA, CA–MA, CA–PA and CA–SA) were 82.0, 83.7, 84.2, and 83.1%, respectively. The experimental values of heat enthalpy for the fabricated composite PCMs were slightly lower than the corresponding theoretical values, whereas there were no appreciable changes on phase transition temperatures. In comparison with fatty acid eutectics (without supporting materials), the melting and freezing time periods of the corresponding CA–LA/SiO2, CA–MA/SiO2, CA–PA/SiO2, CA–SA/SiO2 were shortened by 28.6% and 30.8%, 20.0% and 44.4%, 62.5% and 50.0%, and 50.0% and 33.3%, respectively. This study suggested that the fabricated form-stable composite PCMs possessed appropriate phase transition temperatures and high heat enthalpy values; hence, they would have potential applications for low-temperature thermal energy storage/retrieval.Thermal energy storage property of composite PCMs.
Co-reporter:Fenglin Huang, Yunfei Xu, Bin Peng, Yangfen Su, Feng Jiang, You-Lo Hsieh, and Qufu Wei
ACS Sustainable Chemistry & Engineering 2015 Volume 3(Issue 5) pp:932
Publication Date(Web):March 25, 2015
DOI:10.1021/acssuschemeng.5b00032
This paper reports an eco-friendly approach for extracting cellulose acetate (CA) from waste cigarette filter to construct a cellulose-based membrane separator for a high-performance lithium-ion battery. A cellulose/poly(vinylidene fluoride-co-hexafluoropropylene (PVDF-HFP) nanofiber membrane was prepared by coaxial electrospinning of a cellulose acetate core and PVDF-HFP shell, then hydrolyzed by LiOH. The cellulose-core/PVD-HFP-shell fibrous membrane shows good tensile strength (34.1 MPa), high porosity (66%), excellent thermal stability (to 200 °C), and super electrolyte compatibility (355% electrolyte uptake). It has a lower interfacial resistance (98.5 Ω) and higher ionic conductivity (6.16 mS cm–1) than those of commercial separators (280.0 Ω and 0.88 mS cm–1). In addition, the rate capability (138 mAh·g–1) and cycling performance (75.4% after 100 cycles) are also superior to those of the commercial separators, demonstrating the cellulose-core fibrous membrane to be a promising separator for a high-power and more secure lithium-ion battery.Keywords: Coaxial electrospinning; Recycled cellulose; Separator;
Co-reporter:Yibing Cai, Guiyan Sun, Mengmeng Liu, Jin Zhang, Qingqing Wang, Qufu Wei
Solar Energy 2015 Volume 118() pp:87-95
Publication Date(Web):August 2015
DOI:10.1016/j.solener.2015.04.042
•CA–LA–PA eutectic mixture was fabricated as the model phase change material (PCM).•Electrospun SiO2 nanofibers were made as supporting material.•Form-stable PCM consisted of CA–LA–PA eutectic mixture and SiO2 nanofibers.•Composite PCM possessed high thermal energy storage and good thermal reliability.Through combining a eutectic mixture of capric–lauric–palmitic acid (CA–LA–PA) as phase change material (PCM) and SiO2 nanofibers as supporting material, a novel form-stable PCM based composite was fabricated and studied for thermal energy storage and retrieval. Specifically, the SiO2 nanofibers, prepared via electrospinning followed by a high temperature annealing process, were used to absorb and/or support the PCM consisted of CA–LA–PA eutectic mixture. The structure, morphology and thermal property of prepared CA–LA–PA eutectic mixture, electrospun SiO2 nanofibers and composite PCM were characterized by Fourier transfer infrared (FT-IR) spectra, Scanning electron microscopy (SEM) and Differential scanning calorimeter (DSC), respectively. The results showed the electrospun SiO2 nanofibers were successfully fabricated with high porosity which is capable of absorbing a large amount of PCM; and the CA–LA–PA was uniformly absorbed into porous framework of SiO2 nanofibers. In addition, the phase transition temperatures of CA–LA–PA eutectic mixture were lower than those of individual fatty acids. The melting and crystallization temperatures and heat enthalpies of composite PCM were 21.7 and 6.4 °C, and 100.9 and 96.5 kJ/kg, respectively; indicating that the composite PCM possessed appropriate phase transition temperatures and high latent heat. Thermal cycling test results showed that there were no noticeable variations on the phase transition temperatures and heat enthalpies after 50 thermal cycles; revealing that the prepared form-stable composite PCM is promising for thermal energy storage/retrieval due to the good thermal reliability and stability.
Co-reporter:Jiapeng Fu, Zengyuan Pang, Jie Yang, Fenglin Huang, Yibing Cai, Qufu Wei
Applied Surface Science 2015 Volume 349() pp:35-42
Publication Date(Web):15 September 2015
DOI:10.1016/j.apsusc.2015.04.215
Highlights
- •
PANI nanorods have been grown onto the surface of CMC/cellulose nanofibers for the fabrication of biosensor substrate material.
- •
The proposed laccase biosensor exhibited a low detection limit and high sensitivity in the detection of catechol.
- •
Hierarchical PANI/CMC/cellulose nanofibers are the promising material in the design of high-efficient biosensors.
Co-reporter:Xiaodong Chen, Dawei Li, Guohui Li, Lei Luo, Naseeb Ullah, Qufu Wei, Fenglin Huang
Applied Surface Science 2015 Volume 328() pp:444-452
Publication Date(Web):15 February 2015
DOI:10.1016/j.apsusc.2014.12.070
Highlights
- •
We utilized the hydrophobic protein nanofibers to fabricate a laccase-based biosensor for the first time.
- •
The composite containing gold nanoparticles was prepared by combining electrospinning and one-step reduction method, which is a novel nanomaterial.
- •
It is noticeable that the laccase biosensor showed a high electrochemical response and electrochemical activity toward catechol.
- •
The novel biosensor will offer a simple, convenient and high efficient method for detecting polyphenolic compounds in environment.
Co-reporter:Jiapeng Fu, Dawei Li, Guohui Li, Fenglin Huang, Qufu Wei
Journal of Electroanalytical Chemistry 2015 Volume 738() pp:92-99
Publication Date(Web):1 February 2015
DOI:10.1016/j.jelechem.2014.11.025
•A facile approach to produce AgNPs-CMC/cellulose composite nanofibrous mats has been developed.•Laccase biosensor based on AgNPs-CMC/cellulose composite nanofibrous mats for catechol detection was developed in this work.•The detection limit of the obtained biosensor to catechol is 1.64 μM.•The composite nanofibers could provide a new platform for other redox proteins immobilization.We report a facile approach to synthesize and immobilize silver nanoparticles (AgNPs) onto carboxymethyl cellulose (CMC)-modified electrospun cellulose nanofibers and demonstrate the potential application of as-prepared AgNPs-CMC/cellulose composite nanofibrous mats as effective biosensor substrate materials. Cellulose nanofibers were prepared by the combination of electrospinning with deacetylation. Then, CMC was adsorbed onto cellulose nanofibers to complex silver ions through the chemical binding with the free carboxyl groups of CMC for subsequent reductive formation of AgNPs. The AgNPs-CMC/cellulose nanofibers immobilized with laccase (Lac) by electrostatic interactions were used as biosensor substrate materials for catechol detection. The cyclic voltammetries revealed that the AgNPs-CMC/cellulose nanofibers was beneficial to the immobilization of Lac and facilitated the direct electron transfer between Lac and electrode. Lac/AgNPs-CMC/cellulose/glassy carbon electrode exhibited a detection limit of 1.64 μM (S/N = 3), and a wide linear range from 4.98 μM to 3.65 mM, as well as good repeatability, reproducibility, stability, and selectivity. The CMC/cellulose nanofibrous mats have great potential applications as substrate materials for different biosensors by immobilizing other different functional nanoparticles or enzyme on them.Graphical abstract
Co-reporter:Dawei Li, Guohui Li, Pengfei Lv, Naseeb Ullah, Cheng Wang, Qingqing Wang, Xiangwu Zhang and Qufu Wei
RSC Advances 2015 vol. 5(Issue 39) pp:30602-30609
Publication Date(Web):25 Mar 2015
DOI:10.1039/C5RA03310A
A combined method of electrostatic adsorption and green reduction was successfully employed to synthesize graphene-loaded carbon nanofibers (G/CNFs). The graphene nanoflakes enhanced the degree of graphitization of CNFs. A mixture containing laccase (Lac), G/CNFs and Nafion was used to fabricate a novel biosensor. The G/CNFs facilitated the direct electron transfer between Lac and the modified electrode. A pair of apparently enhanced redox peaks was observed on the modified electrode. The biosensor was investigated using square wave voltammetry, and the biosensor displayed highly efficient electrocatalysis towards catechol with a detection limit of 20 nM (S/N = 3), a sensitivity of 13.5 μA μM−1, and a linear range from 1 × 10−7 to 2.86 × 10−6 M. Moreover, this new biosensor also showed good stability and selectivity, and was employed in measuring catechol concentration in a real water environment successfully.
