Co-reporter:Conghui Yuan, Bihong Hong, Ying Chang, Jie Mao, Yang Li, Yiting Xu, Birong Zeng, Weiang Luo, Jean-François Gérard, and Lizong Dai
ACS Applied Materials & Interfaces May 3, 2017 Volume 9(Issue 17) pp:14700-14700
Publication Date(Web):April 7, 2017
DOI:10.1021/acsami.7b02252
Covalently stabilized polymer assemblies are normally fabricated from the self-assembly of polymer chains followed by a cross-linking reaction. In this report, we show that a cross-linking-induced self-assembly approach, in which boronate cross-linking sites are formed by the condensation reaction between boronic and catechol groups, can organize polymer networks into uniform assemblies. Self-assembly of these boronate cross-linked polymer networks adopts two different driving forces in water and methanol solutions. Hydrophobic aggregation of polymer networks in water solution affords spherical assemblies, while B–N dative bond formed between boronate and imine functionalities in methanol solution organizes the polymer networks into bundle-like assemblies. We not only demonstrate the intrinsic stimuli-responsive degradability of these cross-linked assemblies but also show that their degradation can cause a controllable release of guest molecules. Moreover, bundle-like assemblies with rough surface and exposed boronate functionalities exhibit dramatically higher cell penetration capability than the spherical assemblies with smooth surface and embedded boronate functionalities.Keywords: cell uptake; cross-linking polymers; degradation; self-assembly; stimuli-response;
Co-reporter:Ying Chang;Conghui Yuan;Yuntong Li;Cheng Liu;Tong Wu;Birong Zeng;Yiting Xu
Journal of Materials Chemistry A 2017 vol. 5(Issue 4) pp:1672-1678
Publication Date(Web):2017/01/24
DOI:10.1039/C6TA09239J
A valid pathway has been exploited to create a B,N co-doped carbon shell on the surface of TiO2 nanoparticles (TiO2@CNB) as a support of Pt nanoparticles. The shell thickness of TiO2@CNB can be easily controlled by pyrolysis of TiO2@polymer networks. The as-prepared Pt/TiO2@CNB catalyst with a thicker CNB layer of 5.0 ± 0.5 nm shows improved performance for the oxygen reduction reaction (ORR) with high onset (0.65 V) and half-wave potentials (0.56 V), which are significantly higher than those of commercial Pt/C (20 wt%) catalysts. For the methanol oxidation reaction (MOR), the Pt/TiO2@CNB catalyst with a moderate CNB layer of 3.3 ± 0.3 nm thickness demonstrates the highest activity and stability compared with that with a CNB thickness of 2.1 ± 0.3, or 5.0 ± 0.5 nm, even Pt/C. Our findings indicate that the synergy between Pt nanoparticles and the B,N co-doped carbon shell, as well as the shell thickness plays a key role in improving the electrochemical performances of the Pt/TiO2@CNB composite materials.
Co-reporter:Cunfeng Song, Meijie Wang, Xin Liu, He Wang, Xiaoling Chen, Lizong Dai
Materials Science and Engineering: C 2017 Volume 78(Volume 78) pp:
Publication Date(Web):1 September 2017
DOI:10.1016/j.msec.2017.03.042
•RAFT polymerization has been introduced to fabricate ion-exchange membrane.•QPMAMP brushes formed 3-dimensional nanolayer on the surface of composite membrane.•Their straight pore structure is favorable to the convective transport of solutes.•The strong anion-exchange membrane exhibits high adsorption capacity.•The strong anion-exchange membrane exhibits easy elution and high selectivity.Surface-initiated reversible addition-fragmentation chain transfer (RAFT) polymerization has been utilized to fabricate high-capacity strong anion-exchange (AEX) membrane for the separation of protein. By means of RAFT polymerization, quaternized poly(3-(methacrylamidomethyl)-pyridine) brushes formed 3-dimensional nanolayers on the surface of porous anodic aluminum oxide (AAO)-silica composite membrane. The surface properties of the membranes were analyzed by SEM, water contact angle, ATR-FTIR, XPS and TGA. To investigate the adsorption performance, the new AEX membranes were applied to recover a model protein, ovalbumin (OVA). High adsorption capacities of 95.8 mg/g membranes (static) and 65.3 mg/g membranes (dynamic) were obtained at ambient temperature. In the further studies, up to 90% of the adsorbed OVA was efficiently eluted by using phosphate buffer-1 M NaCl as elution medium. The successful separation of OVA with high purity from a mixture protein solution was also achieved by using the AEX membranes. The present study demonstrated that under mild reaction condition, RAFT polymerization can be used to fabricate ion-exchange membrane which has many remarkable features, such as high capacity and selectivity, easy elution and so on.
Co-reporter:Cheng Liu;Ting Chen;Conghui Yuan;Ying Chang;Guorong Chen;Birong Zeng;Yiting Xu;Weiang Luo
RSC Advances (2011-Present) 2017 vol. 7(Issue 73) pp:46139-46147
Publication Date(Web):2017/09/26
DOI:10.1039/C7RA09327F
The development of a multi-element synergistic flame-retardant depends largely on the design and synthesis of flame-retardants comprising a mixture of elements such as P, N and Si. Herein, we prepare a novel POSS derivative named octa-(N,N-(bis-(9,10-dihydro-9-oxa-10-phosphaphenanthene-10-yl)methyl)aminopropyl) silsesquioxane (ODMAS) that features a high content of P. The chemical structure of ODMAS was confirmed by FT-IR, 1H NMR, 29Si NMR, 31P NMR and elemental analysis. Because of the excellent compatibility between ODMAS and epoxy resin, the as-prepared ODMAS/EP composites are highly transparent as well as possessing improved flame-retardancy and mechanical properties. The results show that the LOI value reaches 37.1% with a low phosphorus content (1.6 wt%), samples only 5 wt% loading are classified with the V0 rating in the UL-94 test, and the char yield significantly increased and the maximum weight loss rate decreased with increased ODMAS loading. Results of a three-point bending test show that the flexural modulus of ODMAS/EP is higher than that of the pure epoxy resin. All results indicate that this novel flame retardant not only has good solubility in the polymer matrix, but can also simultaneously improve the flame resistance and mechanical properties of the polymeric material.
Co-reporter:Ying Chang, Conghui Yuan, Cheng Liu, Jie Mao, Yuntong Li, Haiyang Wu, Yuzhe Wu, Yiting Xu, Birong Zeng, Lizong Dai
Journal of Power Sources 2017 Volume 365(Volume 365) pp:
Publication Date(Web):15 October 2017
DOI:10.1016/j.jpowsour.2017.08.106
•A supramolecular route to fabricate carbon precursor with tunable B, N contents.•Synergistic effect of morphology, component and specific surface area was studied.•Excellent capacitance, rate capability and stability were obtained.•High activity, good methanol tolerance and durability for ORR were achieved.A novel strategy has been developed to generate B, N co-doped carbon materials (CNBs) through the pyrolysis of boronate polymer nanoparticles (BPNs) derived from the condensation reaction between catechol and boronic monomers. The morphology, surface area and heteroatom (viz. B and N) content of the CNBs can be easily adjusted by altering the molar ratio between catechol and boronic monomers. The supercapacitor and oxygen reduction reaction (ORR) performance of the CNBs are optimized. CNBs derived from equal molar ratio of catechol and boronic monomers exhibit favorable performance for supercapacitor, featuring a specific capacitance of up to 299.4 F/g at 0.2 A/g, an improved rate capability and excellent cycle stability. Notably, CNBs prepared using 1/2 molar ratio of catechol to boronic monomers show excellent ORR performance, as they demonstrate good electrocatalytic activity, high tolerance for methanol and long durability. Our findings may be of interest in the design of carbon materials with optimized electrochemical properties through the control over surface area and the content of heteroatom.B, N co-doped carbons derived from boronate polymer precursors exhibit improved supercapacitor and ORR properties.Download high-res image (373KB)Download full-size image
Co-reporter:C. Liu, T. Chen, C. H. Yuan, C. F. Song, Y. Chang, G. R. Chen, Y. T. Xu and L. Z. Dai
Journal of Materials Chemistry A 2016 vol. 4(Issue 9) pp:3462-3470
Publication Date(Web):25 Jan 2016
DOI:10.1039/C5TA07115A
In order to develop a multi-element, synergistic, flame-retardant system, the combination of DOPO, POM and POSS was achieved using the classical Kabachnik–Fields reaction. The as-designed POSS-bisDOPO was characterized by FT-IR, 1H NMR, 13C NMR, 31P NMR, 2D NMR, and MS. POSS-bisDOPO was introduced into epoxy resins to obtain flame-retardant materials. The LOI value can reach 34.5% when the content of POSS-bisDOPO is 20 wt%. The TGA results showed that the char yield was significantly improved in cured POSS-bisDOPO/EP. The ATR-FTIR results, optical images and SEM analyses indicated that the residual char had a compact and coherent appearance in the inner layer, while the outer structure was intumescent and multi-porous. Therefore, by isolating heat and oxygen more efficiently, the char played an important role in improving the thermal stability and flame retardancy of cured POSS-bisDOPO/EP. The three-point bending test results showed that the mechanical strength of POSS-bisDOPO/EP was higher than those of pure EP and POSS–NH2/EP due to the outstanding reinforcement effect of the unique nanostructure of POSS-bisDOPO assembled in the EP matrix. These data indicated that POSS-bisDOPO not only obviously enhances the flame retardancy, but also improves the mechanical properties of epoxy resins.
