Co-reporter:Kewen Li, Chao Zhou, Shunli Liu, Fang Yao, Guodong Fu, Liqun Xu
Reactive and Functional Polymers 2017 Volume 117(Volume 117) pp:
Publication Date(Web):1 August 2017
DOI:10.1016/j.reactfunctpolym.2017.06.010
Hydrogels have been considered as promising materials in tissue engineering and biomedical areas. However, the weak and brittle nature of common synthetic hydrogels largely hinders their potential applications. Therefore, it is challenging to fabricate tough hydrogels for biomedical applications. In this manuscript, well-defined and thermo-responsive polyurethane-poly(ethylene glycol) (PU-PEG) hydrogels were prepared via thermally-induced copper-catalyzed 1,3-dipolar azide-alkyne cycloaddition (CuAAC) using azido-pendent PU-PEG and dialkynyl PEG as the gel precursors. The physical properties of the as-formed hydrogels were investigated by swelling ratios and mechanical tests. The PU-PEG hydrogels not only possess thermo-responsive and excellent mechanical properties, but also exhibit good biocompatibility.
Co-reporter:Shunli Liu, Fang Yao, Olayinka Oderinde, Zhihong Zhang, Guodong Fu
Carbohydrate Polymers 2017 Volume 174(Volume 174) pp:
Publication Date(Web):15 October 2017
DOI:10.1016/j.carbpol.2017.06.044
•A facile three-dimensional xanthan gum/graphene oxide hybrid aerogel was fabricated by ice crystal templating.•A network composed of co-aligned pore channels was obtained at a low freezing temperature (−40 °C).•The as-prepared hybrid aerogels exhibited stability and excellent adsorption capacity for organic dyes and heavy metal ions.Three-dimensional xanthan gum (XG)/graphene oxide (GO) hybrid aerogels were fabricated by ice crystal templating without using chemical modifiers. The hybrid aerogels were prepared by the stirring of xanthan gum-graphene oxide hybrid solution, followed by freezing at low temperature and finally by freeze-drying. The whole preparation could be completed within 12 h without producing any contamination and thus considered a fast, simple, economical, and green method for aerogel fabrication. XG/GO hybrid aerogels possessed different hierarchical pore structures because of various freezing temperatures. A network composed of co-aligned pore channels was obtained at a freezing temperature of −40 °C. The as-prepared hybrid aerogels exhibited stability and excellent adsorption capacity for organic dyes and heavy metal ions. Therefore, these aerogels could be used as efficient adsorbents in water purification. This study provided a basis for the cost-effective and large-scale commercial production of high-performance graphene oxide-based aerogels for water purification.
Co-reporter:Zhiqiang Sun, Shunli Liu, Kewen Li, Linhua Tan, Lian Cen and Guodong Fu
Soft Matter 2016 vol. 12(Issue 7) pp:2192-2199
Publication Date(Web):24 Dec 2015
DOI:10.1039/C5SM02129D
In the present study, novel hydrogels with extremely high strength, reversible photoresponsive and excellent biocompatible properties were prepared. The functional hydrogels were synthesized from a well-defined poly (ethylene glycol) polymer with spiropyran groups at a given position (PEG-SP) via a Cu(I)-catalyst Azide-Alkyne Cycloaddition (CuAAC) reaction. The molecular structures of the sequential intermediates for PEG-SP hydrogel preparation were verified by 1HNMR and FT-IR. The mechanical property, swelling ratio, compression strength, surface hydrophilicity, and biocompatibility of the resulting hydrogel were characterized. Since spiropyran is pivotal to the switch in hydrophilicity on the hydrogel surface, the swelling ratio of PEG-SP hydrogel under Vis irradiation has a major decrease (155%). Before and after UV light irradiation, the contact angle of the hydrogel has a change of 13.8°. The photoresponsive property of this hydrogel was thus demonstrated, and such a property was also shown to be reversible. The well-defined PEG-SP hydrogel can also sustain a compressive stress of 49.8 MPa without any macro- or micro-damage, indicating its outstanding mechanical performance. Furthermore, it possessed excellent biocompatibility as demonstrated by its performance in an in vivo porcine subcutaneous implantation environment. No inflammation was observed and it got along well with the adjacent tissue. The above features indicate that PEG-SP hydrogels are promising as an implantable matrix for potential applications in biomaterial.
Co-reporter:Shunli Liu, Jun Ling, Kewen Li, Fang Yao, Olayinka Oderinde, Zhihong Zhang and Guodong Fu
RSC Advances 2016 vol. 6(Issue 68) pp:63171-63177
Publication Date(Web):28 Jun 2016
DOI:10.1039/C6RA11729E
Inspired by the heterogeneous architectures of biological composites, mimicking the hierarchical structure of nacre is a powerful strategy to construct high-performance materials. This paper presents a lightweight and nacre-like hierarchical paper which was fabricated via lanthanide ion coordination. Sodium alginate (SA) biopolymers and lanthanide ions (Nd3+, Gd3+, Ce3+ and Yb3+) were used as ideal building blocks and connection points, respectively. SA biopolymers and lanthanide ions rapidly self-assembled into an aligned hydrogel. The synthesized hydrogel was subsequently dried to form layered alginate-based papers. The formation mechanism of the layered paper was investigated and demonstrated that lanthanide ion coordination can produce the hierarchical structure. The as-prepared layered SA–Nd(III) nanopaper exhibited a high strength of 124.2 ± 5.2 MPa, toughness of 8.2 ± 0.4 MJ m−3, and Young's modulus of 5.2 ± 0.2 GPa, as well as excellent resistance to solvents. Owing to their outstanding mechanical properties and easy and fast fabrication, the layered SA–Nd(III) papers demonstrated a potential application in the fields of biomaterials. This new strategy based on lanthanide ion coordination, can also be used to construct integrated, high-performance, and biopolymer materials.
Co-reporter:JingJing Ding, Chao Zhou, KeWen Li, AoKai Zhang, Fang Yao, LiQun Xu and GuoDong Fu
RSC Advances 2016 vol. 6(Issue 33) pp:27871-27878
Publication Date(Web):03 Mar 2016
DOI:10.1039/C6RA01581F
In this work, well-defined PEG-based fibrous hydrogels (FH's) were successfully prepared via electrospinning and in situ copper(I)-catalyzed azide–alkyne cycloaddition (CuAAC) reaction. Initially, the linear functional PEG derivatives with pendant alkynyl groups (PEGn(CCH))m and with azido moieties (PEGn(N3))m were synthesized via epoxide-amine chain-extension reaction between poly(ethylene glycol) diglycidyl ether (PEGDGE) and propargylamine/1-azido-3-aminopropane. Subsequently, the PEG-based FHs were fabricated from the blends of poly(ethylene oxide) (PEO) and the functional PEG derivatives via electrospinning and in situ CuAAC reaction using the encapsulated copper nanoparticles as the catalyst. The blends of PEO and the functional PEG derivatives were also utilized to prepare the microscopic hydrogels (MH's). The properties of the FH's and MH's were investigated by scanning electron microscopy (SEM) observation, swelling ratios, differential scanning calorimetry (DSC) and in vitro degradation. The copper nanoparticles-encapsulated FH's and MH's were further used to catalyze the CuAAC reaction in a small molecule model. The reusability of the FH's for the CuAAC reaction was also studied.