Co-reporter:Jing Cui;Liying Qiu;Yuyu Qiu;Qingqing Wang
Journal of Applied Polymer Science 2015 Volume 132( Issue 39) pp:
Publication Date(Web):
DOI:10.1002/app.42565
ABSTRACT
In this study, electrospun biocompatible nanofibers with random orientation were prepared by physically blending poly(vinyl alcohol)-stilbazol quaternized (PVA-SbQ) with zein in acetic acid solution for wound healing. PVA-SbQ was used as the foundation polymer as well as crosslinking agent, blended with zein to achieve desirable properties such as improved tensile strength, surface wettability, and in vitro degradable properties. Moreover, vaccarin drug was incorporated in situ into electrospun nanofibrous membranes for cell viability and cell attachment. The addition of vaccarin showed great effects on the morphology of nanofiber and enhanced cell viability and proliferation in comparison with composite nanofibers without drug. The presence of PVA-SbQ, zein, and vaccarin drug in the nanofibrous membranes exhibited good compatibility, hydrophilicity, and biocompatibility and created a moist environment to have potential application for wound healing. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42565.
Co-reporter:Hui Qiao, Lei Luo, Ke Chen, Yaqian Fei, Rongrong Cui, Qufu Wei
Electrochimica Acta 2015 160() pp: 43-49
Publication Date(Web):
DOI:10.1016/j.electacta.2015.02.012
Co-reporter:Dawei Li, Lei Luo, Zengyuan Pang, Lei Ding, Qingqing Wang, Huizhen Ke, Fenglin Huang, and Qufu Wei
ACS Applied Materials & Interfaces 2014 Volume 6(Issue 7) pp:5144
Publication Date(Web):March 7, 2014
DOI:10.1021/am500375n
A novel phenolic biosensor was prepared on the basis of a composite of polydopamine (PDA)-laccase (Lac)-nickel nanoparticle loaded carbon nanofibers (NiCNFs). First, NiCNFs were fabricated by a combination of electrospinning and a high temperature carbonization technique. Subsequently, the magnetic composite was obtained through one-pot Lac-catalyzed oxidation of dopamine (DA) in an aqueous suspension containing Lac, NiCNFs, and DA. Finally, a magnetic glass carbon electrode (MGCE) was employed to separate and immobilize the composite; the modified electrode was then denoted as PDA-Lac-NiCNFs/MGCE. Fourier transform infrared (FT-IR) spectra and cyclic voltammetry (CV) analyses revealed the NiCNFs had good biocompatibility for Lac immobilization and greatly facilitated the direct electron transfer between Lac and electrode surface. The immobilized Lac showed a pair of stable and well-defined redox peaks, and the electrochemical behavior of Lac was a surface-controlled process in pH 5.5 acetate buffer solution. The PDA-Lac-NiCNFs/MGCE for biosensing of catechol exhibited a sensitivity of 25 μA mM–1 cm–2, a detection limit of 0.69 μM (S/N = 3), and a linear range from 1 μM to 9.1 mM, as well as good selectivity and stability. Meanwhile, this novel biosensor demonstrated its promising application in detecting catechol in real water samples.Keywords: carbon nanofibers; dopamine; electrospinning; laccase; nickel nanoparticle; phenolic biosensor;
Co-reporter:Quan Feng, Yong Zhao, Anfang Wei, Changlong Li, Qufu Wei, and Hao Fong
Environmental Science & Technology 2014 Volume 48(Issue 17) pp:10390-10397
Publication Date(Web):August 5, 2014
DOI:10.1021/es501845u
In this study, a mat/membrane consisting of overlaid PVA/PA6–Cu(II) composite nanofibers was prepared via the electrospinning technique followed by coordination/chelation with Cu(II) ions; an enzyme of catalase (CAT) was then immobilized onto the PVA/PA6–Cu(II) nanofibrous membrane. The amount of immobilized catalase reached a high value of 64 ± 4.6 mg/g, while the kinetic parameters (Vmax and Km) of enzyme were 3774 μmol/mg·min and 41.13 mM, respectively. Furthermore, the thermal stability and storage stability of immobilized catalase were improved significantly. Thereafter, a plug-flow type of immobilized enzyme membrane reactor (IEMR) was assembled from the PVA/PA6–Cu(II)–CAT membrane. With the increase of operational pressure from 0.02 to 0.2 MPa, the flux value of IEMR increased from 0.20 ± 0.02 to 0.76 ± 0.04 L/m2·min, whereas the conversion ratio of H2O2 decreased slightly from 92 ± 2.5% to 87 ± 2.1%. After 5 repeating cycles, the production capacity of IEMR was merely decreased from 0.144 ± 0.006 to 0.102 ± 0.004 mol/m2·min. These results indicated that the assembled IEMR possessed high productivity and excellent reusability, suggesting that the IEMR based on electrospun PVA/PA6–Cu(II) nanofibrous membrane might have great potential for various applications, particularly those related to environmental protection.
Co-reporter:Lei Luo, Rongrong Cui, Hui Qiao, Ke Chen, Yaqian Fei, Dawei Li, Zengyuan Pang, Ke Liu, Qufu Wei
Electrochimica Acta 2014 Volume 144() pp:85-91
Publication Date(Web):20 October 2014
DOI:10.1016/j.electacta.2014.08.048
•We successfully synthesized electrospun CuFe2O4 nanofibers anode material for lithium-ion batteries for the first time.•The as-prepared CuFe2O4 nanofibers calcined at 800 °C exhibited a high initial discharge capacity of 1226.0 mAh g−1, and maintained a stable capacity of 572.4 mAh g−1 after 50 cycles.•The as-prepared CuFe2O4 nanofibers calcined at 800 °C also showed high capacity at higher discharge and charge rate.In this study, copper ferrite (CuFe2O4) nanofibers were successfully fabricated by a combination of electrospinning and calcination process. The crystal structure was investigated by X-ray diffractomentry, and the results show only peaks of CuFe2O4 could be observed from the product obtained at 800 °C, indicating the formation of pure compound. SEM and TEM images showed the as-spun CuFe2O4 nanofibers possessed good continuous fiber morphology with an average diameter of about 66 nm. The electrochemical properties of electrospun CuFe2O4 nanofibers as anode material for lithium-ion batteries were discussed for the first time. The results demonstrated that the electrospun CuFe2O4 nanofibers anode exhibited a high initial discharge capacity of 1226.0 mAh g−1, and maintained a stable capacity of 572.4 mAh g−1 after 50 cycles. Meanwhile, the electrodes showed high capacity at higher discharge and charge rate. The excellent electrochemical properties of electrospun CuFe2O4 nanofibers anode were attributed to the high crystallinity, as well as the unique mesoporous and fibrous structures.Electrospun CuFe2O4 nanofibers were used as anode material for lithium-ion batteries for the first time.
Co-reporter:Xin Xia, Xin Wang, Huiming Zhou, Xiao Niu, Leigang Xue, Xiangwu Zhang, Qufu Wei
Electrochimica Acta 2014 Volume 121() pp:345-351
Publication Date(Web):1 March 2014
DOI:10.1016/j.electacta.2014.01.004
For tin-based anode materials that suffer from poor cycling stability due to severe volume changes upon lithiation/delithiation processes, the morphology control method might provide a solution. Today, coaxial core-shell structure has attracted wide attention due to its ability to accommodate the volume changes of tin (core), which is well encapsulated in the carbon matrix (shell). Coaxial electrospinning is a simple and effective method to prepare this kind of material. In this work, tin was dispersed in the carbon core and then coated a carbon shell to form Sn@C/C nanofibers by coaxial electrospinning. Flow ratio and tin content were investigated as two main critical factors for controlling the core/shell structure, so as to improve the cycling preference of tin anodes. When tested as a lithium-ion battery anode, the material not only showed higher reversible specific capacity (626 mAh g−1) than pure carbon nanofibers, but also exhibited better cycling performance (50 cycles with 73% capacity retention), indicating that the volume change problem of tin anodes has been well resolved by this morphology control.