Co-reporter:Cong Xie;Jifu Du;Zhen Dong;Shaofa Sun;Long Zhao
Polymer Engineering & Science 2016 Volume 56( Issue 4) pp:441-447
Publication Date(Web):
DOI:10.1002/pen.24270
A new reactive phosphorus-containing curing agent with imine linkage called 4, 4′-[1, 3-phenyl-bis(9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-yl)dimethyneimino)]diphenol (2) was synthesized both via two-pot and one-pot procedure. The chemical structure of this curing agent was confirmed by FTIR, 1H, 13C, and 31P NMR spectra. A series of thermosetting systems were prepared by using conventional epoxy resins (E51), 4, 4′-diaminodiphenyl methane (DDM) and (2). Resins with different phosphorus contents were obtained by changing the DDM/(2) molar ratios. Their dynamic mechanical thermal, thermal and flame-retardant properties were evaluated by dynamic mechanical thermal analysis (DMTA), thermogravimetric analysis (TGA), and limiting oxygen index (LOI), respectively. All samples had a single Tg, which showed that these epoxy resins were homogeneous phase. Both the two char yields under nitrogen and air atmospheres increased with increasing content of (2) and the LOI values increased from 24.5 for standard resin to 37.5 for phosphorus-containing resin, which indicated that incorporation of (2) could impart good thermal stability and excellent flame retardancy to the conventional epoxy thermosets. POLYM. ENG. SCI., 56:441–447, 2016. © 2016 Society of Plastics Engineers
Co-reporter:Cunfeng Song, Shirong Yu, Cheng Liu, Yuanming Deng, Yiting Xu, Xiaoling Chen, Lizong Dai
Materials Science and Engineering: C 2016 Volume 62() pp:45-52
Publication Date(Web):1 May 2016
DOI:10.1016/j.msec.2016.01.026
•A novel macro-RAFT agent with ZC(S)SR was used for preparing graft copolymer.•P(MMA-co-HEMA)-g-PNIPAAm was successful prepared via the “grafting from” approach.•Thermo-responsibility of the P(MMA-co-HEMA)-g-PNIPAAm micelles was investigated.•The drug release behavior of the P(MMA-co-HEMA)-g-PNIPAAm micelles was studied.•These micelles exhibited excellent biocompatibility and cellular uptake property.A methodology to prepare thermo-responsive graft copolymer by using a novel macro-RAFT agent was proposed. The macro-RAFT agent with pendant dithioester (ZC(S)SR) was facilely prepared via the combination of RAFT polymerization and esterification reaction. By means of ZC(S)SR-initiated RAFT polymerization, the thermo-responsive graft copolymer consisting of poly(methyl methacrylate-co-hydroxylethyl methacrylate) (P(MMA-co-HEMA)) backbone and hydrophilic poly(N-isopropylacrylamide) (PNIPAAm) side chains was constructed through the “grafting from” approach. The chemical compositions and molecular weight distributions of the synthesized polymers were respectively characterized by 1H nuclear magnetic resonance (1H NMR) and gel permeation chromatography (GPC). Self-assembly behavior of the amphiphilic graft copolymers (P(MMA-co-HEMA)-g-PNIPAAm) was studied by transmission electron microscopy (TEM), dynamic light scattering (DLS) and spectrofluorimeter. The critical micelle concentration (CMC) value was 0.052 mg mL− 1. These micelles have thermo-responsibility and a low critical solution temperature (LCST) of 33.5 °C. Further investigation indicated that the guest molecule release property of these micelles, which can be well described by a first-order kinetic model, was significantly affected by temperature. Besides, the micelles exhibited excellent biocompatibility and cellular uptake property. Hence, these micelles are considered to have potential application in controlled drug delivery.
Co-reporter:Conghui Yuan, Ying Chang, Jie Mao, Shirong Yu, Weiang Luo, Yiting Xu, S. Thayumanavan and Lizong Dai
Journal of Materials Chemistry A 2015 vol. 3(Issue 14) pp:2858-2866
Publication Date(Web):18 Feb 2015
DOI:10.1039/C4TB01880J
Intermolecular B–N coordination has been recognized as a promising driving force for molecular self-organization. However, direct utilization of this intermolecular interaction as a building bridge for the supramolecular self-assembly of chemical functionalities to form nano-sized architectures remains a daunting challenge. Here, we outline a multiple intermolecular B–N coordination based supramolecular system, where small boronate molecules can be brought together in solution to form nanoparticles with controllable sizes and morphologies. We not only demonstrate the intrinsic switchable fluorescence and the stimuli-responsive capabilities of designed boronate molecules, but also show that the stabilized or surface functionalized nanoparticles are degradable in response to pH and D-glucose and able to retain the fluorescence features of the boronate molecules. Additionally, the degraded nanoparticles can repair themselves through the reformation of B–N coordination.