Co-reporter:Ao-kai Zhang;Jun Ling;Kewen Li;Tasuku Nakajima;Takayuki Nonoyama;Takayuki Kurokawa;Jian Ping Gong
Journal of Polymer Science Part B: Polymer Physics 2016 Volume 54( Issue 13) pp:1227-1236
Publication Date(Web):
DOI:10.1002/polb.24028
ABSTRACT
In this study, controlled amount of dangling ends is introduced to the two series of poly(ethylene glycol)-based hydrogel networks with three and four crosslinking functionality by using click chemistry. The structure of the gels with regulated defect percentage is confirmed by comparing the results of low-field NMR characterization and Monte Carlo simulation. The mechanical properties of these gels were characterized by tensile stress–strain behaviors of the gels, and the results are analyzed by Gent model and Mooney–Rivlin model. The shear modulus of the swollen gels is found to be dependent on the functionality of the network, and decreases with the defect percentage. Furthermore, the value of shear modulus well obeys the Phantom model for all the gels with varied percentage of the defects. The maximum extension ratio, obtained from the fitting of Gent model, is also found to be dependent on the functionality of the network, and does not change with the defect percentage, except at very high defect percentage. The value of the maximum extension ratio is between that predicted from Phantom model and the Affine model. This indicates that at the large deformation, the fluctuation of the crosslinking points is suppressed for some extend but still exists. Polymer volume fractions at various defect percentages obtained from prediction of Flory–Rehner model are found to be in well agreement with the swelling experiment. All these results indicate that click chemistry is a powerful method to regulate the network structure and mechanical properties of the gels. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016, 54, 1227–1236
Co-reporter:Chao Zhou;Vinh X. Truong;Yue Qu;Trevor Lithgow;Guodong Fu;John S. Forsythe
Journal of Polymer Science Part A: Polymer Chemistry 2016 Volume 54( Issue 5) pp:656-667
Publication Date(Web):
DOI:10.1002/pola.27886
ABSTRACT
Antibacterial hydrogels containing quaternary ammonium (QA) groups were prepared via a facile thiol-ene “click” reaction using multifunctional poly(ethylene glycol) (PEG). The multifunctional PEG polymers were prepared by an epoxy-amine ring opening reaction. The chemical and physical properties of the hydrogels could be tuned with different crosslinking structures and crosslinking densities. The antibacterial hydrogel structures prepared from PEG Pendant QA were less well-defined than those from PEG Chain-End QA. Furthermore, functionalization of the PEG-type hydrogels with QA groups produced strong antibacterial abilities against Staphylococcus aureus, and therefore has the potential to be used as an anti-infective material for biomedical devices. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 656–667
Co-reporter:Meng-jiao Dong;Shun-li Liu;Lin-hua Tan;Lian Cen 岑莲
Chinese Journal of Polymer Science 2016 Volume 34( Issue 5) pp:637-648
Publication Date(Web):2016 April
DOI:10.1007/s10118-016-1783-7
The aim of the present work was to prepare a well-defined hydrogel of chemically cross-linked and organ-metallic complexed interpenetrating PEG networks. The hydrogel was synthesized via the reaction of copper(I)- catalyzed 1,3-dipolar azide-alkyne cycloaddition (CuAAC) with poly(ethylene glycol)-dopamine (PEG-DA) (“Click Chemistry”) followed by complexation with Fe3+ ions to crosslink the polymeric network. The chemical composition and morphology of the resulting hydrogels were characterized by Fourier transform infrared spectroscopy (FTIR), 1H-NMR and scanning electron microscopy (SEM). Swelling ratio, mechanical strength, conductivity, and degradation behaviors of the hydrogels were also studied. The effect of the polymer chain length on properties of hydrogels was explored. The compressive strength of hydrogels could reach as high as 13.1 MPa with a conductivity of 2.2 × 10-5 S·cm-1. The hydrogels also exhibited excellent thermal stability even at a temperature of 300 °C, whereas degradation of the hydrogel after 7 weeks was observed under a physiological condition. In addition, the hydrogel exhibited a good biocompatibility based on its in vivo performance through an in vivo subcutaneous implantation model. No inflammation and no obvious abnormality of the surrounding tissue were observed when the hydrogel was subcutaneously implanted for 2 weeks. This work is a step towards creating a new pathway to synthesize hydrogels of interpenetrating networks which could be of important applications in the future research.
Co-reporter:Yang Li, Chao Zhou, Liqun Xu, Fang Yao, Lian Cen and Guo Dong Fu
RSC Advances 2015 vol. 5(Issue 24) pp:18242-18251
Publication Date(Web):05 Feb 2015
DOI:10.1039/C4RA11946K
A novel strategy to synthesize stimuli-responsive metal-coordinated polymeric gels (MCPGs) via one-pot CuAAC and non-covalent metal coordination chemistry was demonstrated. 4′-(4-Prop-2-ynyloxyphenyl)-2,2′:6′,2′′-terpyridine (Terpy-φ-CH2CCH) and α,ω-diazido/hydroxyl PEG (PEG45(N3)2) were used as precursors to yield linear terpyridine-terminated PEG derivatives with 1,2,3-triazole rings and terpyridine ligands in their main chains to serve as ligands for chelating a range of transition and/or lanthanide metal ions. It was found that the bridging metal complexes could not only act as branching or crosslinking sites within the three-dimensional polymer networks but could also bestow special properties to the final gels, such as stimuli-responsive and thixotropic features, thereby allowing facile and efficient design and synthesis of promising intelligent materials.
Co-reporter:Li Qun Xu;Jiu Cun Chen;Shan Shan Qian;Ao Kai Zhang;Guo Dong Fu;Chang Ming Li;En-Tang Kang
Macromolecular Chemistry and Physics 2015 Volume 216( Issue 4) pp:417-426
Publication Date(Web):
DOI:10.1002/macp.201400477
Co-reporter:Ao-kai Zhang;Jun Ling 凌君;Yu-wei Sun
Chinese Journal of Polymer Science 2015 Volume 33( Issue 5) pp:721-731
Publication Date(Web):2015 May
DOI:10.1007/s10118-015-1620-4
Three-dimensional (3-D) coarse-grained Monte Carlo algorithms were used to simulate the conformations of swollen hydrogels formed by copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC). The simulation consists of three successive steps including diffusion, cross-linking and relaxation. The cross-linking of multifunctional reaction sites is simulated instantly followed by fast crosslinking. In order to explore the validity of this approach pristine poly(ethylene glycol) (PEG) hydrogels with tri- and tetra-functional reaction sites (G3 and G4 respectively) were prepared and characterized. The data from the simulations were found to be in good agreement with experimental results such as PEG lengths between crosslinks, pore volume and pore radius distribution, indicating the validity of the modeling algorithm. The calculated PEG lengths in G3 and G4 networks are close (≈ 4.6 nm). The 3-D visual topological structure of the hydrogel network suggests that the “ideal” hydrogel is far from cubic, diamond or any well defined structures of regular repeating cells.