Co-reporter:Dawei Li, Jie Yang, Jianbo Zhou, Qufu Wei and Fenglin Huang
RSC Advances 2014 vol. 4(Issue 106) pp:61831-61840
Publication Date(Web):07 Nov 2014
DOI:10.1039/C4RA11469H
ZnO loaded carbon nanofibers (ZnO/CNFs) were successfully fabricated by a combination of electrospinning, carbonization and a hydrothermal process. A novel biosensor was fabricated based on a composite of ZnO/CNFs, laccase (Lac), and Nafion. The addition of ZnO/CNFs apparently facilitated the direct electron transfer (DET) between the active center of Lac and the surface of the glassy carbon electrode (GCE). A pair of stable and well-defined redox peaks was observed on the Nafion–Lac–ZnO/CNF modified GCE. Meanwhile, square wave voltammetry (SWV) was employed to investigate the biosensor, and the sensor showed highly efficient electrocatalysis toward hydroquinone with a sensitivity of 28.50 μA μM−1, a detection limit of 9.50 nM (S/N = 3), a linear range from 5.00 × 10−7 to 2.06 × 10−6 M, as well as good selectivity and stability. Furthermore, this novel biosensor was successfully used in detecting hydroquinone in real water samples.
Co-reporter:Qingqing Wang, Avinav G. Nandgaonkar, Jing Cui, Fenglin Huang, Wendy E. Krause, Lucian A. Lucia and Qufu Wei
RSC Advances 2014 vol. 4(Issue 106) pp:61573-61579
Publication Date(Web):03 Nov 2014
DOI:10.1039/C4RA11792A
We report herein for the first time a novel crosslinking approach for the synthesis of grid-like zein nanofibres with SbQ (styrylpyridinequaternary) realized by a simple electrospinning process followed by thermal treatment and/or UV illumination. The properties of the electrospinning solution, such as viscosity, conductivity, and surface tension, were tested to evaluate the effect of SbQ addition (0 wt%, 10 wt%, 20 wt%) on the electrospinnability of glacial acetic acid solution of zein (25 wt%). The incorporation of SbQ resulted in bead-free nanofibre structures with increased diameter compared to pure zein nanofibres. The FT-IR results indicated that the zein-glacial acidic acid protein solution crosslinked, a phenomenon that can be characterized by two discrete, temporally distinct events: inter-molecular solution crosslinking and intra-fiber crosslinking from the SbQ throughout the nanofibrous mat following photocuring. The SbQ can form intra-fiber bridges, as confirmed by the SEM images; on a macroscopic (gross) scale, the crosslinking manifests itself by the formation of grid-like structures. The thermal properties of the zein nanofibres, however, were minimally improved after the incorporation of SbQ, whereas the cured composite nanofibres demonstrated significantly improved tensile and elongation properties.
Co-reporter:Dawei Li, Lei Luo, Zengyuan Pang, Xiaodong Chen, Yibing Cai and Qufu Wei
RSC Advances 2014 vol. 4(Issue 8) pp:3857-3863
Publication Date(Web):01 Nov 2013
DOI:10.1039/C3RA45448G
In this study, a novel hydrogen peroxide (H2O2) electrochemical sensor was fabricated by covering a nanofibrous membrane on a glassy carbon electrode (GCE). Silver (Ag) nanoparticles were deposited on the two surfaces (front and back) of the nanofibrous membrane by a sputtering-deposition process with a high purity silver sputtering target. Cyclic voltammetric measurements revealed that the obtained nanofibrous membrane exhibited a well-defined pair of redox peaks and a prominent electrocatalytic activity toward H2O2. Amperometric measurements indicated that the sensor based on the silver coated nanofibrous membrane showed a linear response to H2O2 concentrations ranging from 10 μM to 16.5 mM with a detection limit of 4 μM and a maximum sensitivity of 157 mA cm−2 M−1. In addition, the sensor also exhibited good selectivity and stability, and can offer a novel method to detect H2O2.
Co-reporter:Huizhen Ke;Zengyuan Pang;Yunfei Xu
Journal of Thermal Analysis and Calorimetry 2014 Volume 117( Issue 1) pp:109-122
Publication Date(Web):2014 July
DOI:10.1007/s10973-014-3669-7
In the present work, a novel PAN-based form-stable composite phase change materials with the methyl stearate (MES) encapsulated in the supporting matrices of polyacrylonitrile (PAN) nanofibers were fabricated through electrospunning for the storage and retrieval of thermal energy. Influences of graphene oxide (GO) addition on the chemical properties, structural morphologies, mechanical properties, thermal energy storage properties, thermal stability, and thermal energy storage/retrieval rates of electrospun MES/PAN/GO phase change composite nanofibers were systematically investigated by FT-IR, FE-SEM, tensile testing, DSC, TG, and measurement of melting/freezing times, respectively. The results revealed that the incorporation of GO effectively enhanced the mechanical properties, thermal stability, as well as heat storage and release rates of the phase change composite nanofibers. The averaged tensile strength of electrospun MES/PAN/GO phase change composite nanofibers increased significantly by 573 % with 10 mass% loading of GO, while elongation at break had a maximum 107 % increment when adding 3 mass% of GO. The DSC results indicated that the electrospun PAN-based phase change composite nanofibers with various GO loadings had suitable phase transition temperatures with the latent heat ranging from about 92 to 109 kJ kg−1 and exhibited good thermal reliability in terms of DSC measurements during 50 melting-freezing cycles. Moreover, the melting and freezing time were significantly decreased about 44 and 43 % for the MES/PAN/GO5, as well as 59 and 64 % for the MES/PAN/GO10 after introducing the GO into the composite nanofibers systems.
Co-reporter:Zengyuan Pang, Jiapeng Fu, Lei Luo, Fenglin Huang, Qufu Wei
Colloids and Surfaces A: Physicochemical and Engineering Aspects 2014 Volume 461() pp:113-118
Publication Date(Web):5 November 2014
DOI:10.1016/j.colsurfa.2014.07.038
•PA6/TiO2/PVP composite nanofibers were prepared by electrospinning–electrospraying.•PA6/TiO2/PANI composite nanofibers show superior ammonia sensing properties.•p–n junction was formed at the interface between PANI and TiO2.•The p–n junction promoted the improvement of ammonia sensing properties.Polyamide 6/titanium dioxide (PA6/TiO2) composite nanofibers were prepared as templates via electrospinning–electrospraying process, in which TiO2 nanoparticles were inserted into PA6 nanofibers mat, and then PA6/TiO2/polyaniline (PANI) composite nanofibers were fabricated by in-situ polymerization of aniline. Structural and morphological of the prepared composite nanofibers were carried out through scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). Their abilities to detect ammonia were evaluated by a home-made test system. It was found that p–n junction was formed at the interface between PANI and TiO2. And due to the p–n junction, the PA6/TiO2/PANI composite nanofibers exhibited good reproducibility, selectivity and apparent improvement in response than that of PA6/PANI composite nanofibers.
Co-reporter:Ping Zhang;Qingqing Wang;Jinning Zhang;Guohui Li
Fibers and Polymers 2014 Volume 15( Issue 1) pp:30-34
Publication Date(Web):2014 January
DOI:10.1007/s12221-014-0030-5
A novel approach to preparing multifunctional composite nanofibrous membrane was developed. Polyacrylonitrile (PAN) nanofibrous membrane was fabricated by electrospinning and then the nitrile groups in PAN copolymer was chemically modified to obtain amidoxime modified PAN (AOPAN) nanofiber membrane which was further used as a functional support for laccase immobilization. During the process of reactive dye degradation catalyzed by the AOPAN nanofiber membrane immobilized with laccase, metal ion adsorption occurred at the same time. The chemical modification was confirmed by Fourier transform spectroscopy (FTIR). Scanning electron microscope (SEM) was employed to investigate the surface morphologies of the electrospun nanofibers before and after laccase immobilization. The effects of environmental factors on laccase activity were studied in detail. It was found that the optimum pH and temperature for the activity of immobilized laccase was 3.5 and 50 °C. The relative activity retention of the immobilized laccase decreased dramatically during the initial four repeated uses. After 20 days’ storage, the activity retention of immobilized laccase was still high above 60 %. It has also proved that laccase immobilized on AOPAN nanofiber membrane performed well in dye degradation and metal ion adsorption.