Co-reporter:Yang Li, Jinyan Lin, Yu Huang, Yanxiu Li, Xiangrui Yang, Hongjie Wu, Shichao Wu, Liya Xie, Lizong Dai, and Zhenqing Hou
ACS Applied Materials & Interfaces 2015 Volume 7(Issue 46) pp:25553
Publication Date(Web):November 3, 2015
DOI:10.1021/acsami.5b07348
We constructed 10-hydroxycamptothecin (CPT) “nanodrugs” with functionalization of lipid-PEG-methotrexate (MTX) to prepare high-drug-loaded, and sustained/controlled-release MTX-PEG-CPT nanorods (NRs), in which MTX drug itself can serve as a specific “targeting ligand”. The self-targeted nanodrug can codeliver both CPT and MTX drugs with distinct anticancer mechanisms. Furthermore, MTX-PEG-CPT NRs significantly reduced burst release, improved blood circulation and tumor accumulation, enhanced cellular uptake, and synergistically increased anticancer effect against tumor cells compared with MTX-PEG-CPT nanospheres (NSs) and either both free drugs or individual free drug. Therefore, the synergistic targeting/therapeuticy nano-multi-drug codelivery assisted by shape design may advantageously offer a promising new strategy for nanomedicine.Keywords: DSPE-PEG-MTX; nanodrug; self-targeted drug delivery; sustain/controlled drug release; synergistic anticancer activity
Co-reporter:Yang Li, Jinyan Lin, Xiangrui Yang, Yanxiu Li, Shichao Wu, Yu Huang, Shefang Ye, Liya Xie, Lizong Dai, and Zhenqing Hou
ACS Applied Materials & Interfaces 2015 Volume 7(Issue 32) pp:17573
Publication Date(Web):August 3, 2015
DOI:10.1021/acsami.5b05038
Integrating advantages of mitomycin C (MMC)–phospholipid complex for increased drug encapsulation efficiency and reduced premature drug release, DSPE-PEG-folate (DSPE-PEG-FA) for specific tumor targeting, we reported a simple one-pot self-assembly route to prepare the MMC–phospholipid complex-loaded DSPE-PEG-based nanoparticles (MP-PEG-FA NPs). Both confocal imaging and flow cytometry demonstrated that MMC was distributed into nuclei after cellular uptake and intracellular drug delivery. More importantly, the systemically administered MP-PEG-FA NPs led to increased blood persistence and enhanced tumor accumulation in HeLa tumor-bearing nude mice. This study introduces a simple and effective strategy to design the anticancer drug–phospholipid complex-based targeted drug delivery system for sustained/controlled drug release.Keywords: anticancer-phospholipid complex; nanoparticles; self-assembly; sustained/controlled drug release; targeted drug delivery
Co-reporter:C. Yuan, J. Chen, S. Yu, Y. Chang, J. Mao, Y. Xu, W. Luo, B. Zeng and L. Dai
Soft Matter 2015 vol. 11(Issue 11) pp:2243-2250
Publication Date(Web):26 Jan 2015
DOI:10.1039/C4SM02528H
Supramolecular self-assembly driven by catechol–metal ion coordination has gained great success in the fabrication of functional materials including adhesives, capsules, coatings and hydrogels. However, this route has encountered a great challenge in the construction of nanoarchitectures in the absence of removable templates, because of the uncontrollable crosslinking of catechol–metal ion coordination. Herein, we show that a supramolecular approach, combining both catechol–metal ion coordination and polymer self-assembly together, can organize polymers into hybrid nanoassemblies ranging from solid particles, homogeneous vesicles to Janus vesicles. Without the introduction of a specific binding ligand or complicated molecular design, these assemblies can totally disassemble in response to proteins. UV/vis absorption, fluorescence quenching and recovery investigations have confirmed that proteins can seize metal ions from the hybrid nanoassemblies, thus causing the degradation of catechol–metal ion coordination networks.
Co-reporter:Yang Li; Jinyan Lin; Hongjie Wu; Ying Chang; Conghui Yuan; Cheng Liu; Shuang Wang; Zhenqing Hou
Molecular Pharmaceutics 2015 Volume 12(Issue 3) pp:769-782
Publication Date(Web):January 27, 2015
DOI:10.1021/mp5006068
The design of nanoscale drug delivery systems for the targeted codelivery of multiple therapeutic drugs still remains a formidable challenge (ACS Nano, 2013, 7, 9558–9570; ACS Nano, 2013, 7, 9518–9525). In this article, both mitomycin C (MMC) and methotrexate (MTX) loaded DSPE-PEG micelles (MTX–M–MMC) were prepared by self-assembly using the dialysis technique, in which MMC–soybean phosphatidylcholine complex (drug–phospholipid complex) was encapsulated within MTX-functionalized DSPE-PEG micelles. MTX–M–MMC could coordinate an early phase active targeting effect with a late-phase synergistic anticancer effect and enable a multiple-responsive controlled release of both drugs (MMC was released in a pH-dependent pattern, while MTX was released in a protease-dependent pattern). Furthermore, MTX–M–MMC could codeliver both drugs to significantly enhance the cellular uptake, intracellular delivery, cytotoxicity, and apoptosis in vitro and improve the tumor accumulation and penetration and anticancer effect in vivo compared with either both free drugs treatment or individual free drug treatment. To our knowledge, this work provided the first example of the systemically administrated, orthogonally functionalized, and self-assisted nanoscale micelles for targeted combination cancer chemotherapy. The highly convergent therapeutic strategy opened the door to more simplified, efficient, and flexible nanoscale drug delivery systems.
Co-reporter:Yiting Xu;Jianjie Xie;Hui Gao;Ying Cao;Min Chen;Yanling Liu
Macromolecular Research 2015 Volume 23( Issue 1) pp:2-12
Publication Date(Web):2015 January
DOI:10.1007/s13233-015-3012-6
Co-reporter:Conghui Yuan, Kishore Raghupathi, Bhooshan C. Popere, Judy Ventura, Lizong Dai and S. Thayumanavan
Chemical Science 2014 vol. 5(Issue 1) pp:229-234
Publication Date(Web):26 Sep 2013
DOI:10.1039/C3SC52347K
Nanoscale assemblies with stimuli-sensitive features have attracted significant attention due to implications in a variety of areas ranging from materials to biology. Recently, there have been excellent developments in obtaining nanoscale structures that are concurrently sensitive to multiple stimuli. Such nanostructures are primarily focused on a single nanostructure containing an appropriate combination of functional groups within the nanostructure. In this work, we outline a simple approach to bring together two disparate supramolecular assemblies that exhibit very different stimuli-sensitive characteristics. These composite nanostructures comprise a block copolymer micelle core and nanogel shell, both of which can preserve their respective morphology and stimulus sensitivities. The block copolymer is based on poly(2-(diisopropylamino)ethylmethacrylate-b-2-aminoethylmethacrylate hydrochloride), which contains a pH-sensitive hydrophobic block. Similarly, the redox-sensitive nanogel is derived from a poly(oligoethyleneglycolmonomethylethermethacrylate-co-glycidylmethacrylate-co-pyridyldisulfide ethylmethacrylate) based random copolymer. In addition to the independent pH-response of the micellar core and redox-sensitivity of the nanogel shell in the composite nanostructures, the synergy between the micelles and the nanogels have been demonstrated through a robust charge generation in the nanogels during the disassembly of the micelles. The supramolecular assembly and disassembly have been characterized using transmission electron microscopy, dynamic light scattering, zeta potential measurements, fluorescence spectroscopy and cellular uptake.
Co-reporter:Yang Li, Jinyan Lin, Hongjie Wu, Mengmeng Jia, Conghui Yuan, Ying Chang, Zhenqing Hou and Lizong Dai
Journal of Materials Chemistry A 2014 vol. 2(Issue 38) pp:6534-6548
Publication Date(Web):01 Aug 2014
DOI:10.1039/C4TB00499J
In the present study we have investigated novel MTX prodrug-targeted and MMC-loaded PLA–lipid–PEG hybrid NPs. These employ a double emulsion solvent evaporation method for the introduction of an anticancer drugs moiety of the MMC–soybean phosphatidylcholine complex or DSPE–PEG–MTX, in which the MTX prodrug can be exploited as a targeting ligand. The prepared drug delivery systems present a spherical shape, a small particle size (219.6 ± 2.1 nm) with narrow particle size distribution, high MMC encapsulation efficiency (90.5 ± 3.0%) and a sustained and pH-controlled MMC release. The advantage of the new drug delivery systems is that the two-anticancer drug moiety can coordinate the early-phase targeting effect with the later-phase anticancer effect. In vivo pharmacokinetics, following intravenous administration of the drug delivery systems, indicates a prolonged systemic circulation time of MMC. More importantly, the drug delivery systems exhibited a significant accumulation of MMC in the nuclei as the site of MMC action, which was indicative of the enhancement of anticancer activity. Such a design of drug delivery systems may open up a new horizon for targeted delivery and sustained and controlled release of MMC.