Co-reporter:Li Qun Xu, Beatrice Swee Min Yap, Rong Wang, Koon-Gee Neoh, En-Tang Kang, and Guo Dong Fu
Industrial & Engineering Chemistry Research 2014 Volume 53(Issue 8) pp:3116-3124
Publication Date(Web):2017-2-22
DOI:10.1021/ie403840p
Narrowly dispersed raspberry-like SiO2@poly(dopamine acrylamide-co-methacrylic acid-co-ethylene glycol dimethacrylate)/Ag (or SiO2@PDA/Ag) composite nanospheres were synthesized via a combination of sol–gel reaction, distillation-precipitation polymerization, reactive ester-amine reaction, and electroless metallization. In this approach, SiO2@poly(pentafluorophenyl acrylate-co-methacrylic acid-co-ethylene glycol dimethacrylate) (or SiO2@PPFA) core–shell nanospheres were first prepared by distillation-precipitation polymerization, using the SiO2-3-(trimethoxysilyl)propyl methacrylate (SiO2-MPS) nanospheres from sol–gel reaction as seeds. The reactive pentafluorophenyl (PFP) ester moieties on SiO2@PPFA nanospheres can readily react with dopamine hydrochloride to form amide linkages with no side reaction under a mild condition. The catecholamine moieties in the resulting SiO2@PDA nanospheres were utilized for simultaneous reduction of Ag+ ions and coordinative binding of the metal nanoparticles. The SiO2-MPS, SiO2@PPFA, and SiO2@PDA nanospheres as well as the raspberry-like SiO2@PDA/Ag composite nanospheres were characterized by field-emission transmission electron microscopy (FETEM), thermogravimetric analysis (TGA), dynamic light scattering (DLS), X-ray photoelectron spectroscopy (XPS), and FT-IR spectroscopy. Furthermore, the as-synthesized SiO2@PDA/Ag composite nanospheres were explored for the catalytic reduction of p-nitrophenol and degradation of rhodamine 6G (R6G) dye.
Co-reporter:Chao Zhou, Linhong Deng, Fang Yao, Liqun Xu, Jian Zhou, and Guo Dong Fu
Industrial & Engineering Chemistry Research 2014 Volume 53(Issue 49) pp:19239-19248
Publication Date(Web):November 20, 2014
DOI:10.1021/ie503649t
Well-defined amphiphilic polymer conetworks with precisely controlled number and position of cross-links were prepared by copper-catalyzed azide–alkyne cycloaddition (CuAAC) using linear polystyrene (PS) and poly(ethylene glycol) (PEG) as the building blocks. In this approach, linear polystyrene containing a specific number of bromo groups at a predetermined position of polymer chains was synthesized by multistep reversible addition–fragmentation chain transfer polymerization and chain extension using styrene and N-bromopropyl maleimide (PBMI) as the monomers. Subsequently, the bromo groups were transformed into the azido moieties via nucleophilic substitution. The well-defined linear multialkynyl PEG was prepared from PEG diglycidyl ether and propargylamine via epoxy-amine chain extension. The as-prepared PS–PEG amphiphilic polymer conetworks showed unique hydrophilic and hydrophobic phase separation with a variable swelling capacity and rheological behavior in both polar and nonpolar solvents and exhibited excellent mechanical properties with increased cross-linking density.
Co-reporter:Chao Zhou, Shan-shan Qian, Xia-jun Li, Fang Yao, John S. Forsythe and Guo-dong Fu
RSC Advances 2014 vol. 4(Issue 97) pp:54631-54640
Publication Date(Web):08 Oct 2014
DOI:10.1039/C4RA09438G
Multi-responsive poly(acrylic acid)–poly(ethylene glycol) (PAA–PEG) hydrogels with well-defined crosslinking structures were synthesized using atom transfer radical polymerization (ATRP) and copper-catalyzed 1,3-dipolar azide-alkyne cycloaddition (CuAAC) techniques. The well-defined PAA–PEG hydrogels with different degrees of crosslinking were produced from controlling the molecular weight of the PAA and PEG chains. The prepared multi-responsive hydrogels exhibit regular physical and mechanical properties by adjusting the pH and Ca2+ ion secondary crosslinking. With increasing pH, the swelling ratio of the well-defined multi-responsive PAA–PEG hydrogels increased remarkably. Furthermore, the well-defined PAA–PEG hydrogels with Ca2+ secondary crosslinking possessed a significantly higher crosslinking density as reflected by the lower swelling ratio, higher storage modulus, higher electrical conductivity and thermal stability. An in vitro cell viability assay also indicated that well-defined multi-responsive PAA–PEG hydrogels are biocompatible and have potential for implantable biomaterials.
Co-reporter:ShanShan Qian, Chao Zhou, LiQun Xu, Fang Yao, Lian Cen and GuoDong Fu
RSC Advances 2014 vol. 4(Issue 48) pp:25241-25250
Publication Date(Web):29 May 2014
DOI:10.1039/C4RA01870B
In this work, PEG-based single-chain hydrogels with extremely high strength were successfully prepared via precise design and control over the molecular topology of the polymeric network. Initially, well-defined PEG macromolecules with uniformly dispersed pendant alkynyl groups (PEGn(CCH))m on their main chains were synthesized via amine-epoxy chain extension reaction of α,ω-diepoxy PEG and propargylamine. The subsequent copper(I)-catalyzed azide–alkyne 1,3-dipolar cycloaddition (CuAAC) of (PEGn(CCH))m and α,ω-diazido PEGn (PEGn(N3)2) gave rise to tough PEG-based hydrogels (Gel-PEGn(N3)2-(PEGn(CCH))m). The lattice size of the Gel-PEGn(N3)2-(PEGn(CCH))m networks can be tailored by varying chain lengths of PEG repeating segments in (PEGn(CCH))m and PEGn(N3)2. Different from traditional PEG hydrogels prepared by CuAAC, such as hydrogels from tetrakis(2-propynyloxymethyl)methane and PEGn(N3)2, the current novel hydrogels possess not only a high mechanical strength up to 62.5 MPa, but are also biodegradable favored by the presence of triethylamine groups in the (PEGn(CCH))m macromolecules. Furthermore, excellent biocompatibility of the Gel-PEGn(N3)2-(PEGn(CCH))m was demonstrated according to the in vitro cytotoxicity assay. Hence, it can be ascertained that Gel-PEGn(N3)2-(PEGn(CCH))m has promising potential for artificial medical devices or scaffolding materials for regenerative medicine.
Co-reporter:Chao Zhou, Shanshan Qian, Aokai Zhang, Liqun Xu, Jian Zhu, Zhengping Cheng, En-Tang Kang, Fang Yao and Guo Dong Fu
RSC Advances 2014 vol. 4(Issue 16) pp:8144-8156
Publication Date(Web):14 Jan 2014
DOI:10.1039/C3RA47939K
Linear polystyrene (PS) with well-defined molecular structure and accurate numbers of bromo groups on both ends were synthesized via multiple-step alternative RAFT polymerization of N-bromopropyl maleimide and β-pinene monomers. The bromo end groups were transformed into the azido moieties via nucleophilic substitution. The reaction of as-synthesized linear PS having a named number of azide groups on ends ((N3)x–PS–(N3)x) with mono- and dialkynyl-terminated PEG (dA-PEG) via copper(I)-catalyzed azide–alkyne cycloaddition (CuAAC) leads to the formation of the well-defined PS–PEG amphiphilic copolymers and polymeric co-networks (APCNs). The as-prepared APCNs exhibit unique ordered separated hydrophilic and hydrophobic phases, and a variable swelling capacity both in polar and non-polar solvents.