Co-reporter:Quan Feng;Qingqing Wang;Bin Tang;Anfang Wei;Xueqian Wang;Fenglin Huang;Yibing Cai;Dayin Hou;Songmei Bi
Polymer International 2013 Volume 62( Issue 2) pp:251-256
Publication Date(Web):
DOI:10.1002/pi.4293
Abstract
Amidoxime polyacrylonitrile (AOPAN) nanofibrous membranes were generated by the reaction between electrospun polyacrylonitrile nanofibrous membranes and hydroxylamine hydrochloride. AOPAN nanofibrous membranes were further modified by Fe(III) chelation for immobilizing catalases with coordination bonds. The surface morphologies of the nanofibrous membranes and immobilized catalases were observed by field emission scanning electron microscopy. Chelation of Fe(III) onto AOPAN nanofibrous membranes was studied by the Langmuir isothermal adsorption model. It was found that the maximum amount of coordinated Fe(III) (qm) was 4.5045 mmol g−1 (dry nanofibrous membranes) and the binding constant (Kl) was 0.0698 L mmol−1. The amounts of immobilized enzymes were determined by the method of Bradford. Kinetic parameters were analyzed for both immobilized and free catalases. The value of Vmax (7122.6 µmol mg−1 min−1) for the immobilized catalases was smaller than that for the free catalases (9203.2 µmol mg−1 min−1), and the Km for the immobilized catalases was larger. The immobilized catalases showed better resistance to pH and temperature change than the free catalases, and the storage stability of immobilized catalases was higher than that of free catalases. As for reusability, the immobilized catalases retained 71% of their activity after eight repeated uses. © 2012 Society of Chemical Industry
Co-reporter:Qingqing Wang;Yuanzhi Du;Quan Feng;Fenglin Huang;Keyu Lu;Jingyan Liu
Journal of Applied Polymer Science 2013 Volume 128( Issue 2) pp:1152-1157
Publication Date(Web):
DOI:10.1002/app.38273
Abstract
In this work, polyacrylonitrile (PAN)/graphene oxide (GO) composite nanofibers were prepared by a facile compounding and electrospinning processes. A small amount of GO powders were first dispersed in N,N-dimethylformamide by sonication, and then, PAN powders were added to prepare an electrospinning solution. The surface morphology was analyzed by atomic force microscopy and transmission electron microscopy, whereas the chemical properties of the PAN and PAN/GO composite nanofibers were compared by infrared (IR) spectroscopy. Also, lateral force microscopy and force–distance curves (FDC) were employed to investigate the surface properties, such as friction force and elasticity. The experimental results indicate that with increasing GO concentration, the surface friction force and adhesive force increased, so the nanofibers showed promise for applications as supports for enzyme immobilization. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Co-reporter:Huizhen Ke;Dawei Li;Xiaoling Wang
Journal of Thermal Analysis and Calorimetry 2013 Volume 114( Issue 1) pp:101-111
Publication Date(Web):2013 October
DOI:10.1007/s10973-012-2856-7
An innovative type of nanofibers-based form-stable composite phase change materials for the storage and retrieval of thermal energy was successfully prepared by encapsulating glycerol monostearate (GMS) into the porous structure of polyethylene terephthalate (PET)-supporting matrices on the nanoscale through electrospinning. The field-emission scanning electron microscopy and transmission electron microscopy images revealed that the composite nanofibers possessed desired morphologies with the average fiber diameters ranging from about 290 to 1000 nm which increased with the contents of GMS. The two phase separation (e.g., GMS phase and PET phase) was clearly observed from the images. When GMS content reached 60 %, the amount of the GMS distributing on the surface of the composite nanofibers was significantly increased during the electrospinning. The Fourier transform infrared spectroscopy spectrum proved that the PET supporting matrices were physically combined with GMS molecules. The differential scanning calorimetry analysis indicated that the GMS/PET composite nanofibers had reversible phase change behaviors, and the melting enthalpies increased from 32.63 to 66.99 kJ kg−1 with increasing GMS amount. The TG results showed that both the onset thermal degradation temperature and charred residue of the GMS/PET composite nanofibers at 700 °C were higher than those of pristine GMS powder owing to the better thermal stability of the PET molecules. The tensile testing revealed that the averaged tensile strength and elongation at break of the all GMS/PET composite nanofibers varied from 3.29 to 10.30 MPa and from 2.42 to 42.30 %, respectively.
Co-reporter:Xin Xia;Shuli Li;Xin Wang;Junxiong Liu
Journal of Materials Science 2013 Volume 48( Issue 9) pp:3378-3385
Publication Date(Web):2013 May
DOI:10.1007/s10853-012-7122-7
Two types of SnO2 nanofibers were prepared by electrospinning and calcination of polyvinyl acetate/stannic chloride pentahydrate and polyvinyl pyrrolidone/stannic chloride pentahydrate precursors, respectively. Due to the different properties of polymer solutions and different decomposition mechanisms during calcination, the as-prepared SnO2 nanofibers showed different morphologies and crystal structures. As a result, they exhibited different performance when used as lithium-ion battery anodes and photocatalysts. In the lithium-ion battery test, the SnO2 nanofibers obtained from polyvinyl acetate/stannic chloride pentahydrate precursor showed a higher reversible specific capacity (871 mAh g−1) and better cycling performance (574 mAh g−1 after 20th cycles) because their cobweb-like structure and polycrystalline nature had better ability to accommodate the volume changes of SnO2. On the other hand, SnO2 nanofibers derived from polyvinyl pyrrolidone/stannic chloride pentahydrate precursor exhibited higher photocatalytic degradation of methylene blue (56 %) even at a low concentration of (10−5 M, 50 ml) because they provided higher surface area for absorbing and degrading methylene blue.
Co-reporter:Huizhen Ke;Dawei Li;Huidan Zhang;Xiaoling Wang;Yibing Cai
Fibers and Polymers 2013 Volume 14( Issue 1) pp:89-99
Publication Date(Web):2013 January
DOI:10.1007/s12221-013-0089-4
The four binary fatty acid eutectics of capric-lauric acid (CA-LA), capric-myristic acid (CA-MA), capric-palmitic acid (CA-PA), and capric-stearic acid (CA-SA) were firstly prepared as solid-liquid phase change materials (PCMs); then, the composite phase change nanofibers consisting of CA-based binary fatty acid eutectic and polyethylene terephthalate (PET) were fabricated by electrospinning for thermal energy storage. The maximum mass ratios of fatty acid eutectics versus PET in the nanofibers could reach up to 2/1. The FE-SEM images revealed that the composite nanofibers possessed smooth and cylindrical morphological structure having diameters of about 100–300 nm. The fatty acid eutectic could be uniformly distributed in the three-dimension network structure of the PET nanofibers. The FT-IR results indicated that the fatty acid eutectic and PET had no chemical reaction and exhibited good compatibility with each other. The DSC measurements showed that the prepared composite nanofibers had appropriate phase transition temperatures (about 5–38 °C) based upon climatic requirement, whilst the phase change temperatures and the enthalpy values of the composite nanofibers could be adjusted by changing the contents and the types of binary fatty acid eutectics in the nanofibers. The TGA results suggested that the onset thermal degradation temperatures and charred residues at 700 °C of the composite nanofibers were lower than those of pure PET nanofibers, but higher than those of fatty acid eutectic, which were caused by the fact that the PET had better thermal stability than fatty acid eutectic.
Co-reporter:Qingqing Wang;Lin Peng;Yuanzhi Du;Jing Xu;Yibing Cai
Journal of Porous Materials 2013 Volume 20( Issue 3) pp:457-464
Publication Date(Web):2013 June
DOI:10.1007/s10934-012-9615-9
The electrospun PMMA/O-MMT microfibrous membranes were pretreated by oxygen plasma to create substrates with better adsorption capability. The amount of O-MMT and conditions of plasma treatment were optimized for maximum laccase immobilization on these pretreated surfaces of the microfibrous membranes. The surface morphology and chemistry of the composite microfibrous membranes after plasma treatment and laccase immobilization were investigated by SEM and FTIR. The immobilized laccase showed better resistance to pH and temperature changes than that of the free form laccase, and after 10 successive runs of repeated use, the immobilized laccase still retained 30 % of its initial activity. Reactive X-3B was successfully degraded by both free and immobilized laccase.
Co-reporter:Dawei Li;Zengyuan Pang;Qingqing Wang;Huizhen Ke;Yibing Cai
Fibers and Polymers 2013 Volume 14( Issue 10) pp:1614-1619
Publication Date(Web):2013 October
DOI:10.1007/s12221-013-1614-1
In the present work, polyamide6-room temperature ionic liquid (PA6-RTIL) composite nanofibers and membranes were successfully prepared for the first time by an electrospinning technique. The surface morphology, component analysis, mechanical properties, thermal properties and conductivity of the PA6-RTIL composite membranes were investigated by field-emission scanning electron microscope (FE-SEM), fourier transform infrared spectrometer (FT-IR), tensile testing, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and digit multimeter, respectively. The morphology, fiber diameter, mechanical strength of the obtained fibers can be controlled by changing experimental parameters for electrospinning, especially the content of RTIL in original electrospun mixture solution. The composite fibrous membranes showed ideal mechanical properties and significantly enhanced conductivity, which may be attributed to intrinsic high mechanical strength of PA6 and conductivity of RTIL.