Co-reporter:Conghui Yuan, Birong Zeng, Shirong Yu, Jie Mao, Xiaoling Chen, Weiang Luo, Yiting Xu, Feng-Chih Chang and Lizong Dai
RSC Advances 2014 vol. 4(Issue 10) pp:4796-4803
Publication Date(Web):10 Dec 2013
DOI:10.1039/C3RA45758C
A facile and large-scale method combining airflow-controlled solvent evaporation and amphiphilic copolymer self-assembly has been developed for the generation of hollow polymer microspheres, colloidosomes or even organic–inorganic hybrid colloidosomes. By replacing traditional agitation with the controllable airflow, this surfactant free route showed promising prospect in the fabrication of microcapsules with closed pore morphology. While the hollow polymer microspheres had an adjustable pore structure, the polymer colloidosomes and the hybrid colloidosomes possessed seamless surfaces, making them suitable for the stable encapsulation of small molecules. The hybrid colloidosomes constructed from polymer and Fe3O4 nanoparticles, and the ternary hybrid colloidosomes derived from polymer, polymer nanospheres and Fe3O4 nanoparticles displayed superparamagnetic properties and were excellent contrast agents for magnetic resonance imaging. More importantly, both hybrid colloidosomes and ternary hybrid colloidosomes exhibited a significant evolution of pore morphology from a closed pore structure to an open pore structure in response to the temperature variation, which induced a controllable release of guest molecules.
Co-reporter:Lingnan Chen;Birong Zeng;Yueguang Wu;Jianjie Xie;Shirong Yu;Conghui Yuan;Weiang Luo;Yiting Xu
Polymers for Advanced Technologies 2014 Volume 25( Issue 9) pp:1069-1076
Publication Date(Web):
DOI:10.1002/pat.3352
Magnetic composite nanospheres (MCS) were first prepared via mini-emulsion polymerization. Subsequently, the hybrid core–shell nanospheres were used as carriers to support gold nanoparticles. The as-prepared gold-loading magnetic composite nanospheres (Au-MCS) had a hydrophobic core embed with γ-Fe3O4 and a hydrophilic shell loaded by gold nanoparticles. Both the content of γ-Fe3O4 and the size of gold nanoparticles could be controlled in our experiments, which resulted in fabricating various materials. On one hand, the Au-MCS could be used as a T2 contrast agent with a relaxivity coefficient of 362 mg−1 ml S−1 for magnetic resonance imaging. On the other hand, the Au-MCS exhibited tunable optical-absorption property over a wavelength range from 530 nm to 800 nm, which attributed to a secondary growth of gold nanoparticles. In addition, dynamic light scattering results of particle sizing and Zeta potential measurements revealed that Au-MCS had a good stability in an aqueous solution, which would be helpful for further applications. Finally, it showed that the Au-MCS were efficient catalysts for reductions of hydrophobic nitrobenzene and hydrophilic 4-nitrophenol that could be reused by a magnetic separation process. Copyright © 2014 John Wiley & Sons, Ltd.
Co-reporter:Cong Xie;Birong Zeng;Hui Gao;Yiting Xu;Weiang Luo;Xinyu Liu
Polymer Engineering & Science 2014 Volume 54( Issue 5) pp:1192-1200
Publication Date(Web):
DOI:10.1002/pen.23642
In an attempt to improve thermal and flame-retardant properties of epoxy resins efficiently, a new reactive phosphorus-containing curing agent called 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-yl-(phenylimino)-(4-hydroxyphenyl)me-thane (DOPO-PHM) was synthesized and was combined with 4,4′-diaminodiphenyl methane (DDM) to co-cure epoxy resins (E51), which covalently incorporated halogen-free DOPO organ groups into the epoxy networks. The chemical structure of this curing agent was confirmed by FTIR, 1D, and 2D NMR spectra. A reaction mechanism during the preparation was proposed, and the electron effect on the stabilization of the carbocation was discussed. Various DDM/DOPO-PHM molar ratios were used to get the materials with different phosphorus contents. Their dynamic mechanical, thermal, and flame-retardant properties were evaluated by dynamic mechanical thermal analysis, thermogravimetric analysis, and limiting oxygen index (LOI) respectively. All samples had a single Tg, showing that these epoxy resins were homogeneous phase for long-term use in spite of adding DOPO-PHM. Both char yields (under nitrogen and air atmospheres) increased with the increasing of phosphorus content and the LOI values increased from 24.5 for standard resin to 33.5 for phosphorus-containing resins, indicating the significant enhancement of thermal stability and flame retardancy. POLYM. ENG. SCI., 54:1192–1200, 2014. © 2013 Society of Plastics Engineers
Co-reporter:Cunfeng Song, Ying Chang, Ling Cheng, Yiting Xu, Xiaoling Chen, Long Zhang, Lina Zhong, Lizong Dai
Materials Science and Engineering: C 2014 Volume 36() pp:146-151
Publication Date(Web):1 March 2014
DOI:10.1016/j.msec.2013.11.042
•A new type of antibacterial agent (PSA/Ag-NPs nanocomposites) was synthesized.•The antibacterial activity against S. aureus and E. coli was studied.•Inhibition zone, MIC, MBC, and bactericidal kinetics were evaluated.•PSA/Ag-NPs nanocomposites showed excellent antibacterial activity.A simple method for preparing a new type of stable antibacterial agent was presented. Monodisperse poly(styrene-co-acrylic acid) (PSA) nanospheres, serving as matrices, were synthesized via soap-free emulsion polymerization. Field-emission scanning electron microscopy micrographs indicated that PSA nanospheres have interesting surface microstructures and well-controlled particle size distributions. Silver-loaded poly(styrene-co-acrylic acid) (PSA/Ag-NPs) nanocomposites were prepared in situ through interfacial reduction of silver nitrate with sodium borohydride, and further characterized by transmission electron microscopy and X-ray diffraction. Their effects on antibacterial activity including inhibition zone, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and bactericidal kinetics were evaluated. In the tests, PSA/Ag-NPs nanocomposites showed excellent antibacterial activity against both gram-positive Staphylococcus aureus and gram-negative Escherichia coli. These nanocomposites are considered to have potential application in antibacterial coatings on biomedical devices to reduce nosocomial infection rates.
Co-reporter:Shengchao Jiang, Lingxing Zhang, Tingwan Xie, Yangju Lin, Huan Zhang, Yuanze Xu, Wengui Weng, and Lizong Dai
ACS Macro Letters 2013 Volume 2(Issue 8) pp:705
Publication Date(Web):July 24, 2013
DOI:10.1021/mz400198n
A mechanically active spiropyran (SP) mechanophore is incorporated into the center of poly(n-butyl acrylate) (PnBA) block to construct a series of mechanoresponsive polystyrene (PS)-PnBA-SP-PnBA-PS triblock copolymers. Similar mechanical activations of SP occur in all of the copolymers in solution, whereas a unique PS fraction-dependent mechanochromism is observed in the bulk. Effective mechanical activation occurs in the copolymer with a medium PS block length, whereas a very weak color change is observed in the samples bearing low PS fractions and activation appears only in the vicinity of the fracture point in the copolymer bearing long PS blocks. The difference in chemical compositions of the triblock copolymers leads to different microphase separated structures in the bulk and consequently the unique stress–strain responses and mechanochemistry. This platform promises to open way to the design of a wide range of useful mechanoresponsive triblock copolymers having different hard/soft blocks and various types of mechanoresponsive motifs.