Co-reporter:Fang Yao;Guan-Cang Yan;Li-Qun Xu;Li-Hong Yin;Yue-Pu Pu;En-Tang Kang
Polymer International 2014 Volume 63( Issue 2) pp:237-243
Publication Date(Web):
DOI:10.1002/pi.4491
Abstract
Well-defined hairy and crosslinked fluorescent nanoparticles with diameters in the range 70–220 nm were obtained from simultaneous copper-catalyzed alkyne–azide cycloaddition (CuAAC) and atom transfer radical emulsion polymerization (ATREP) of a mixture of styrene, divinylbenzene, 4-vinylbenzylazide and 7-propinyloxycoumarin (Cr), using bromide-terminated poly(ethylene glycol) (PEG) as macroinitiator, Tween-20 as emulsifier, copper(I) bromide as catalyst and pentamethyldiethylenetriamine as ligand. The generation of biocompatible PEG brushes and the introduction of fluorescent functionalities as well as crosslinking of nanoparticles were realized in one step. In order to verify that functionalization and propagation of polymer chains could be realized in a controlled manner by one-pot simultaneous ATREP and CuAAC, linear block copolymers of PEG and polystyrene (PS) with partially clicked pendent Cr groups (PEG-b-(PS-c-Cr)) were synthesized. All prepared PEG-b-(PS-c-Cr) copolymers had a controlled molecular weight and defined molecular structure. The hairy fluorescent nanoparticles exhibit a low cytotoxicity and could find applications in cell labeling. © 2013 Society of Chemical Industry
Co-reporter:Li Qun Xu, Koon-Gee Neoh, En-Tang Kang and Guo Dong Fu
Journal of Materials Chemistry A 2013 vol. 1(Issue 7) pp:2526-2532
Publication Date(Web):08 Jan 2013
DOI:10.1039/C2TA01072K
Mercury pollution is a widespread problem. In this work, a solid-state sensor based on rhodamine derivative-modified cellulose filter papers for detection of Hg2+ ions in aqueous media is demonstrated. A three-step approach, involving the introduction of atom transfer radical polymerization (ATRP) initiating sites, surface-initiated ATRP (SI-ATRP) of pentafluorophenyl methacrylate, and post-functionalization of the reactive surface with amino-containing spirolactam rhodamine derivatives in ester–amine reaction, was developed for the covalent immobilization of mercury-responsive probes on the cellulose filter paper. This solid-state sensor exhibits highly selective recognition of Hg2+ ions in a Tris–HNO3 buffer solution (pH = 7.24) over various environmentally relevant metal ions with remarkably enhanced fluorescent emission intensity and distinct color change from colorless to pink. The response of a rhodamine derivative-modified cellulose filter paper to Hg2+ ions is fast (<2 min). The positive fluorescence response and color change of this functionalized filter paper thus provide a disposable solid-state sensor for fluorescent and “naked-eye” detection of Hg2+ ions.
Co-reporter:Yang Yuan, Ao-Kai Zhang, Jun Ling, Li-Hong Yin, Yue Chen and Guo-Dong Fu
Soft Matter 2013 vol. 9(Issue 27) pp:6309-6318
Publication Date(Web):04 Jun 2013
DOI:10.1039/C3SM27853K
A series of amphiphilic conetworks (APCNs) with well-defined molecular structures were prepared via a copper-catalyzed 1,3-dipolar azide–alkyne cycloaddition (CuAAC) of tetrakis(2-propynyloxymethyl)methane (TMOP), diazide end-functionalized triblock copolymers of poly(ε-caprolactone) with poly(ethylene glycol) (N3-PCL-PEG-PCL-N3). The so-prepared APCNs exhibit unique properties of ordered nanophase separation of hydrophilic (HI) and hydrophobic (HO) phases, and a variable swelling capacity both in water and organic solvent. The morphology, surface properties and thermal behavior of the APCNs were investigated by scanning electron microscopy (SEM), water contact angle (WCA), and differential scanning calorimetry (DSC), respectively. The physical properties of APCNs depended on the ratio of HI–HO, which can be regulated via precise synthesis of N3-PCL-PEG-PCL-N3. The analysis of an in vitro cell viability assay suggests that the APCNs have excellent biocompatibility. The prepared APCNs are excellent carriers for controlled drug release. The hydrophilic choline theophyllinate and hydrophobic 5-fluorouracil (5-FU) were loaded into the APCNs simultaneously as model drugs to study the release from APCNs. The well-controlled drug release is attributable to the well-defined molecular structure and tunable HI/HO composition of the APCNs.
Co-reporter:Li Qun Xu, Jiu Cun Chen, Rong Wang, Koon-Gee Neoh, En-Tang Kang and Guo Dong Fu
RSC Advances 2013 vol. 3(Issue 47) pp:25204-25214
Publication Date(Web):18 Oct 2013
DOI:10.1039/C3RA42782J
Poly(dopamine acrylamide)-grafted poly(vinylidene fluoride) (PVDF-g-PDA) microfiltration (MF) membranes were fabricated via (i) thermally-induced radical graft copolymerization of pentafluorophenyl acrylate from ozone-pretreated PVDF, (ii) reactive ester–amine reaction with dopamine hydrochloride, and (iii) membrane casting via phase inversion. The resulting catechol-containing PVDF-g-PDA MF membranes can be further functionalized via spontaneous reduction and chelating of Ag and Au nanoparticles on the surface, and via grafting of thiol-terminated poly(ethylene glycol) (PEG-SH), amino-terminated poly(N-isopropylacrylamide) (PNIPAM-NH2) or amino-terminated hyperbranched polyglycerol (HPG-NH2) in Michael addition or Schiff base reactions. The as-synthesized PVDF-g-PDA/Ag nanoparticles composite MF membrane was explored for its antibacterial efficacy against Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus). The resulting PVDF-g-PDA/Au nanoparticles composite MF membrane was investigated as the catalytic support for the reduction of 4-hydroxynitrobenzene. The obtained PVDF-g-PDA/PNIPAM, PVDF-g-PDA/PEG and PVDF-g-PDA/HPG MF membranes exhibit thermo-responsive, biocompatible and anti-fouling properties, respectively.