Co-reporter:Yibing Cai, Xiaolin Xu, Chuntao Gao, Tianyu Bian, Hui Qiao, Qufu Wei
Materials Letters 2012 Volume 89() pp:43-46
Publication Date(Web):15 December 2012
DOI:10.1016/j.matlet.2012.08.067
In this study, the capric acid (CA) was chosen and CA series fatty acid eutectics (e.g., capric acid–lauric acid, capric acid–palmitic acid, and capric acid–stearic acid) was prepared; thereafter, the composite phase change materials (PCMs) consisting of CA series fatty acid eutectics and electrospun polyamide 6 (PA6) nanofibers were prepared by physical absorption. The structural morphologies and thermal energy storage properties of the composite PCMs were characterized by SEM and DSC, respectively. The SEM results indicated that the CA series fatty acid eutectics confined into porous PA6 nanofiber membranes. The DSC results indicated that the phase transition temperatures of CA series fatty acid eutectics were lower than those of CA; the enthalpies of melting and crystallization of the composite PCMs were slightly decreased.Graphical abstractHighlights► Composite PCMs consisted of capric acid series fatty acids and polyamide6 nanofibers. ► Phase transition temperatures and heat enthalpies for fatty acids could be adjusted. ► The composite PCMs had high latent heat and suitable phase transition temperatures.
Co-reporter:Hui Qiao, Jing Li, Jiapeng Fu, Dnt Kumar, Qufu Wei, Yibing Cai, and Fenglin Huang
ACS Applied Materials & Interfaces 2011 Volume 3(Issue 9) pp:3704
Publication Date(Web):August 23, 2011
DOI:10.1021/am200884k
In this study, we successfully prepare SnO2 nanoparticles inside the pore channels of CMK-3 ordered mesoporous carbon via sonochemical method. The content of SnO2 is 17 wt % calculated according to the energy-dispersive X-ray spectroscopy (EDS) result. CMK-3 with 17 wt % loading of SnO2 nanoparticles has a large specific surface area and pore volume. Electrochemical performance demonstrates that the ordered SnO2/CMK-3 nanocomposites electrode possesses higher reversible capacity and cycling stability than that of original CMK-3 electrode. Moreover, the ordered SnO2/CMK-3 nanocomposites electrode also exhibits high capacity at higher charge/discharge rate. The improved electrochemical performance is attributed to the nanometer-sized SnO2 formed inside CMK-3 and the large surface area of the mesopores (3.4 nm) in which the SnO2 nanoparticles are formed.Keywords: anode; lithium-ion batteries; nanocomposites; ordered SnO2/CMK-3; sonochemical method;
Co-reporter:Qingqing Wang, Xin Wang, Xuejia Li, Yibing Cai, Qufu Wei
Applied Surface Science 2011 Volume 258(Issue 1) pp:98-102
Publication Date(Web):15 October 2011
DOI:10.1016/j.apsusc.2011.08.013
Abstract
In the present work, poly(methyl methacrylate) (PMMA)/organically modified montmorillonite (O-MMT) composite microfibers were firstly prepared by emulsion polymerization combined with electrospinning, and then coated by nanosize titanium dioxide (TiO2) using RF magnetron sputter technique. The modified surfaces of PMMA/O-MMT composite microfibers were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), UV–vis spectroscopy and drop shape analyzer. Finally, the photocatalytic properties of TiO2 coated PMMA/O-MMT composite microfiber membranes were evaluated by degradation of methylene blue(MB) under UV illumination. The experimental results revealed that anatase-TiO2 and rutile-TiO2 nanoparticles were well spread and physically deposited on the surface of PMMA/O-MMT microfibers, and the wettability of the PMMA/O-MMT composite microfibers was improved after surface modification by sputter coating. Furthermore, the PMMA/O-MMT microfibers membrane coated with TiO2 performed well in photocatalytic degradation of MB.
Co-reporter:Quan Feng;Xin Xia;Anfang Wei;Xueqian Wang;Dayin Huo;Anjing Wei
Journal of Applied Polymer Science 2011 Volume 120( Issue 6) pp:3291-3296
Publication Date(Web):
DOI:10.1002/app.33493
Abstract
Poly(vinyl alcohol) (PVA) nanofibers were formed by electrospinning. Metal chelated nanofibrous membranes were prepared by reaction between Cu(II) solution and nanofibers, and which were used as the matrix for catalases immobilization. The constants of Cu(II) adsorption and properties of immobilized catalases were studied in this work. The Cu(II) concentration was determined by atomic absorption spectrophotometer (AAS), the immobilized enzymes were confirmed by the Fourier transform infrared spectroscopy (FTIR), and the amounts of immobilized enzymes were determined by the method of Bradford on an ultraviolet spectrophotometer (UV). Adsorption of Cu(II) onto PVA nanofibers was studied by the Langmuir isothermal adsorption model. The maximum amount of coordinated Cu(II) (qm) was 2.1 mmol g−1 (dry fiber), and the binding constant (Kl) was 0.1166 L mmol−1. The immobilized catalases showed better resistance to pH and temperature inactivation than that of free form, and the thermal and storage stabilities of immobilized catalases were higher than that of free catalases. Kinetic parameters were analyzed for both immobilized and free catalases. The value of Vmax (8425.8 μmol mg−1) for the immobilized catalases was smaller than that of the free catalases (10153.6 μmol mg−1), while the Km for the immobilized catalases were larger. It was also found that the immobilized catalases had a high affinity with substrate, which demonstrated that the potential of PVA-Cu(II) chelated nanofibrous membranes applied to enzyme immobilization and biosensors. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Co-reporter:Quan Feng;Xueqian Wang;Anfang Wei;Dayin Hou;Wei Luo
Fibers and Polymers 2011 Volume 12( Issue 8) pp:1025-1029
Publication Date(Web):2011 December
DOI:10.1007/s12221-011-1025-0
Ployacrylonitrile (PAN) nanofibers were formed by electrospinning. Amidoxime ployacrylonitrile (AOPAN) nanofibers were prepared by reaction with hydroxylamine hydrochloride, which were used as the matrix for metal ions chelation. FTIR spectra of the PAN nanofibers and AOPAN nanofibers were recorded for analysis of the surface chemical structures. The AOPAN conventional fibers were also prepared for comparison, and surface morphologies of the modified PAN conventional fibers and PAN nanofibers were observed by FESEM. Metal ions concentrations were calculated by AAS. The chelated isothermal process and kinetics parameters of the modified PAN nanofibers and PAN conventional fibers were studied in this work. Results indicated that the saturated coordinate capacity of AOPAN nanofibers to Cu2+, Cd2+ was 3.4482 and 4.5408 mmol/g (dry fiber) respectively, nearly two times higher than that of AOPAN conventional fibers. Besides, the desorption rate of Cu2+ and Cd2+ from metal chelated AOPAN nanofibers was 87 and 92 % respectively in 1 mol/l nitric acid solution for 60 min. The isothermal processes were found to be in conformity with Langmuir model.
Co-reporter:Dongfeng Shao;Dawei Gao;Lizhen Tao;Hong Zhu
Fibers and Polymers 2011 Volume 12( Issue 2) pp:214-219
Publication Date(Web):2011 April
DOI:10.1007/s12221-011-0214-1
In this study, the surface functionalization of polyacrylonitrile (PAN) fibers was achieved by depositing ZnO nanoparticles using thermal solvent coating. surface morphology, crystalline structure, surface chemistry, thermal stability and washing stability of the ZnO coated PAN fibers were investigated by scanning electron microscope (SEM), X-ray diffractometer (XRD), Fourier transform Infra red spectroscopy (FT-IR), Thermo-gravimetric analyses (TGA) and washing stability test, respectively. In addition, the weight changes after coating and washing were studied at different coating and washing conditions. The SEM images revealed that the ZnO was well coated on the surface of the PAN fibers and the coating was obviously affected by the experimental temperature. The FT-IR spectra indicated the chemical features of the deposited ZnO nanostructures. The XRD patterns showed that there was a typical crystalline structure of ZnO nanogains formed on the PAN fibers after coating. The TGA results revealed that the thermal stability of the PAN fibers was improved by the ZnO coating. The experimental results of washing stability revealed the effect of temperature on the washing stability. Weight measurements indicated that the amount of ZnO deposited on PAN fibers increased with the increasing of coating temperature from 60 to 70 °C. Weight measurements also revealed that the weight of the ZnO coating on fibers decreased with the increase in washing temperature and washing time.