Co-reporter:Jun Dong;Jiabao Ding;Jian Weng
Macromolecular Rapid Communications 2013 Volume 34( Issue 8) pp:659-664
Publication Date(Web):
DOI:10.1002/marc.201200814
Co-reporter:Yiting Xu;Jianjie Xie;Lingnan Chen;Conghui Yuan;Yinyin Pan
Macromolecular Research 2013 Volume 21( Issue 12) pp:1338-1348
Publication Date(Web):2013 December
DOI:10.1007/s13233-013-1185-4
Co-reporter:Lingnan Chen, Birong Zeng, Jianjie Xie, Shirong Yu, Conghui Yuan, Yinyin Pan, Weiang Luo, Xinyu Liu, Kaibin He, Yiting Xu, Lizong Dai
Reactive and Functional Polymers 2013 73(8) pp: 1022-1029
Publication Date(Web):August 2013
DOI:10.1016/j.reactfunctpolym.2013.05.005
Co-reporter:Yuanming Deng;Cangjie Yang;Conghui Yuan;Yiting Xu;Julien Bernard;Jean-François Gérard
Journal of Polymer Science Part A: Polymer Chemistry 2013 Volume 51( Issue 21) pp:4558-4564
Publication Date(Web):
DOI:10.1002/pola.26872
ABSTRACT
A simple route to organic–inorganic (O/I) nano-objects with different morphologies through polymerization-induced block copolymer self-assembly is described. The synthetic strategy relies on the chain-extension of polyhedral oligomeric silsesquioxanes (POSS)-containing macro-CTA (PMAiBuPOSS13 and PMAiBuPOSS19) with styrene at 120 °C in octane, a selective solvent of the POSS-containing block. The polymerization system was proven to afford a plethora of O/I nano-objects, such as spherical micelles, cylindrical micelles, and vesicles depending on the respective molar masses of the PMAiBuPOSS and polystyrene (PS) blocks. The cooling procedure was also proven to be a crucial step to generate particles with a unique morphology. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 4558–4564
Co-reporter:Yiting Xu, Min Chen, Jianjie Xie, Cong Li, Cangjie Yang, Yuanming Deng, Conghui Yuan, Feng-Chih Chang, Lizong Dai
Reactive and Functional Polymers 2013 73(12) pp: 1646-1655
Publication Date(Web):December 2013
DOI:10.1016/j.reactfunctpolym.2013.09.008
Co-reporter:Conghui Yuan, Lina Zhong, Cangjie Yang, Guangjian Chen, Binjie Jiang, Yuanming Deng, Yiting Xu, Weiang Luo, Birong Zeng, Jie Liu and Lizong Dai
Journal of Materials Chemistry A 2012 vol. 22(Issue 15) pp:7108-7112
Publication Date(Web):12 Mar 2012
DOI:10.1039/C2JM16578C
3D Au nanodendrimers constructed by radially arranged thin nano-sheets show tunable morphology and diameter. The unexpectedly large specific surface area resulting from the novel porous nanostructure makes the 3D Au nanodendrimers exhibit high catalytic activity and long service life.
Co-reporter:Cangjie Yang;Yuanming Deng;Birong Zeng;Conghui Yuan;Min Chen;Weiang Luo;Jie Liu;Yiting Xu
Journal of Polymer Science Part A: Polymer Chemistry 2012 Volume 50( Issue 20) pp:4300-4310
Publication Date(Web):
DOI:10.1002/pola.26237
Abstract
In this article, the amphiphilic block copolymers containing polyhedral oligomeric silsesquioxane (POSS), namely PMAPOSS-b-PAA and PMAPOSS-b-P(AA-co-St), were synthesized consecutively by reversible addition–fragmentation chain transfer and selective hydrolysis, and characterized by 1H NMR, 13C NMR, Fourier transform infrared spectroscopy and gel permeation chromatography. In the presence of the nearly gradient styrene distribution along the hydrophilic block with a feed molar ratio of tert-butyl acrylate (tBA) to St being 10/1, patterned core-corona nanoparticles (NPs) were formed from the mixture of good/selective solvents (THF/water) by a simple evaporation process at room temperature. With the extending of the co-block length, the self-assembled NPs exhibited phase separation behavior of spheres-dispersed, onion-like and onion-cluster hierarchical structures in turn. However, while a change in the feed molar ratio occurred, it resulted in the formation of typical core-shell micelles (20/1, tBA/St) and disordered particles (5/1, tBA/St), respectively. Furthermore, the self-assembly behavior of PMAPOSS-b-P(AA-co-St) in DMF was investigated, which showed that it could perform a mixture morphology of well-dispersive sphere micelles and large aggregate of micelles. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Co-reporter:Conghui Yuan, Yiting Xu, Nina Jiang, Guangjian Chen, Binbin Xu, Ning He
and Lizong Dai
Soft Matter 2011 vol. 7(Issue 7) pp:3366-3372
Publication Date(Web):14 Feb 2011
DOI:10.1039/C0SM01128B
Colloidosomes constructed by the self-assembly of nanoparticles (NPs) on liquid–liquid interfaces have been demonstrated to be useful in many fields. However, the interspaces between NPs on the surface of colloidosomes barricade their application in small molecule encapsulation. Herein, fabrication of a new type of colloidosome built by the seamless connection of NPs via simply heating and quenching a type of core–shell structured NPs (CSNPs) aqueous system using oil as a template, is presented. These colloidosomes have a hollow structure and exhibit efficient small molecule encapsulation. More importantly, the colloidosomes can dissociate into single NPs and release the small target molecules encapsulated in interior of the colloidosomes at a temperature higher than the melting point of the CSNP shell. It is also shown that the dissociation temperature of colloidosomes can be controlled by simply adjusting the length of the PEG chains in the CSNP shell, which implies that these intelligent capsules have attractive application prospects in controlled drug release.
Co-reporter:Yiting Xu, Yingying Ma, Yuanming Deng, Cangjie Yang, Jiangfeng Chen, Lizong Dai
Materials Chemistry and Physics 2011 Volume 125(1–2) pp:174-183
Publication Date(Web):1 January 2011
DOI:10.1016/j.matchemphys.2010.09.003
Monofunctional-anhydride polyhedral oligomeric silsesquioxane (i-C4H9)7Si8O12OSi(CH3)2(C8H9O3) (AH-POSS) was synthesized and characterized by FTIR, NMR, element analysis. Then AH-POSS was incorporated into epoxy system either pre-reacted or non-reacted using hexahydrophthalic anhydride (HHPA) as curing agent. Pre-reacted system hybrid materials were obtained by two-step preparation. First, AH-POSS reacted with part of diglycidyl ether of bisphenol A (DGEBA) to form AH-POSS-epoxy precursor in DGEBA, then cured with HHPA. Non-reacted POSS/epoxy hybrid materials were prepared by directly mixing AH-POSS, HHPA and DGEBA together and cured afterwards. The GPC and FTIR spectra suggested successful bonding of AH-POSS and epoxy resin. Morphologies of hybrid materials were characterized by SEM and TEM. Non-reacted system led to a dispersion of spherical particles with sizes in the range of micrometers. For pre-reacted system, polymerization-induced phase separation took place with POSS content lower than 30 wt% and also some “vesicle” structure was formed after curing. A typical macro-phase separation happened with POSS content up to 40 wt% before and after curing. The glass transition temperatures (Tg's) and the storage modulus were measured by dynamic mechanical analysis (DMA). Tg's and modulus displayed irregularly decrease. The initial thermal decomposition temperatures (Td's) characterized by TGA were also irregularly decreasing for both systems. However, they were higher than those of epoxy composites when using amine as the curing agent.