Co-reporter:Li Qun Xu, Yon Kiat Yee, Koon-Gee Neoh, En-Tang Kang, Guo Dong Fu
Polymer 2013 Volume 54(Issue 9) pp:2264-2271
Publication Date(Web):19 April 2013
DOI:10.1016/j.polymer.2013.02.043
β-Cyclodextrin (CD)-functionalized (grafted) reduced graphene oxide (RGO-g-CD) nanosheets were prepared via solution-based synthesis in one-pot, involving the simultaneous solvothermal reduction of graphene oxide (GO) and nitrene addition of azido-labeled CD to RGO. Being water soluble, the grafted CD imparted good dispersibility and stability to the RGO-g-CD nanosheets in water. The RGO-g-CD nanosheets were further functionalized with poly(N-isopropylacrylamide-co-vinylferrocene(II)) (PNIPAM-Fc) and ferrocene-modified hyperbranched polyglycerol (HPG-Fc) via host-guest inclusion complexation of CD and ferrocene (Fc) moieties to form RGO-g-CD/Fc-PNIPAM and RGO-g-CD/Fc-HPG nanohybrids, respectively. Both RGO-g-CD/Fc-PNIPAM and RGO-g-CD/Fc-HPG nanohybrids were dispersible and stable in a wider range of solvents than the RGO-g-CD precursor nanosheets. Due to the thermoresponsive behavior of the attached PNIPAM moieties, the RGO-g-CD/Fc-PNIPAM exhibited reversible dispersibility in aqueous solution at a lower critical solution temperature (LCST) of 28 °C and thus could potentially be developed into thermoresponsive nanodevices. The RGO-g-CD/Fc-HPG nanohybrids exhibited low cytotoxicity towards 3T3 fibroblasts in 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) cell viability assay.
Co-reporter:Li Qun Xu, Hua Jiang, Koon-Gee Neoh, En-Tang Kang and Guo Dong Fu
Polymer Chemistry 2012 vol. 3(Issue 4) pp:920-927
Publication Date(Web):30 Jan 2012
DOI:10.1039/C2PY00552B
Poly(dopamine acrylamide)-co-poly(propargyl acrylamide) (PDA-co-PPA) copolymers, containing alkyne- and catechol-functionalities, were prepared from reactive poly(pentafluorophenyl acrylate) (PPFA) via functionalization of the pentafluorophenyl-activated ester groups with dopamine hydrochloride and propargylamine. The bifunctional PDA-co-PPA copolymers were then coupled to the titanium (Ti) surface via coordination interaction of the catechol moieties, yielding a functionalizable Ti platform containing ‘clickable’ alkyne groups on the surface for the copper-catalyzed azide-alkyne 1,3-dipolar cycloaddition (CuAAC) of azide-labeled fluorescein, rhodamine, β-cyclodextrin, poly(ethylene glycol) (PEG), mannose and biotin. The functionalized Ti surfaces from the CuAAC reactions were characterized by fluorescence microscopy (for the rhodamine- and fluorescein-functionalized Ti surfaces), non-specific protein adsorption (for the PEG-grafted Ti surface), specific protein adsorption (for the mannose- and biotin-functionalized Ti surfaces) and host–guest interaction with antibiotics (for the β-cyclodextrin-functionalized Ti surface).
Co-reporter:Guo-Dong Fu;Hua Jiang;Fang Yao;Li-Qun Xu;Jun Ling;En-Tang Kang
Macromolecular Rapid Communications 2012 Volume 33( Issue 18) pp:1523-1527
Publication Date(Web):
DOI:10.1002/marc.201200337
Abstract
Here, we are the first to report a novel approach to preparing well-defined poly(ethylene glycol) (PEG) fluorescent nanogels, with well-defined molecular structures and desired functionalities via reverse (mini)emulsion copper(I)-catalyzed azide-alkyne cycloaddition (REM-CuAAC). Nanogels with hydroxyl groups and Ga-porphyrin complex (Ga-porphyrin-OH nanogels), as well as with Ga-porphyrin complex and folate functional groups (Ga-porphyrin-FA), are successfully prepared. Nanogels of 30 and 120 nm in diameter are obtained and they exhibit an emission maxima within the wavelength range 700–800 nm. The nanogels could find uses in near infrared (NIR) imaging attributable to their fluorescence and their functionality for cell affinity.
Co-reporter:Guo-Dong Fu;Hua Jiang;Fang Yao;Li-Qun Xu;Jun Ling;En-Tang Kang
Macromolecular Rapid Communications 2012 Volume 33( Issue 18) pp:
Publication Date(Web):
DOI:10.1002/marc.201290063
Co-reporter:Fang Yao;Li-Qun Xu;Bao-Ping Lin
Polymer International 2012 Volume 61( Issue 5) pp:749-759
Publication Date(Web):
DOI:10.1002/pi.4134
Abstract
Dendrimer-like polystyrenes (PSs) containing azobenzene moieties/core were prepared by one-pot copper(I)-catalyzed azide–alkyne cycloaddition (CuAAC) and atom transfer radical polymerization (ATRP) in the presence of PS with terminal azide groups, styrene monomers, 2,4-dibromoisobutyrate-4′-propynyloxyazobenzene, copper(I) bromide and ligand. The successful preparation of the dendrimer-like PSs was confirmed using gel permeation chromatography and 1H NMR and Fourier transform infrared spectroscopy. The dendrimer-like PSs prepared from one-pot CuAAC and ATRP exhibit a well-defined and controlled molecular structure in both whole macromolecules and the branches, which is attributed to the controlled character of ATRP and the quantitative yield of click chemistry. The dendrimer-like PSs prepared also exhibit good photo-isomerization properties due to the incorporation of azobenzene units within the dendrimers. Copyright © 2012 Society of Chemical Industry
Co-reporter:Hong Yang;Qi Zhang;Baoping Lin;Guodong Fu;Xueqin Zhang ;Lingxiang Guo
Journal of Polymer Science Part A: Polymer Chemistry 2012 Volume 50( Issue 20) pp:4182-4190
Publication Date(Web):
DOI:10.1002/pola.26244
Abstract
This manuscript describes a straightforward method to prepare stimuli-responsive fibers by the combined technology of electrospinning and two facile thiol-ene click chemistry processes: photo-initialized thiol-ene radical addition and thiol-Michael nucleophilic addition. By controlling the molar ratio of poly((3-mercaptopropyl)methylsiloxane) (PMMS) and the cross-linker, triallyl cyanurate, PMMS-based fibers can be partially photo-crosslinked via UV illumination during electrospinning, to grant them the solvent-resistant property, meanwhile leaving unreacted free mercapto groups on the surfaces, which could be further functionalized with stimuli-responsive polymer brushes. To demonstrate the feasibility of this approach, a facile thiol-Michael addition protocol between PMMS fibers with free thiol groups on the surfaces and maleimide-terminated PNIPAM has been developed, which allows for the preparation of polysiloxane fibers with thermo-responsive PNIPAM brushes on the surfaces. PMMS-g-PNIPAM fibers show thermo-sensitive behavior to the environment, having a hydrophilic surface at 20°C (water contact angle ∼28°) and a hydrophobic surface at 45°C (water contact angle ∼132°). © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012.