Co-reporter:Dongfeng Shao, Dawei Gao, Qufu Wei, Hong Zhu, Lizhen Tao, Mingqiao Ge
Applied Surface Science 2010 Volume 257(Issue 4) pp:1306-1309
Publication Date(Web):1 December 2010
DOI:10.1016/j.apsusc.2010.08.056
Abstract
The polyacrylonitrile (PAN) fabric coated with ZnO–Ag composite was achieved by hydrothermal synthesis techniques and photochemical method. The PAN fabrics coated with ZnO–Ag composite were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR), UV–vis spectrophotometer and fabric induced static tester, respectively. The SEM images revealed the formation of the coating aggregates on the fiber surface. The FT-IR spectra and XRD patterns revealed the chemical structures of the coatings on the PAN fabrics. The results of UV–vis test showed that there was an obvious increase in ultraviolet resistant properties after coating. The antistatic properties results revealed the improvement in the antistatic performance of coated fabrics, attributed to the superior electrical and optical properties of ZnO and Ag.
Co-reporter:Dan Tao;Quan Feng;Dawei Gao;Liang Pan;Dejuan Wang
Journal of Applied Polymer Science 2010 Volume 117( Issue 3) pp:1624-1630
Publication Date(Web):
DOI:10.1002/app.32067
Abstract
In this study, melt-blown polypropylene (PP) nonwovens were used as substrates for the metallic deposition of copper. The substrates were pretreated by O2 plasma, followed by treatments such as sensitization, activation, and reduction. The effects of the copper sulfate concentration, reaction temperature, and plasma power on the conductivity and adhesion strength of the PP nonwovens were investigated after copper deposition. The morphology of the PP nonwovens after copper deposition, analyzed by scanning electron microscopy and atomic force microscopy, revealed that copper nanoclusters were deposited on the fiber surface with a smooth surface morphology and dense structure. X-ray photoelectron spectroscopy indicated that the copper was present mainly in the form of the elementary substance, which coexisted with a little Cu2+. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Co-reporter:Qi Li;Dawei Gao;Mingqiao Ge;Weimin Liu;Lejiang Wang;Keqin Hu
Journal of Applied Polymer Science 2010 Volume 117( Issue 3) pp:1572-1577
Publication Date(Web):
DOI:10.1002/app.32017
Abstract
This research is mainly to investigate the thermal and crystalline differences between polyamide 6/montmorillonite (PA6/MMT) and polyamide 6/organo-montmorillonite (PA6/O-MMT) nanofibers, which were both prepared by electrospinning under the same process conditions. The structures of PA6/MMT and PA6/O-MMT nanofibers were observed by scanning electrical microscope. It was identified that the interval between O-MMT clays was increased in the PA6 matrix compared to that of MMT, which was detected by X-ray diffraction (XRD). The thermal properties of PA6 nanofibers contained O-MMT particles were more efficient than PA6/MMT nanofibers, that was verified using thermal gravimetric analysis. The crystalline properties of the electrospun nanofibers was investigated using differential scanning calorimeter and it was found that the degree of crystallinity in the PA6 nanofibers loaded with O-MMT was much higher than PA6/MMT and PA6 nanofibers. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Co-reporter:Anfang Wei;Juan Wang;Xueqian Wang;Mingqiao Ge;Dayin Hou
Journal of Applied Polymer Science 2010 Volume 118( Issue 1) pp:346-352
Publication Date(Web):
DOI:10.1002/app.32363
Abstract
Electrospinning was applied to prepare the drug-loaded nanofibers for potential use in drug delivery and wound healing. Clarithromycin (CLM) was selected as the model drug, whereas poly(l-lactic acid) (PLLA) was used as the biodegradable and biocompatible polymer carrier. The low toxicity solvents were tested, and the morphology and structures of the nanofibers were investigated by scanning electron microscopy (SEM), Fourier transform infrared spectrometer (FTIR), and X-ray diffraction (XRD). PLLA and its composite of CLM were electrospun using the solvents of dichloromethane and acetone. SEM images showed that the diameters of the electrospun PLLA fibers were about 1000 nm, decreased to about 400 nm when 5 wt % CLM was loaded. With the increase of the amount the drug loaded, the diameters of the fibers gradually decreased and their distributions varied. The drug aggregates of any kind were not observed on the surfaces of the fibers. FTIR spectra revealed that CLM was incorporated into the macromolecular carrier of PLLA by formation of the hydrogen bonds but no new functional groups in the structure of the composite nanofibers were formed. XRD patterns indicated that the drug distributed in the composite nanofibers existed in the noncrystalline form. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Co-reporter:Hui Qiao, Ning Wu, Fenglin Huang, Yibing Cai, Qufu Wei
Materials Letters 2010 Volume 64(Issue 9) pp:1022-1024
Publication Date(Web):15 May 2010
DOI:10.1016/j.matlet.2010.01.037
NiO/C hybrid microspheres were prepared via a one-pot solvothermal approach for the first time. The carbon in the composite was amorphous by the X-ray diffraction (XRD) analysis, and its content was 20.1 wt.% calculated according to the energy dispersive X-ray spectroscopy (EDS) result. Field-emission scanning electron microscope (SEM) and transmission electron microscopy (TEM) images revealed that the diameter of these as-prepared spheres varied from 1.0 to 2.0 μm. Electrochemical performance demonstrated that the reversible capacity of the annealed NiO/C hybrid microspheres after 20 cycles was 387 mAh g−1, which was much higher than that of NiO nanoparticles. These improvements can be ascribed to the carbon, which can enhance the conductivity of NiO, suppress the aggregation of active particles, and increase their structural stability during cycling.
Co-reporter:Xin Xia;Huifeng Wang;Fenglin Huang;Yibing Cai
Fibers and Polymers 2010 Volume 11( Issue 6) pp:813-818
Publication Date(Web):2010 September
DOI:10.1007/s12221-010-0813-2
Nanostructured silver thin films were sputtered onto the aromatic thermotropic liquid crystalline fibers of Vectran by magnetron sputtering technology. Plasma treatment was used as pre-treatment in order to improve the deposition of the coating layer. Surface morphology of the coated fibers was examined by scanning electron microscopy (SEM) and atomic force microscopy (AFM). A full energy dispersive X-ray analysis (EDX) was used to detect the elemental composition of the material. Its conductivity and mechanical properties were measured and analyzed as well. The study revealed that a very thin conductive silver deposition exhibited high electrical conductivity as well as less influence on the mechanical properties of the pre-treated Vectran fiber. The plasma treatment could improved the deposition of the coating layer, but the surface roughness caused by plasma treatment also affected the surface conductivity. It was found that the surface resistivity could reach very low value of 1.66×10−3 Ω·cm after sputtering deposition for 30 min.
Co-reporter:Yang Xu;Huifeng Wang;Huishan Liu
Journal of Coatings Technology and Research 2010 Volume 7( Issue 5) pp:637-642
Publication Date(Web):2010 September
DOI:10.1007/s11998-010-9243-8
Nanoscale titanium dioxide (TiO2) films were deposited on the surface of polyester nonwovens by using direct current (DC) reactive magnetron sputtering. The effect of coating thickness on the surface structures and properties of TiO2 coated fabrics was investigated by atomic force microscope (AFM), X-ray diffraction (XRD), energy dispersive X-ray analysis system (EDX), scanning electron microscope (SEM), and antistatic test in this article. The results indicated that the grain sizes of the sputtered clusters increased and the coating layer became more compact as film thickness was increased, but the crystal structure did not have any significant change. At the same time, the film mechanical properties and antistatic performance in general depended strongly on the film thickness which could lead to the optimum thickness for a particular application.
Co-reporter:Qufu Wei;Dongfeng Shao;Bingyao Deng
Journal of Coatings Technology and Research 2010 Volume 7( Issue 1) pp:
Publication Date(Web):2010 January
DOI:10.1007/s11998-009-9164-6
Ceramic fibers were functionalized by the sputter coating of copper in this study. The surface and interface structures of the functionalized ceramic fibers were investigated by atomic force microscopy (AFM) and environmental scanning electron microscopy (ESEM). The observations by AFM revealed the formation of nanoclusters on the fiber surface. The coated layer of the sputtered copper was also confirmed by the ESEM examination, equipped with an energy-dispersive X-ray analysis. It was also found that the electrical resistance of the ceramic fibers decreased with increased coating thickness. The interfacial bonding between fibrous substrate and sputter-coated copper was investigated and discussed by peel-off tests in this study. The mechanism of the interfacial adhesion between copper and fiber substrate was also discussed.
Co-reporter:Qufu Wei;Huifeng Wang;Yang Xu
Journal of Coatings Technology and Research 2010 Volume 7( Issue 4) pp:511-514
Publication Date(Web):2010 July
DOI:10.1007/s11998-009-9207-z
In this study, transparent conductive films of tin-doped indium oxide (ITO) were deposited onto the polyamide 6 (PA6) nanofiber substrates at room temperature. Atomic force microscopy (AFM) was employed to study the morphology of the nanofibers, respectively. The AFM results indicated a significant change in the morphology of the nanofibers before and after the ITO sputter coatings. The light transmittance and surface conductivity of the ITO-deposited nanofibers were also investigated. It was found that the surface resistivity of the PA6 nanofiber with the ITO deposition had a significant drop and the ITO deposition obviously affected the light transmittance of the PA6 nanofibers.