Co-reporter:Wenjun Xiao;Jie Liu;Qin Chen;Ying Wu;Tinghua Wu
Crystal Research and Technology 2011 Volume 46( Issue 10) pp:1071-1078
Publication Date(Web):
DOI:10.1002/crat.201100261
Abstract
Gel–forming fibers (GF fibers) can serve as nucleation sites to prepare calcium carbonate (CaCO3) because they can adsorb large amounts of Ca2+ due to their porous structure. In this paper, mineralization behavior of CaCO3 on GF fibers in ethanol–water mixed solvents without any additives has been investigated. The results showed that some crystals covered the fibers, while others were embedded in fibers. Twin–sphere based vaterite, zonary and rodlike calcite with large aspect ratio could be prepared successfully. The effect of ethanol content inside GF fibers, concentration of Ca2+ and CO32-, mineralization time, miscibility between alcohol and water, and temperature were studied. Lastly, a possible mineralization mode was suggested. This work could provide a new method to prepare inorganic/polymer hybrid materials. (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Co-reporter:Dr. Conghui Yuan;Dr. Weiang Luo;Lina Zhong;Hujun Deng;Dr. Jie Liu; Yiting Xu; Lizong Dai
Angewandte Chemie International Edition 2011 Volume 50( Issue 15) pp:3515-3519
Publication Date(Web):
DOI:10.1002/anie.201007077
Co-reporter:Conghui Yuan, Yiting Xu, Yifu Liao, Sujuan Lin, Ning He and Lizong Dai
Journal of Materials Chemistry A 2010 vol. 20(Issue 44) pp:9968-9975
Publication Date(Web):24 Sep 2010
DOI:10.1039/C0JM02023K
A novel type of waist cross-linked micelle (WCM) was developed as an intelligent drug carrier via the self-assembly guiding free radical polymerization of an amphiphilic oligomer: octadecyl, polyethylene glycol butenedioates (O–B–EGs). By changing the concentration of O–B–EG reaction solution, WCMs with monolayer, compound and vesicle-like morphologies were obtained. These WCMs showed controllable temperature responsive properties. DLS and UV-vis analyses indicate that the critical temperatures at which WCMs show an abrupt change in particle size evidently increases with the increase in the molecular weight of the PEG chains. Direct switching of the release of pyrene in WCMs is also realized by a slight change of temperature. Pyrene is released rapidly at the temperatures around the critical temperature of the WCMs, but a further increase in temperature shuts down the release of pyrene. More importantly, these WCMs exhibit reversible and rapid pyrene releasing-absorbing behavior. We suggest that these excellent properties endow WCMs with great potential in drug encapsulation and controlled release
Co-reporter:Nina Jiang, Yiting Xu, Ning He, Jiangfeng Chen, Yuanming Deng, Conghui Yuan, Guobin Han and Lizong Dai
Journal of Materials Chemistry A 2010 vol. 20(Issue 48) pp:10847-10855
Publication Date(Web):12 Oct 2010
DOI:10.1039/C0JM01705A
Walnut-like structures made up of a polyaniline (PANI) nanofiber network and polystyrene (PS) microspheres are successfully fabricated by a novel approach, “competitive adsorption–restricted polymerization”. In the reaction system, PS microspheres are simultaneously encapsulated by cationic surfactant and aniline hydrochloride. Just this cationic surfactant molecule affects the nucleation model and second growth of PANI via electrostatic interactions and steric hindrance, which accounts for the formation of a PANI nanofiber network coating on the PS surface. The size, ordering and amount of PANI nanofibers on the three-dimensional surface can be particularly controlled by altering a variety of synthetic conditions, such as the amount of cationic surfactant, temperature and concentration. A superhydrophobic and conductive surface is obtained by drop-casting a suspension of these walnut-like PS/PANI particles onto a substrate.
Co-reporter:Wenjun Xiao, Qin Chen, Ying Wu, Tinghua Wu, Lizong Dai
Materials Chemistry and Physics 2010 Volume 123(Issue 1) pp:1-4
Publication Date(Web):1 September 2010
DOI:10.1016/j.matchemphys.2010.04.007
At low temperature, Mn-doped ZnO mesocrystals have been prepared in a hydrated ionic liquid precursor tetrabutylammonium hydroxide (TBAH). A clear hysteresis with coercive field Hc = 85 Oe and remanence Mr = 0.0213 emu g−1 was observed in Zn0.95Mn0.05O mesocrystals, but only paramagnetism was observed in Zn0.95Mn0.05O nanorods. The morphologies, structures, chemical state, optical properties and room temperature ferromagnetic properties of the synthesized Zn0.95Mn0.05O samples could be controlled simply by changing the concentration of zinc acetate in ionic liquid precursor.
Co-reporter:Bo Qu, Yi-Ting Xu, Su-juan Lin, Yi-Fang Zheng, Li-Zong Dai
Synthetic Metals 2010 Volume 160(7–8) pp:732-742
Publication Date(Web):April 2010
DOI:10.1016/j.synthmet.2010.01.012
Here we report the synthesis and characterization of a catalyst material constituted of Pt, polypyrrole (PPy) and multi-walled carbon nanotubes (MWNTs). The catalyst supports (PPy–MWNTs nanocomposites) were synthesized via in situ chemical polymerization in advance, in which MWNTs were regarded as the matrix material. The supports were characterized by SEM & TEM, elemental analysis, XRD, FTIR and conductivity measurements. Then the catalysts were synthesized by a chemical reduction using sodium borohydride (NaBH4) as reducing agent and acetic acid buffer (pH = 4) containing trace K2C2O4 as reaction media. FTIR spectra showed that there existed relations between PPy and MWNTs during in situ polymerization. SEM and TEM micrographs of the catalyst samples exhibited that the existence of PPy layer which was evenly wrapped on the surface of MWNTs resulted in significant improvement in helping Pt particles well dispersed. XRD results showed that higher Pt(1 1 1) content in the catalyst deposited on PPy–MWNTs supports than that on MWNTs. The cyclic voltammetry (CV) tests of methanol electrocatalytic oxidation demonstrated that the electrode modified by Pt/PPy–MWNTs ternary composite catalyst showed higher catalytic stability than Pt/MWNTs binary catalyst, due to the synergic interaction between Pt and the carrier.
Co-reporter:Conghui Yuan, Yiting Xu, Yuanming Deng, Jiangfeng Chen, Yanling Liu and Lizong Dai
Soft Matter 2009 vol. 5(Issue 23) pp:4642-4646
Publication Date(Web):19 Oct 2009
DOI:10.1039/B916290A
Amphiphilic micelles with waist cross-linked structure exhibit both core–shell reversing behavior and thermal sensitivity.
Co-reporter:Yiting Xu, Lizong Dai, Jiangfeng Chen, Jean-Yves Gal, Huihuang Wu
European Polymer Journal 2007 Volume 43(Issue 5) pp:2072-2079
Publication Date(Web):May 2007
DOI:10.1016/j.eurpolymj.2006.09.017
The copolymer of aniline (An) and aniline-o-sulfonic acid (AS) is synthesized by chemical oxidation polymerization. The effects of mole ratio of copolymerized monomers on chain structure, thermostability, conductivity, redox properties of copolymer are discussed. It is indicated that if more AS monomers in polymerization system the corresponding structure units will increase, but their relation isn’t linear. When An:AS = 1:1, the ratio of structure unit in copolymer is 9:1, and it is only 1:2 for copolymer with An:AS = 1:6. The measurements of conductivity and redox activity also prove that the properties of An-co-AS(1:1), (1:3), and (1:4) are similar to polyaniline due to more An units than AS. When An:AS is higher than 1:6, it shows out the properties of copolymer is similar to those of poly(aniline-o-sulfonic acid), and their redox route is different. They will transform to follow the route of LH ↔ EH ↔ P. The results of thermo-analysis indicate that the decomposition temperature of AS units is lower than An units because of the electron-withdrawing group substitution. The decomposition temperature of polymer is related to dopant and doping degree. Electron-withdrawing group, –SO3H, substitution and HCl doping will decrease polymer chain decomposition temperature. The mechanism of copolymerization of An and AS is different from homopolymerization. The monomer with low oxidation potential forms free radical cation firstly, which transfers to monomer with higher oxidation potential and initiates its polymerization.