Co-reporter:Guo-Dong Fu, Guo Liang Li, K.G. Neoh, E.T. Kang
Progress in Polymer Science 2011 Volume 36(Issue 1) pp:127-167
Publication Date(Web):January 2011
DOI:10.1016/j.progpolymsci.2010.07.011
The development of reliable synthetic routes to polymeric nanostructures of well-defined composition, morphology and function is of scientific importance and technological interest. The generation of functional hollow polymeric nanostructures, hollow nanospheres and nanotubes in particular, can be achieved through direct and template-directed synthesis, core–shell precursors, and self-assembly of copolymers and polymer conjugates, as well as from dendrimers. The ability to prepare precursor macromolecules of well-defined structure and architecture has been substantially enhanced by recent advances in controlled radical polymerizations. The application and potential application of the hollow polymeric nanospheres and nanotubes as nanoreactors, and in diagnostics, encapsulation, controlled release, and other stimuli-responsive systems are also described.
Co-reporter:Rong Fu and Guo-Dong Fu
Polymer Chemistry 2011 vol. 2(Issue 3) pp:465-475
Publication Date(Web):20 Sep 2010
DOI:10.1039/C0PY00174K
This review highlights recent research on the preparation of functional polymeric nanomaterials (nanoparticles, microcapsules, nanofibers, carbon nanotubes) by combined ‘click chemistry’ and controlled radical polymerization (CRP) techniques. In particular, it focuses primarily on combined atom transfer radical polymerization (ATRP), reversible addition-fragmentation transfer polymerization (RAFT), nitroxide-mediated polymerization (NMP), copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) and thiol-ene chemistry. These versatile techniques of polymer synthesis allow the preparation of functional polymeric nanomaterials with well-defined nanostructures and desired functionalities.
Co-reporter:Li Qun Xu;Yi Liang Liu;Koon-Gee Neoh;En-Tang Kang;Guo Dong Fu
Macromolecular Rapid Communications 2011 Volume 32( Issue 8) pp:684-688
Publication Date(Web):
DOI:10.1002/marc.201000765
Co-reporter:Li Qun Xu, Chao Huang, Rong Wang, Koon-Gee Neoh, En-Tang Kang, Guo Dong Fu
Polymer 2011 Volume 52(Issue 25) pp:5764-5771
Publication Date(Web):28 November 2011
DOI:10.1016/j.polymer.2011.10.019
Fluorescent glycopolymers were prepared via combined atom transfer radical polymerization (ATRP) and ‘Click Chemistry’ in one-pot synthesis, in the presence of 2-azidoethyl methacrylate (AzEMA), 2-propynyl α-d-mannopyranoside, N,N′-bis{2-[2-[(2-bromo-2-methylpropanoyl)oxy]ethoxy]ethyl}perylene-3,4,9,10-tetracarboxylic acid bisimide (PBI-Br), copper (I) bromide catalyst and pentamethyldiethylenetriamine (PMDETA) ligand. Simultaneous ATRP and ‘Click Chemistry’ is an attractive method for the synthesis of functional glycopolymers as the reaction conditions are compatible with ATRP of an azide monomer, as long as an alkynyl-functionalized carbohydrate is available for click coupling reaction. The fluorescent glycopolymers were characterized by 1H NMR, FT-IR, UV–visible absorption, fluorescence and X-ray photoelectron spectroscopies, as well as by gel permeation chromatography. Incubation of Escherichia coli (E. coli DH5α) with the fluorescent glycopolymers yielded green fluorescent bacterial clusters. The low cytotoxicity level of the fluorescent glycopolymers was revealed by incubation with 3T3 fibroblasts, macrophages and KB cells in 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assays in vitro. Subsequently, the water-soluble, biocompatible and fluorescent glycopolymers were used as effective fluorescent cell labeling agents.
Co-reporter:Fang Yao, Liqun Xu, Baoping Lin and Guo-Dong Fu
Nanoscale 2010 vol. 2(Issue 8) pp:1348-1357
Publication Date(Web):01 Jun 2010
DOI:10.1039/C0NR00016G
This feature article provides an overview of the preparation of functional nanofibers by combined electrospinning, controlled radical polymerization and ‘Click Chemistry’. A combination of the powerful capability of controlled radical polymerization and ‘Click Chemistry’ for the synthesis of functional macromolecules and on surface modification as well as their wide applicability to electrospinning materials, functional nanofibers with a crosslinked structure, core–shell structures, and switchable surface properties etc. were prepared. In addition, the applications of the functional nanofibers in antibacterial fields and controlled release are also explored.
Co-reporter:Li Qun Xu, Wen Jing Yang, Koon-Gee Neoh, En-Tang Kang, and Guo Dong Fu
Macromolecules 2010 Volume 43(Issue 20) pp:8336-8339
Publication Date(Web):September 27, 2010
DOI:10.1021/ma101526k
Co-reporter:Fang Yao, LiQun Xu, Guo-Dong Fu, and BaoPing Lin
Macromolecules 2010 Volume 43(Issue 23) pp:9761-9770
Publication Date(Web):November 17, 2010
DOI:10.1021/ma102039n
In this work, a kind of semi-interpenetrating polymer network (s-IPN) with unique molecular structures, poly(ethylene glycol) (PEG) network with movable sliding-grafted poly(2-hydroxyethyl methacrylate) (PHEMA) (s-IPN-PEG/α-CD-sg- PHEMA), were first reported. s-IPN-PEG/α-CD-sg-PHEMAs were prepared by simultaneous “click chemistry” and atom transfer radical polymerization (ATRP) of a mixture of poly(ethylene glycol)-diazide/bromobutyryloxy α-cyclodextrin inclusion complex (N3-PEG-N3/(α-CD-BIBB)m), tetrakis(2-propynyloxymethyl) methane (TMOP), CuBr, pentamethyldiethylenetriamine (PMDETA), HEMA and DMF. Attributable to the controlled characters of ATRP and the quantitative yields of “click chemistry”, the prepared s-IPN-PEG/α-CD-sg-PHEMAs have the well-defined PEG networks, as well as uniform and tunable sliding-grafted PHEMA chains. The length of sliding-grafted PHEMA of the s-IPN-PEG/α-CD-sg-PHEMA can be regulated by changing polymerization times. The molecular structures, and physical and thermal properties of the s-IPN-PEG/α-CD-sg-PHEMA were studied by FTIR, 1H NMR, XPS, TGA, and DSC measurements. The s-IPN-PEG/α-CD-sg-PHEMAs exhibit good physical and mechanical properties. Most important, comparing to classical semi-IPN, the diffusion of interpenetrated PHEMA from s-IPN-PEG/α-CD-sg-PHEMA was largely prevented for a long time solvent immersion because the PHEMA brushes were fixed on PEG networks. The sliding-grafted PHEMA chains afford functionalities to the bulk and surface of s-IPN-PEG and could potentially be used as carriers of genes and drugs.