Co-reporter:Hui Qiao, Dan Tao, Yawen Wang, Yibing Cai, Fenglin Huang, Xiao Yang, Jinzhu Wei, Qufu Wei
Chemical Physics Letters 2010 490(4–6) pp: 180-183
Publication Date(Web):
DOI:10.1016/j.cplett.2010.03.037
Co-reporter:Ning Wu;Dongfeng Shao;Yibing Cai ;Weidong Gao
Journal of Applied Polymer Science 2009 Volume 112( Issue 3) pp:1481-1485
Publication Date(Web):
DOI:10.1002/app.29535
Abstract
Polyvinyl acetate (PVAc)/titanium dioxide (TiO2) hybrid nanofibers were fabricated by combining sol–gel process with electrospinning technology, which consisted of PVAc as organic segment and TiO2 as inorganic part. The surface structures of the PVAc/TiO2 hybrid nanofibrous mats were examined using scanning electron microscopy (SEM). The surface morphology and bulk structures of single nanofiber were investigated by atomic force microscopy (AFM) and transmission electron microscopy (TEM). Fourier transform infrared spectroscopy (FTIR) was employed to analyze the chemical structures of the PVAc/TiO2 hybrid nanofibers. SEM scanning revealed that the fibrous structure was formed. AFM observations presented a significant difference in the morphology of the nanofibers before and after hybridization. It was observed from TEM images that some black streaks with various lengths distributed in a nanofiber. The FTIR analysis indicated the newly formed associated hydrogen bond because of the hybrid effect between PVAc and TiO2 sol. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Co-reporter:Qufu Wei;Dongfeng Shao;Bingyao Deng;Yang Xu
Journal of Applied Polymer Science 2009 Volume 114( Issue 3) pp:1813-1819
Publication Date(Web):
DOI:10.1002/app.30672
Abstract
In this study, the polypropylene (PP) spunbonded nonwoven materials were used as substrates for depositing transparent nanostructures on the fiber surfaces. Magnetron sputter coating technique was used to deposit tin-doped indium oxide (ITO) and aluminum-doped zinc oxide (AZO) films onto the nonwoven substrates. The structures and properties of the deposited ITO and AZO films were investigated and compared using atomic force microscopy, energy-dispersive X-ray (EDX), and electrical and optical tests. The observations by atomic force microscopy revealed the formation of functional nanostructures on the fiber surfaces. EDX analyses confirmed the deposition of ITO and AZO functional films on the PP fibers. It was found that ITO had more compact structures on the fiber surface than AZO under the same sputtering conditions. The transmittance analysis revealed that the nonwoven substrates deposited with nanostructural AZO showed better ultraviolet shielding effect than those coated with ITO in the same thickness. The nonwoven materials coated with ITO had lower electrical resistance than those coated with AZO in the same thickness. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Co-reporter:Yang Xu;Ning Wu;Xiubiao Pi
Journal of Coatings Technology and Research 2009 Volume 6( Issue 4) pp:
Publication Date(Web):2009 December
DOI:10.1007/s11998-008-9149-x
Nanoscale titanium dioxide (TiO2) films were deposited on the surface of polyester nonwovens by using direct current reactive magnetron sputtering. The effect of oxygen flow on the surface structures and properties of the fabrics was investigated in this article. The surface morphology, microstructure, and the chemical composition of TiO2-coated fibers were characterized by atomic force microscope, X-ray diffraction, and X-ray photoelectron spectroscopy. The effect of oxygen flow on deposition rate, white degree, and light transmission properties of the fabrics with nanoscale TiO2 films were examined. The test results proved that the oxygen flow was a key factor in sputter processing. The deposition speed decreased and the white degree of the fabric increased with increasing oxygen flow. The ultra-violet absorption by the polyester nonwoven fabric with TiO2 coatings was also enhanced as the oxygen flow increased in a proper range.
Co-reporter:Yibing Cai, Fenglin Huang, Qufu Wei, Lei Song, Yuan Hu, Yun Ye, Yang Xu, Weidong Gao
Polymer Degradation and Stability 2008 Volume 93(Issue 12) pp:2180-2185
Publication Date(Web):December 2008
DOI:10.1016/j.polymdegradstab.2008.08.003
In the present work, Fe-montmorillonite (Fe-MMT) was synthesized by hydrothermal method, and then was modified by cetyltrimethyl ammonium bromide (CTAB). The polyamide 6 (PA6)/organic-modified Fe-montmorillonite (Fe-OMT) nanocomposite fibers were prepared by a facile compounding and electrospinning. The catalyzing carbonization studies of the Fe-OMT based on PA6 nanocomposite fibers were performed. It was found from High-resolution electron microscopic (HREM) observations that the silicate clay layers were well dispersed within the nanocomposite fibers and was oriented along the fiber axis. The Scanning electron microscopic (SEM) images indicated that the nanofibers were randomly distributed to form the fibrous web and the Fe-OMT additives decreased the diameters of nanocomposite fibers. The Thermogravimetric analyses (TGA) revealed that the loading of the Fe-OMT led to the crosslinking of the PA6, promoted the charred residue yield and catalytic graphitization effect. The structure and morphology of the purified charred residue, characterized by XRD, HREM, Selected area electron diffraction (SAED) and Laser Raman spectroscopic (LR), approved further the presence of graphite sheets. The possible catalyzing carbonization mechanisms included: (1) catalyzing effect of the Fe3+, which promoted the crosslinking of polymer, (2) Hofmann degradation of the Fe-OMT, whose degraded products had also positive role in promoting crosslinking reactions, (3) gas barrier properties of the nano-dispersed silicate clay layers stopped or reduced the releases of the pyrolytic products, which was dehydrogenated and aromatized to form graphite.
Co-reporter:Dongfeng Shao, Qufu Wei, Liwei Zhang, Yibing Cai, Shudong Jiang
Applied Surface Science 2008 Volume 254(Issue 20) pp:6543-6546
Publication Date(Web):15 August 2008
DOI:10.1016/j.apsusc.2008.04.055
Abstract
In this paper the functional carbon nanofibers were prepared by the carbonization of ZnO coated PAN nanofibers to expand the potential applications of carbon nanofibers. Polyacrylonitrile (PAN) nanofibers were obtained by electrospinning. The electrospun PAN nanofibers were then used as substrates for depositing the functional layer of zinc oxide (ZnO) on the PAN nanofiber surfaces by sol–gel technique. The effects of coating, pre-oxidation and carbonization on the surface morphology and structures of the nanofibers were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) and Scanning electron microscopy (SEM), respectively. The results of SEM showed a significant increase of the size of ZnO nanograins on the surface of nanofibers after the treatments of coating, pre-oxidation and carbonization. The observations by SEM also revealed that ZnO nanoclusters were firmly and clearly distributed on the surface of the carbon nanofibers. FTIR examination also confirmed the deposition of ZnO on the surface of carbon nanofibers. The XRD analysis indicated that the crystal structure of ZnO nanograins on the surface of carbon nanofibers.