Co-reporter:Lizong Dai;Yiting Xu;Yunyou He;Jean-Yves Gal;Huihuang Wu
Polymer International 2005 Volume 54(Issue 9) pp:
Publication Date(Web):20 MAY 2005
DOI:10.1002/pi.1838
The redox behavior of polyanilines with ring-substituted groups synthesized by chemical polymerization, poly-2,5-dimethoxyaniline (PDMAn), poly-m-chloroaniline (PmClAn) and poly-o-toluidine (POT), was studied and the morphology and crystal orientation of platinum particles deposited on these polymer membranes was compared. The oxidation of isopropanol on platinized polyaniline-modified electrodes as a model reaction was also investigated to examine the electrocatalytic properties of the polymers. The results show that the first oxidation potential of the polymers increases in the following sequence: PDMAn, POT and then PmClAn, which can be explained in terms of the electronic and steric effects of ring-substituted groups. The growth of Pt particles electrodeposited on doping-state POT and PDMAn polymer membranes takes place by a ‘progressive nucleation mechanism’, but by an ‘instantaneous nucleation mechanism’ on PmClAn. Platinum crystallites trend towards preferred-orientation and Pt (200) is the preferred face, but the degree of preferred orientation depends on the polymer. The oxidation potentials of isopropanol are located near 0.3 V, and the oxidation currents increase on platinized polymer-modified electrodes, indicating that the interaction of polymer with Pt particles might improve the catalytic activity of Pt. Polyanilines act not only as dispersion media but also change the electronic properties of Pt crystalline grains. Copyright © 2005 Society of Chemical Industry
Co-reporter:Conghui Yuan, Kishore Raghupathi, Bhooshan C. Popere, Judy Ventura, Lizong Dai and S. Thayumanavan
Chemical Science (2010-Present) 2014 - vol. 5(Issue 1) pp:NaN234-234
Publication Date(Web):2013/09/26
DOI:10.1039/C3SC52347K
Nanoscale assemblies with stimuli-sensitive features have attracted significant attention due to implications in a variety of areas ranging from materials to biology. Recently, there have been excellent developments in obtaining nanoscale structures that are concurrently sensitive to multiple stimuli. Such nanostructures are primarily focused on a single nanostructure containing an appropriate combination of functional groups within the nanostructure. In this work, we outline a simple approach to bring together two disparate supramolecular assemblies that exhibit very different stimuli-sensitive characteristics. These composite nanostructures comprise a block copolymer micelle core and nanogel shell, both of which can preserve their respective morphology and stimulus sensitivities. The block copolymer is based on poly(2-(diisopropylamino)ethylmethacrylate-b-2-aminoethylmethacrylate hydrochloride), which contains a pH-sensitive hydrophobic block. Similarly, the redox-sensitive nanogel is derived from a poly(oligoethyleneglycolmonomethylethermethacrylate-co-glycidylmethacrylate-co-pyridyldisulfide ethylmethacrylate) based random copolymer. In addition to the independent pH-response of the micellar core and redox-sensitivity of the nanogel shell in the composite nanostructures, the synergy between the micelles and the nanogels have been demonstrated through a robust charge generation in the nanogels during the disassembly of the micelles. The supramolecular assembly and disassembly have been characterized using transmission electron microscopy, dynamic light scattering, zeta potential measurements, fluorescence spectroscopy and cellular uptake.
Co-reporter:Conghui Yuan, Yiting Xu, Yifu Liao, Sujuan Lin, Ning He and Lizong Dai
Journal of Materials Chemistry A 2010 - vol. 20(Issue 44) pp:NaN9975-9975
Publication Date(Web):2010/09/24
DOI:10.1039/C0JM02023K
A novel type of waist cross-linked micelle (WCM) was developed as an intelligent drug carrier via the self-assembly guiding free radical polymerization of an amphiphilic oligomer: octadecyl, polyethylene glycol butenedioates (O–B–EGs). By changing the concentration of O–B–EG reaction solution, WCMs with monolayer, compound and vesicle-like morphologies were obtained. These WCMs showed controllable temperature responsive properties. DLS and UV-vis analyses indicate that the critical temperatures at which WCMs show an abrupt change in particle size evidently increases with the increase in the molecular weight of the PEG chains. Direct switching of the release of pyrene in WCMs is also realized by a slight change of temperature. Pyrene is released rapidly at the temperatures around the critical temperature of the WCMs, but a further increase in temperature shuts down the release of pyrene. More importantly, these WCMs exhibit reversible and rapid pyrene releasing-absorbing behavior. We suggest that these excellent properties endow WCMs with great potential in drug encapsulation and controlled release
Co-reporter:C. Liu, T. Chen, C. H. Yuan, C. F. Song, Y. Chang, G. R. Chen, Y. T. Xu and L. Z. Dai
Journal of Materials Chemistry A 2016 - vol. 4(Issue 9) pp:NaN3470-3470
Publication Date(Web):2016/01/25
DOI:10.1039/C5TA07115A
In order to develop a multi-element, synergistic, flame-retardant system, the combination of DOPO, POM and POSS was achieved using the classical Kabachnik–Fields reaction. The as-designed POSS-bisDOPO was characterized by FT-IR, 1H NMR, 13C NMR, 31P NMR, 2D NMR, and MS. POSS-bisDOPO was introduced into epoxy resins to obtain flame-retardant materials. The LOI value can reach 34.5% when the content of POSS-bisDOPO is 20 wt%. The TGA results showed that the char yield was significantly improved in cured POSS-bisDOPO/EP. The ATR-FTIR results, optical images and SEM analyses indicated that the residual char had a compact and coherent appearance in the inner layer, while the outer structure was intumescent and multi-porous. Therefore, by isolating heat and oxygen more efficiently, the char played an important role in improving the thermal stability and flame retardancy of cured POSS-bisDOPO/EP. The three-point bending test results showed that the mechanical strength of POSS-bisDOPO/EP was higher than those of pure EP and POSS–NH2/EP due to the outstanding reinforcement effect of the unique nanostructure of POSS-bisDOPO assembled in the EP matrix. These data indicated that POSS-bisDOPO not only obviously enhances the flame retardancy, but also improves the mechanical properties of epoxy resins.
Co-reporter:Ying Chang, Conghui Yuan, Yuntong Li, Cheng Liu, Tong Wu, Birong Zeng, Yiting Xu and Lizong Dai
Journal of Materials Chemistry A 2017 - vol. 5(Issue 4) pp:NaN1678-1678
Publication Date(Web):2016/12/12
DOI:10.1039/C6TA09239J
A valid pathway has been exploited to create a B,N co-doped carbon shell on the surface of TiO2 nanoparticles (TiO2@CNB) as a support of Pt nanoparticles. The shell thickness of TiO2@CNB can be easily controlled by pyrolysis of TiO2@polymer networks. The as-prepared Pt/TiO2@CNB catalyst with a thicker CNB layer of 5.0 ± 0.5 nm shows improved performance for the oxygen reduction reaction (ORR) with high onset (0.65 V) and half-wave potentials (0.56 V), which are significantly higher than those of commercial Pt/C (20 wt%) catalysts. For the methanol oxidation reaction (MOR), the Pt/TiO2@CNB catalyst with a moderate CNB layer of 3.3 ± 0.3 nm thickness demonstrates the highest activity and stability compared with that with a CNB thickness of 2.1 ± 0.3, or 5.0 ± 0.5 nm, even Pt/C. Our findings indicate that the synergy between Pt nanoparticles and the B,N co-doped carbon shell, as well as the shell thickness plays a key role in improving the electrochemical performances of the Pt/TiO2@CNB composite materials.
Co-reporter:Conghui Yuan, Ying Chang, Jie Mao, Shirong Yu, Weiang Luo, Yiting Xu, S. Thayumanavan and Lizong Dai
Journal of Materials Chemistry A 2015 - vol. 3(Issue 14) pp:NaN2866-2866
Publication Date(Web):2015/02/18
DOI:10.1039/C4TB01880J
Intermolecular B–N coordination has been recognized as a promising driving force for molecular self-organization. However, direct utilization of this intermolecular interaction as a building bridge for the supramolecular self-assembly of chemical functionalities to form nano-sized architectures remains a daunting challenge. Here, we outline a multiple intermolecular B–N coordination based supramolecular system, where small boronate molecules can be brought together in solution to form nanoparticles with controllable sizes and morphologies. We not only demonstrate the intrinsic switchable fluorescence and the stimuli-responsive capabilities of designed boronate molecules, but also show that the stabilized or surface functionalized nanoparticles are degradable in response to pH and D-glucose and able to retain the fluorescence features of the boronate molecules. Additionally, the degraded nanoparticles can repair themselves through the reformation of B–N coordination.