Co-reporter:L. Q. Xu, F. Yao, G. D. Fu and E. T. Kang
Biomacromolecules 2010 Volume 11(Issue 7) pp:
Publication Date(Web):June 2, 2010
DOI:10.1021/bm100268t
Simultaneous interpenetrating polymer networks (sIPNs) from concurrent copper(I)-catalyzed azide−alkyne cycloaddition “click chemistry” and atom transfer radical polymerization (ATRP) are described. Semi-sIPN of poly(ethylene glycol)/poly(2-hydroxyethyl methacrylate) (semi-PEG/PHEMA-sIPN) was first prepared via simultaneous “click chemistry” and ATRP from a mixture of poly(ethylene glycol)-diazide (N3-PEG-N3, Mn = 4000 g/mol), tetrakis(2-propynyloxymethyl)methane (TPOM), ethyl-2-bromobutyrate (EBB), CuBr, pentamethyldiethylenetriamine (PMDETA), and 2-hydroxyethyl methacrylate (HEMA) in dimethylformamide (DMF). Full sIPN of PEG/PHEMA (full-PEG/PHEMA-sIPN) was then prepared via simultaneous “click chemistry” and ATRP from a mixture of N3-PEG-N3 (Mn = 4000 g/mol), TPOM, EBB, CuBr, PMDETA, HEMA, and poly(ethylene glycol) diacrylate) (PEGDA, Mn = 575) in DMF. Both the semi- and full-sIPNs exhibit a fast gelation rate and high gel yield. The sIPNs also exhibit high swelling ratios and good mechanical and antifouling properties. The morphology and thermal behavior of the sIPNs were studied by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). These sIPNs could find applications as biomaterials for contact lenses, biomedical materials, artificial organs, and drug delivery systems.
Co-reporter:Li Qun Xu, Dong Wan, Huifen Flora Gong, Koon-Gee Neoh, En-Tang Kang, and Guo Dong Fu
Langmuir 2010 Volume 26(Issue 19) pp:15376-15382
Publication Date(Web):September 14, 2010
DOI:10.1021/la102775y
A gold substrate with surface-grafted ferrocene functional polymer brushes, or Au-g-PFTMA surface [PFTMA = poly(5-ferrocene-triazolyl methacrylate)], was prepared by a combination of surface-initiated atom transfer radical polymerization (SI-ATRP) and “click chemistry” in one pot, in the presence of 2-azidoethyl methacrylate (AzEMA), ethynyl ferrocene, CuBr catalyst, CuBr2 deactivator, and pentamethyldiethylenetriamine ligand. Thus, SI-ATRP of AzEMA from the Au substrate (the “grafting from” process) and click chemistry of the ethynyl ferrocene to the azide functional group of AzEMA (the “grafting to” process) proceeded simultaneously to produce the functional PFTMA brushes on the Au surface. Kinetic studies suggest that the reaction involving simultaneous SI-ATRP and click chemistry is still consistent with a controlled/“living” process. The composition and physical properties of the modified gold surface were analyzed by X-ray photoelectron spectroscopy, water contact angle measurement, and cyclic voltammetry. The redox-responsive properties of the ferrocene-functionalized polymer brushes on the Au-g-PFTMA surface were demonstrated in the reversible loading−unloading step of the β-cyclodextrin polymer via host−guest interaction.
Co-reporter:G. D. Fu, L. Q. Xu and F. Yao, K. Zhang, X. F. Wang and M. F. Zhu, S. Z. Nie
ACS Applied Materials & Interfaces 2009 Volume 1(Issue 2) pp:239
Publication Date(Web):January 9, 2009
DOI:10.1021/am800143u
A simple method for preparing solvent-resistant nanofibers with a thermal-sensitive surface has been developed by the combined technology of reversible addition-fragmentation chain-transfer (RAFT) polymerization, atom transfer radical polymerization (ATRP), electrospinning, and “click chemistry”. Initially, well-defined block copolymers of 4-vinylbenzyl chloride (VBC) and glycidyl methacrylate (GMA) (PVBC-b-PGMA) were prepared via RAFT polymerization. Electrospinning of PVBC-b-PGMA from a solution in tetrahydrofuran gave rise to fibers with diameters in the range of 0.4−1.5 μm. Exposure to a solution of sodium azide (NaN3) not only affords nanofibers with azido groups on the surface but also leads to a cross-linking structure in the nanofibers. One more step of “click chemistry” between the PVBC-b-PGMA nanofibers with azido groups on the surface (PVBC-b-PGMA−N3) and alkyne-terminated polymers of N-isopropylacrylamide (NIPAM) (PNIPAMAT), which were prepared by ATRP, allows the preparation of a PVBC-b-PGMA nanofiber with thermal-sensitive PNIPAM brushes on the surface (PVBC-b-PGMA-g-PNIPAM). PVBC-b-PGMA-g-PNIPAM nanofibers exhibit a good resistance to solvents and thermal-responsive character to the environment, having a hydrophobic surface at 45 °C (water contact angle ∼140°) and having a hydrophilic surface at 20 °C (water contact angle ∼30°).Keywords: ATRP; click chemistry; cross-linking; electrospinning; polymeric nanofibers; RAFT; solvent-resistant; thermal-sensitive
Co-reporter:Guo-Dong Fu, Li-Qun Xu and Fang Yao, Guo-Liang Li and En-Tang Kang
ACS Applied Materials & Interfaces 2009 Volume 1(Issue 11) pp:2424
Publication Date(Web):October 19, 2009
DOI:10.1021/am900526u
A novel photocontrolled “ON−OFF” release system for the α-cyclodextrin-5-fluorouracial (α-CD−5FU) prodrug, based on host−guest interaction on the photoresponsive and cross-linked nanofiber surface, was demonstrated. The nanofibers with a stimuli-responsive surface were electrospun from the block copolymer prepared via controlled radical polymerization, followed by surface modification via “Click Chemistry”, and loading of the prodrug via host−guest interaction.Keywords: controlled release; cyclodextrin prodrug; host−guest interaction; nanofibers; photoresponsive
Co-reporter:Li Qun Xu, Fang Yao and Guo-Dong Fu, Liang Shen
Macromolecules 2009 Volume 42(Issue 17) pp:6385-6392
Publication Date(Web):August 6, 2009
DOI:10.1021/ma901019r
Simultaneous “click chemistry” and atom transfer radical emulsion polymerization (ATREP) to prepare well-defined macromolecules and cross-linked nanoparticles are first reported in this work. First, simultaneous “click chemistry” and ATREP of styrene were conducted in the presence of p-xylylene diazide, using propargyl 2-bromoisobutyrate (PBiB) as initiator, Tween-20 as emulsifier, copper(I) bromideas catalyst, and pentamethyldiethylenetriamine (PMDETA) as ligand. The simultaneous reactions sharing a same catalyst system gave rise to diblock polystyrene (PS) with controlled molecular weight and narrow molecular weight distribution. The resulting polymers were characterized by gel permeation chromatography (GPC), FT-IR, and 1H NMR spectroscopy. Then, well-defined cross-linked PS nanoparticles with diameter in the range of 50−150 nm were prepared from a simultaneous “click chemistry” and ATREP of a mixed styrene and 4-vinylbenzyl azide using 4,4-bis((2′-bromo-2′-methylpropionyloxy)methyl)-1,6-heptadiyne (BMP) as initiator, Tween-20 as emulsifier, copper(I) bromide as catalyst, and PMDETA as ligand. Well-preserved nanostructures of particles in tetrahydrofuran (THF) and dimethylformamide (DMF) solvents reveal the nanoparticles have a cross-linked structure. The size and morphology of nanoparticles were also characterized by photon correlation spectroscopy and transmission electron microscope. The size of nanoparticles is very uniform and can be regulated by changing the ratio of monomer and initiator as well as the amount of emulsifiers. The cross-linked PS nanoparticles were more thermally stabile than PS from ATREP.
