Comb-Type Grafted Hydrogels of PNIPAM and PDMAEMA with Reversed Network-Graft Architectures from Controlled Radical PolymerizationsReport as inadecuate




Comb-Type Grafted Hydrogels of PNIPAM and PDMAEMA with Reversed Network-Graft Architectures from Controlled Radical Polymerizations - Download this document for free, or read online. Document in PDF available to download.

CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026, China





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Academic Editor: Nicolay V. Tsarevsky

Abstract Dual thermo- and pH-responsive comb-type grafted hydrogels of polyN,N-dimethylaminoethyl methacrylate PDMAEMA and polyN-isopropylacrylamide PNIPAM with reversed network-graft architectures were synthesized by the combination of atom transfer radical polymerization ATRP, reversible addition-fragmentation chain transfer RAFT polymerization and click chemistry. Two kinds of macro-cross-linkers with two azido groups at one chain-end and different chain length PNIPAM–N32 and PDMAEMA–N32 were prepared with N,N-diβ-azidoethyl 2-halocarboxylamide as the ATRP initiator. Through RAFT copolymerization of DMAEMA or NIPAM with propargyl acrylate ProA using dibenzyltrithiocarbonate as a chain transfer agent, two network precursors with different content of alkynyl side-groups PDMAEMA-co-ProA and PNIPAM-co-ProA were obtained. The subsequent azido-alkynyl click reaction of macro-cross-linkers and network precursors led to the formation of the network-graft hydrogels. These dual stimulus-sensitive hydrogels exhibited rapid response, high swelling ratio and reproducible swelling-de-swelling cycles under different temperatures and pH values. The influences of cross-linkage density and network-graft architecture on the properties of the hydrogels were investigated. The release of ceftriaxone sodium from these hydrogels showed both thermal- and pH-dependence, suggesting the feasibility of these hydrogels as thermo- and pH-dependent drug release devices. View Full-Text

Keywords: hydrogels; stimuli-sensitive polymers; ATRP; RAFT; click chemistry; network-graft architecture hydrogels; stimuli-sensitive polymers; ATRP; RAFT; click chemistry; network-graft architecture





Author: Sheng-Qi Chen, Jia-Min Li, Ting-Ting Pan, Peng-Yun Li and Wei-Dong He *

Source: http://mdpi.com/



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