Co-reporter:Nina Jiang, Yiting Xu, Ning He, Jiangfeng Chen, Yuanming Deng, Conghui Yuan, Guobin Han and Lizong Dai
Journal of Materials Chemistry A 2010 - vol. 20(Issue 48) pp:NaN10855-10855
Publication Date(Web):2010/10/12
DOI:10.1039/C0JM01705A
Walnut-like structures made up of a polyaniline (PANI) nanofiber network and polystyrene (PS) microspheres are successfully fabricated by a novel approach, “competitive adsorption–restricted polymerization”. In the reaction system, PS microspheres are simultaneously encapsulated by cationic surfactant and aniline hydrochloride. Just this cationic surfactant molecule affects the nucleation model and second growth of PANI via electrostatic interactions and steric hindrance, which accounts for the formation of a PANI nanofiber network coating on the PS surface. The size, ordering and amount of PANI nanofibers on the three-dimensional surface can be particularly controlled by altering a variety of synthetic conditions, such as the amount of cationic surfactant, temperature and concentration. A superhydrophobic and conductive surface is obtained by drop-casting a suspension of these walnut-like PS/PANI particles onto a substrate.
Co-reporter:Conghui Yuan;Lina Zhong;Cangjie Yang;Guangjian Chen;Binjie Jiang;Yuanming Deng;Yiting Xu;Weiang Luo;Birong Zeng;Jie Liu
Journal of Materials Chemistry A 2012 - vol. 22(Issue 15) pp:
Publication Date(Web):2012/03/20
DOI:10.1039/C2JM16578C
3D Au nanodendrimers constructed by radially arranged thin nano-sheets show tunable morphology and diameter. The unexpectedly large specific surface area resulting from the novel porous nanostructure makes the 3D Au nanodendrimers exhibit high catalytic activity and long service life.
Co-reporter:Yang Li, Jinyan Lin, Hongjie Wu, Mengmeng Jia, Conghui Yuan, Ying Chang, Zhenqing Hou and Lizong Dai
Journal of Materials Chemistry A 2014 - vol. 2(Issue 38) pp:NaN6548-6548
Publication Date(Web):2014/08/01
DOI:10.1039/C4TB00499J
In the present study we have investigated novel MTX prodrug-targeted and MMC-loaded PLA–lipid–PEG hybrid NPs. These employ a double emulsion solvent evaporation method for the introduction of an anticancer drugs moiety of the MMC–soybean phosphatidylcholine complex or DSPE–PEG–MTX, in which the MTX prodrug can be exploited as a targeting ligand. The prepared drug delivery systems present a spherical shape, a small particle size (219.6 ± 2.1 nm) with narrow particle size distribution, high MMC encapsulation efficiency (90.5 ± 3.0%) and a sustained and pH-controlled MMC release. The advantage of the new drug delivery systems is that the two-anticancer drug moiety can coordinate the early-phase targeting effect with the later-phase anticancer effect. In vivo pharmacokinetics, following intravenous administration of the drug delivery systems, indicates a prolonged systemic circulation time of MMC. More importantly, the drug delivery systems exhibited a significant accumulation of MMC in the nuclei as the site of MMC action, which was indicative of the enhancement of anticancer activity. Such a design of drug delivery systems may open up a new horizon for targeted delivery and sustained and controlled release of MMC.
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![2λ5,4λ5,6λ5-1,3,5,2,4,6-Triazatriphosphorine, 2,4,6-trichloro-2,4,6-tris[1-methyl-1-(6-oxido-6H-dibenz[c,e][1,2]oxaphosphorin-6-yl)ethoxy]-](/data/chemimg/3784200/1882901-95-2.png)
![2λ5,4λ5,6λ5-1,3,5,2,4,6-Triazatriphosphorine, 2,4,6-trichloro-2,4,6-tris[1-methyl-1-(6-oxido-6H-dibenz[c,e][1,2]oxaphosphorin-6-yl)ethoxy]-](/data/chemimg/3784200/1882901-95-2_b.png)
![6H-Dibenz[c,e][1,2]oxaphosphorin-6-amine, N,N'-(methylenedi-4,1-phenylene)bis-, 6,6'-dioxide](/data/chemimg/3785000/1922094-57-2.png)
![6H-Dibenz[c,e][1,2]oxaphosphorin-6-amine, N,N'-(methylenedi-4,1-phenylene)bis-, 6,6'-dioxide](/data/chemimg/3785000/1922094-57-2_b.png)
![Titanium, [1,3,5,7,9,11,14-heptakis(2-methylpropyl)tricyclo[7.3.3.15,11]heptasiloxane-3,7,14-triolato(3-)-κO3,κO7,κO14][2-[[(6-oxido-6H-dibenz[c,e][1,2]oxaphosphorin-6-yl)methyl]amino]ethanolato-κO]-, (T-4)-](/data/chemimg/3785000/1967012-29-8.png)
![Titanium, [1,3,5,7,9,11,14-heptakis(2-methylpropyl)tricyclo[7.3.3.15,11]heptasiloxane-3,7,14-triolato(3-)-κO3,κO7,κO14][2-[[(6-oxido-6H-dibenz[c,e][1,2]oxaphosphorin-6-yl)methyl]amino]ethanolato-κO]-, (T-4)-](/data/chemimg/3785000/1967012-29-8_b.png)
![6H-Dibenz[c,e][1,2]oxaphosphorin-6-amine, N,N'-(sulfonyldi-4,1-phenylene)bis-, 6,6'-dioxide](/data/chemimg/3785000/1970149-99-5.png)
![6H-Dibenz[c,e][1,2]oxaphosphorin-6-amine, N,N'-(sulfonyldi-4,1-phenylene)bis-, 6,6'-dioxide](/data/chemimg/3785000/1970149-99-5_b.png)
![Pentacyclo[9.5.1.13,9.15,15.17,13]octasiloxane-1-propanamine, 3,5,7,9,11,13,15-heptakis(1-methylethyl)-](/data/chemimg/3783200/2109797-11-5.png)
![Pentacyclo[9.5.1.13,9.15,15.17,13]octasiloxane-1-propanamine, 3,5,7,9,11,13,15-heptakis(1-methylethyl)-](/data/chemimg/3783200/2109797-11-5_b.png)
![6H-Dibenz[c,e][1,2]oxaphosphorin, 6-(2-oxiranylmethoxy)-, 6-oxide](/data/chemimg/3784200/2109797-12-6.png)
![6H-Dibenz[c,e][1,2]oxaphosphorin, 6-(2-oxiranylmethoxy)-, 6-oxide](/data/chemimg/3784200/2109797-12-6_b.png)
![3H-Indolium,2-[3-(1,3-dihydro-3,3- dimethyl-1-octadecyl-2H-indol-2-ylidene)- 1-propenyl]-3,3-dimethyl-1-octadecyl-,perchlorate](http://img.cochemist.com/ccimg/41100/41085-99-8.png)
![3H-Indolium,2-[3-(1,3-dihydro-3,3- dimethyl-1-octadecyl-2H-indol-2-ylidene)- 1-propenyl]-3,3-dimethyl-1-octadecyl-,perchlorate](http://img.cochemist.com/ccimg/41100/41085-99-8_b.png)
![2-Propenoic acid, 2-methyl-, 3-[3,5,7,9,11,13,15-heptakis(2-methylpropyl)pentacyclo[9.5.1.13,9.15,15.17,13]octasiloxan-1-yl]propyl ester, homopolymer](/data/chemimg/109700/425409-08-1.png)
![2-Propenoic acid, 2-methyl-, 3-[3,5,7,9,11,13,15-heptakis(2-methylpropyl)pentacyclo[9.5.1.13,9.15,15.17,13]octasiloxan-1-yl]propyl ester, homopolymer](/data/chemimg/109700/425409-08-1_b.png)
