Surface-grafted block copolymer brushes with continuous composition gradients of poly(poly(ethylene glycol)-monomethacrylate) and poly(N-isopropylacrylamide)  

作　　者：LI LinHui WU JinDan GAO ChangYou 

机构地区：[1]MOE Key Laboratory of Macromolecular Synthesis and Functionalization,Department of Polymer Science and Engineering,Zhejiang University,Hangzhou 310027,China

出　　处：《Science China Chemistry》2011年第2期334-342,共9页中国科学(化学英文版)

基　　金：supported by the National Natural Science Foundation of China (20934003,20774084);the National Basic Research Program of China (973Program,2005CB623902)

摘　　要：Surface-grafted block copolymer brushes with continuous composition gradients containing poly(poly(ethylene glycol) monomethacrylate) (P(PEGMA)) and poly(N-isopropylacrylamide) (PNIPAAm) chains were fabricated by integration of the surface-initiated atom transfer radical polymerization (SI-ATRP) and continuous injection method. Three types of copolymer gradients were prepared: (1) a uniform P(PEGMA) layer was block copolymerized with a gradient PNIPAAm layer (PP1); (2) a gradient P(PEGMA) layer was block copolymerized with a uniform PNIPAAm layer (PP2); and (3) a gradient P(PEGMA) layer was inversely block copolymerized with a gradient PNIPAAm layer (PP3). The as-prepared gradients were characterized by ellipsometry, water contact angle and atomic force microscopy (AFM) to determine their alterations in thickness, surface wettability and morphology, confirming the gradient structures. In vitro culture of HepG2 cells was implemented on the gradient surfaces, revealing that the cells could adhere at 37 ℃ and be detached at 20 ℃. Introduction of the PEG chains as an underlying layer on the PNIPAAm grafting surfaces resulted in faster cell detachment compared with the PNIPAAm grafting surface.Surface-grafted block copolymer brushes with continuous composition gradients containing poly(poly(ethylene glycol) monomethacrylate) (P(PEGMA)) and poly(N-isopropylacrylamide) (PNIPAAm) chains were fabricated by integration of the surface-initiated atom transfer radical polymerization (SI-ATRP) and continuous injection method.Three types of copolymer gradients were prepared: (1) a uniform P(PEGMA) layer was block copolymerized with a gradient PNIPAAm layer (PP1);(2) a gradient P(PEGMA) layer was block copolymerized with a uniform PNIPAAm layer (PP2);and (3) a gradient P(PEGMA) layer was inversely block copolymerized with a gradient PNIPAAm layer (PP3).The as-prepared gradients were characterized by ellipsometry,water contact angle and atomic force microscopy (AFM) to determine their alterations in thickness,surface wettability and morphology,confirming the gradient structures.In vitro culture of HepG2 cells was implemented on the gradient surfaces,revealing that the cells could adhere at 37 °C and be detached at 20 °C.Introduction of the PEG chains as an underlying layer on the PNIPAAm grafting surfaces resulted in faster cell detachment compared with the PNIPAAm grafting surface.

关 键 词：gradients ATRP PNIPAAM cell attachment THERMO-RESPONSIVE 

分 类 号：O631.3[理学—高分子化学]