Co-reporter:Qufu Wei;Liangyan Yu;Dayin Hou;Fenglin Huang
Journal of Applied Polymer Science 2008 Volume 107( Issue 1) pp:132-137
Publication Date(Web):
DOI:10.1002/app.26940
Abstract
Nonwoven materials have been increasingly used in many industries. The surface properties of nonwoven materials are of importance in these applications. In this study, functional nonwoven materials were prepared by sputtering deposition of copper (Cu), zinc oxide (ZnO), and polytetrafluoroethylene (PTFE) on the surface of polypropylene (PP) fibers. Atomic Force Microscopy (AFM) and Environmental Scanning Electron Microscopy (ESEM) were employed to study the surface morphology and chemical compositions. The observations by AFM revealed the formation of functional nanostructures on the fibre surfaces and the ESEM examination confirmed the formation of functional compositions on the fiber surface. The metallic coating of Cu significantly improved the surface conductivity of the material. The transmittance analysis indicated that the ZnO coating obviously increased the ultra-violet absorption of the material. The surface hydrophobicity of the nonwoven material was enhanced by the sputter coating of PTFE. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Co-reporter:Qi Li;Ning Wu;Yibing Cai ;Weidong Gao
Journal of Applied Polymer Science 2008 Volume 107( Issue 6) pp:3535-3540
Publication Date(Web):
DOI:10.1002/app.27529
Abstract
A facile compounding process, which combined nanocomposite process with electrospinning for preparing novel polyamide6/organic modified montmorillonite (PA6/O-MMT) composite nanofibers, is reported. In this compounding process, the O-MMT slurry was blended into the formic acid solution of PA6 at moderate temperatures, where the nanosized O-MMT particles were first dispersed in N,N-dimethyl formamide solvent homogeneously via ultrasonic mixing. Subsequently the solution via electrospinning formed nanofibers, which were collected onto aluminum foil. The O-MMT platelets were detected to be exfoliated at nanosize level and dispersed homogeneously along the axis of the nanofibers using an electron transmission microscope. Scanning electron microscope and atomic force microscope were used to analysis the size and surface morphology of polyamide6/O-MMT composite nanofibers. The addition of O-MMT reduced the surface tension and viscosity of the solution, leading to the decrease in the diameter of nanofiber and the formation of rough and ridge-shape trails on the nanofiber surface. The behavior of the dynamic water adsorption of composite nanofibers was also investigated and discussed in this article. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Co-reporter:Ya Liu;Ning Wu;Yibing Cai ;Anfang Wei
Journal of Applied Polymer Science 2008 Volume 110( Issue 5) pp:
Publication Date(Web):
DOI:10.1002/app.28904
Abstract
Poly(L-lactic acid) (PLLA) fibers have been extensively studied for various applications. In this work, PLLA and poly(vinyl alcohol) (PVA) were prepared by coelectrospinning to form composite nonwoven materials. The structures and diameter distribution of the electrospun PLLA/PVA composite nonwovens were examined by atomic force microscopy (AFM) and scanning electronic microscope (SEM). The wetting behavior of the electrospun PLLA/PVA composite nonwovens was also investigated using static contact angles and dynamic water adsorption measurements. It was observed that the addition of PVA in the electrospun PLLA/PVA composite nonwovens significantly alerted the contact angles and water adsorption of the composite materials. It was also found that the increase in the content of PLLA led to the increase in the surface contact angle and decrease in water adsorption of the electrospun PLLA/PVA nonwoven materials. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Co-reporter:Bingyao Deng;Weidong Gao
Journal of Coatings Technology and Research 2008 Volume 5( Issue 3) pp:393-397
Publication Date(Web):2008 September
DOI:10.1007/s11998-008-9087-7
In this study, the polyethylene terephthalate (PET) spunbonded nonwoven materials were used as substrates for creating electro-optical functional nanostructures on the fiber surfaces. A magnetron sputter coating was used to deposit Al-doped ZnO (AZO) films onto the nonwovens. The influences of the deposition time on the structural, optical, and electrical properties of AZO films were investigated. Atomic force microscopy (AFM) was employed to examine the topography of the fibers. The AFM observation revealed a significant difference in the morphology of the fibers before and after the AZO sputter coating. The examination by UV–visible spectrophotometer analysis showed that the nonwovens deposited with transparent nanostructure AZO films had better UV absorption, and an average transmittance was approximately 50% in the visible light wavelength region. The surface conductivity of the materials was analyzed using a four-probe meter, and it was found that electrical resistance was significantly decreased as the sputtering time increased.
Co-reporter:Dan Tao;Yibing Cai;Qiuxiang Xu
Journal of Coatings Technology and Research 2008 Volume 5( Issue 3) pp:399-403
Publication Date(Web):2008 September
DOI:10.1007/s11998-008-9118-4
Polyamide 6 (PA6) nanofibers were prepared via electrospinning. The electrospun PA6 nanofibers were functionalized using electroless deposition technique. Oxygen low temperature plasma treatment was applied to substitute the conventional roughening process using concentrated sulfuric acid-potassium dichromate. The deposition of copper (Cu) on the PA6 nanofibers was characterized using scanning electron microscopy (SEM), atomic force microscopy (AFM), and energy dispersive X-ray spectroscopy (EDX). The observations revealed the uniform coating of the PA6 nanofibers with thin films of Cu. It was also found that the surface conductivity of the PA6 nanofibers was significantly improved by the Cu deposition. The combination of electrospinning and electroless deposition will provide a new approach to producing the functional nanofibers for various applications.
Co-reporter:Huizhen Ke, Mohy uddin Hafiz Ghulam, Yonggui Li, Jing Wang, Bin Peng, Yibing Cai, Qufu Wei
Renewable Energy (December 2016) Volume 99() pp:1-9
Publication Date(Web):1 December 2016
DOI:10.1016/j.renene.2016.06.033
•The magnetron sputtering was used to improve the heat transfer rates of PCMs.•The quinary fatty acid eutectics were prepared as solid-liquid PCMs.•The Ag-coated PU nanofibers were selected as supporting materials.•The prepared composites PCMs possessed melting enthalpies about 110 kJ/kg.•The melting time declined by 21%–65% due to the coating of Ag nanoparticles.The novel quinary fatty acid eutectic (CA-LA-MA-PA-SA) of capric acid, lauric acid, myristic acid, palmitic acid and stearic acid was successfully prepared with the mass ratio of 61.09/24.61/8.13/4.01/2.16. Thereafter, the innovative Ag-coated polyurethane (PU) fibers membranes with different concentrations of Ag, which were selected as a supporting material to adsorb the CA-LA-MA-PA-SA eutectics, were successfully fabricated through electrospinning followed by magnetron sputter. The energy dispersive X-ray confirmed that Ag nanoclusters were successfully deposited on the surface of PU fibers as a result of sputter coating. The observations of atomic force microscope indicated that the surface roughness of the PU fibers significantly increased with increase in coating time. The scanning electron microscope images demonstrated that the CA-LA-MA-PA-SA eutectics were uniformly distributed into the three-dimensional porous structures of uncoated and Ag-coated PU fibers membranes. Furthermore, the differential scanning calorimeter curves suggested that the CA-LA-MA-PA-SA/PU/Ag composites phase change materials (PCMs) possessed melting enthalpies about 110 kJ/kg and melting temperature around 17 °C. The absorption ratios of the CA-LA-MA-PA-SA eutectic in composite PCMs was approximately at 73.74%–83.18%. The investigation on thermal performance indicated that we achieved higher melting and freezing rates of the CA-LA-MA-PA-SA/PU/Ag composites PCMs by increasing coating time. In addition to this, after depositing Ag nanoparticles the melting and freezing times of composites PCMs were shortened to about 21%–65%.
Co-reporter:Hangyi Lu, Qingqing Wang, Guohui Li, Yuyu Qiu, Qufu Wei
Materials Science and Engineering: C (1 May 2017) Volume 74() pp:
Publication Date(Web):1 May 2017
DOI:10.1016/j.msec.2017.02.004
•A simple, non-toxic and cost-effective way to improve water stability of zein nanofibers was proposed.•Electrospun zein/ethyl cellulose nanofibers with improved water stability and mechanical strength were prepared.•Indomethacin was homogeneously distributed in the zein/ethyl cellulose nanofibers with no aggregation or cluster.•The zein/ethyl cellulose nanofibers presented a sustained drug release profile, following Fickican diffusion mechanism.A simple and cost-effective way to prepare water-stable zein-based nanofibers for potential drug delivery was presented in this article. Corn protein zein was co-electrospun with hydrophobic ethyl cellulose. Indomethacin, as a model drug, was incorporated in situ into the composite nanofibers. Scanning electron microscopy and element mapping revealed the morphologies of drug-loaded nanofibers and drug distribution, respectively. Fourier transform infrared spectra confirmed the physical blending among the components. Differential scanning calorimetry and X-ray diffraction demonstrated the physical state of drug and polymers in the nanofiber matrix. The composite nanofibers showed a sustained diffusion-controlled release according to the results of in vitro dissolution tests.
![Poly[(5,7-dihydro-1,3,5,7-tetraoxobenzo[1,2-c:4,5-c']dipyrrole-2,6(1H,3H)-diyl)-1,4-phenyleneoxy-1,4-phenylene]](http://img.cochemist.com/ccimg/25100/25036-53-7.png)
![Poly[(5,7-dihydro-1,3,5,7-tetraoxobenzo[1,2-c:4,5-c']dipyrrole-2,6(1H,3H)-diyl)-1,4-phenyleneoxy-1,4-phenylene]](http://img.cochemist.com/ccimg/25100/25036-53-7_b.png)
![POLY[OXY-1,4-PHENYLENEIMINOCARBONYL(DICARBOXYPHENYLENE)CARBONYLIMINO-1,4-PHENYLENE]](http://img.cochemist.com/ccimg/9100/9043-05-4.png)
![POLY[OXY-1,4-PHENYLENEIMINOCARBONYL(DICARBOXYPHENYLENE)CARBONYLIMINO-1,4-PHENYLENE]](http://img.cochemist.com/ccimg/9100/9043-05-4_b.png)