Co-reporter:Fu Guo-Dong, Yao Fang, Li Zhigang and Li Xinsong
Journal of Materials Chemistry A 2008 vol. 18(Issue 8) pp:859-867
Publication Date(Web):17 Jan 2008
DOI:10.1039/B716127A
Diblock copolymers with one block of poly[((2-dimethylamino)ethyl methacrylate)-co-(glycidyl methacrylate)] P(DMAEMA-c-GMA) and another of poly(pentachlorophenyl acrylate) (PPCPA) (P(DMAEMA-c-GMA)-b-PPCPA) were synthesized via consecutive atom transfer radical polymerization (ATRP). Electrospinnning of P(DMAEMA-c-GMA)-b-PPCPA from a solution in THF and DMF gave rise to microfibers with diameters in the range of 300 nm to 1.3 μm. Solvent-resistant microfibers were obtained by the subsequent treatment with 1,6-hexanediamine. The quaternary ammonium salts (QASs) were generated viaN-alkylation of tertiary amine groups of the P(DMAEMA-c-GMA) block by the chloro-aromatic compounds of the PPCPA block (or self-quaternization of P(DMAEMA-c-GMA)-b-PPCPA). Combination of the hydrophobic interaction of the PPCPA and the electrostatic interaction of QASs from the self-quaternization of P(DMAEMA-c-GMA)-b-PPCPA gives the resulting microfibers a high antibacterial activity. The antibacterial effect of the crosslinked microfibers was assayed with Escherichia coli and Staphylococcus aureus cultures. 95% E. coli and 97% S. aureus were killed after being contacted with 50 mg P(DMAEMA-c-GMA)-b-PPCPA microfibers in 10 min. The permanence of the antibacterial activity of the self-quaternized P(DMAEMA-c-GMA)-b-PPCPA microfibers was also demonstrated in repeated applications.
Co-reporter:Fang Yao, Guo-Dong Fu, Junpeng Zhao, En-Tang Kang, Koon Gee Neoh
Journal of Membrane Science 2008 Volume 319(1–2) pp:149-157
Publication Date(Web):1 July 2008
DOI:10.1016/j.memsci.2008.03.049
Microporous polypropylene (PP) hollow fiber (PPHF) membranes with surface-grafted block copolymer brushes of poly(ethylene glycol) monomethacrylate (PEGMA) and 2-(dimethylamino)ethyl methacrylate (DMAEMA) (PPHF-g-(PPEGMA-b-PDMAEMA)) were prepared via consecutive surface-initiated atom transfer radical polymerization (ATRP). The effective pore size of the surface modified PPHF membranes could be adjusted by controlling the graft chain length, or the ATRP time. Quaternization of the tertiary amine groups of the PDMAEMA block with 1-bromododecane gave rise to a high concentration of quaternary amine salt (QAS) on the PPHF membrane surface. The antibacterial effect of the quaternized PPHF-g-(PPEGMA-b-PDMAEMA) membrane was assayed with Escherichia coli (E. coli, a Gram-negative bacterium) and Staphylococcus aureus (S. aureus, a Gram-positive bacterium) cultures. In addition to bactericidal properties, the functionalized membrane surface also exhibited anti-fouling effect for bacteria due to the hydrophilic nature of the P(PEGMA) block on the PPHF-g-(PPEGMA-b-PDMAEMA) membrane. The permanence of antibacterial effect of the functionalized PPHF membrane was also demonstrated in repeated applications of the quaternized PPHF-g-(P(PEGMA)-b-PDMAEMA) membrane.
Co-reporter:G. D. Fu, J. Y. Lei, C. Yao, X. S. Li and F. Yao, S. Z. Nie, E. T. Kang and K. G. Neoh
Macromolecules 2008 Volume 41(Issue 18) pp:6854-6858
Publication Date(Web):August 20, 2008
DOI:10.1021/ma800499h
Co-reporter:Li Qun Xu, Koon-Gee Neoh, En-Tang Kang and Guo Dong Fu
Journal of Materials Chemistry A 2013 - vol. 1(Issue 7) pp:NaN2532-2532
Publication Date(Web):2013/01/08
DOI:10.1039/C2TA01072K
Mercury pollution is a widespread problem. In this work, a solid-state sensor based on rhodamine derivative-modified cellulose filter papers for detection of Hg2+ ions in aqueous media is demonstrated. A three-step approach, involving the introduction of atom transfer radical polymerization (ATRP) initiating sites, surface-initiated ATRP (SI-ATRP) of pentafluorophenyl methacrylate, and post-functionalization of the reactive surface with amino-containing spirolactam rhodamine derivatives in ester–amine reaction, was developed for the covalent immobilization of mercury-responsive probes on the cellulose filter paper. This solid-state sensor exhibits highly selective recognition of Hg2+ ions in a Tris–HNO3 buffer solution (pH = 7.24) over various environmentally relevant metal ions with remarkably enhanced fluorescent emission intensity and distinct color change from colorless to pink. The response of a rhodamine derivative-modified cellulose filter paper to Hg2+ ions is fast (<2 min). The positive fluorescence response and color change of this functionalized filter paper thus provide a disposable solid-state sensor for fluorescent and “naked-eye” detection of Hg2+ ions.
Co-reporter:Fu Guo-Dong, Yao Fang, Li Zhigang and Li Xinsong
Journal of Materials Chemistry A 2008 - vol. 18(Issue 8) pp:NaN867-867
Publication Date(Web):2008/01/17
DOI:10.1039/B716127A
Diblock copolymers with one block of poly[((2-dimethylamino)ethyl methacrylate)-co-(glycidyl methacrylate)] P(DMAEMA-c-GMA) and another of poly(pentachlorophenyl acrylate) (PPCPA) (P(DMAEMA-c-GMA)-b-PPCPA) were synthesized via consecutive atom transfer radical polymerization (ATRP). Electrospinnning of P(DMAEMA-c-GMA)-b-PPCPA from a solution in THF and DMF gave rise to microfibers with diameters in the range of 300 nm to 1.3 μm. Solvent-resistant microfibers were obtained by the subsequent treatment with 1,6-hexanediamine. The quaternary ammonium salts (QASs) were generated viaN-alkylation of tertiary amine groups of the P(DMAEMA-c-GMA) block by the chloro-aromatic compounds of the PPCPA block (or self-quaternization of P(DMAEMA-c-GMA)-b-PPCPA). Combination of the hydrophobic interaction of the PPCPA and the electrostatic interaction of QASs from the self-quaternization of P(DMAEMA-c-GMA)-b-PPCPA gives the resulting microfibers a high antibacterial activity. The antibacterial effect of the crosslinked microfibers was assayed with Escherichia coli and Staphylococcus aureus cultures. 95% E. coli and 97% S. aureus were killed after being contacted with 50 mg P(DMAEMA-c-GMA)-b-PPCPA microfibers in 10 min. The permanence of the antibacterial activity of the self-quaternized P(DMAEMA-c-GMA)-b-PPCPA microfibers was also demonstrated in repeated applications.
