核壳结构葡萄糖敏感微凝胶的制备  

SYNTHESIS OF GLUCOSE-SENSITIVE CORE-SHELL MICROGELS

作　　者：关英[1] 罗巧芳[1] 张拥军[1] 

机构地区：[1]南开大学化学学院高分子化学研究所功能高分子材料教育部重点实验室,天津300071

出　　处：《高分子学报》2010年第3期280-284,共5页Acta Polymerica Sinica

基　　金：科技部国际科技合作项目(基金号2007DFA50760);教育部博士点基金新教师项目(基金号20070055079)资助项目

摘　　要：用先合成聚N-异丙基丙烯酰胺(PNIPAM)微凝胶核再包一层N-异丙基丙烯酰胺/丙烯酸共聚物(P(NIPAM-co-AA))壳的办法合成了一系列核壳结构微凝胶.微凝胶壳层厚度随投入的壳储备溶液的增加而增加.研究了pH=3.5时核壳微凝胶的温敏体积相转变行为.由于PNIPAM核和P(NIPAM-co-AA)壳的相转变温度很接近,因此只观察到一个相转变.在EDC催化下使3-氨基苯硼酸与壳层中的羧基反应,将苯硼酸基(PBA)引入微凝胶,得到核为PNIPAM、壳为P(NIPAM-co-AMPBA)的核壳结构微凝胶.改性后的微凝胶表现出3个体积相转变过程.其中第一个对应于P(NIPAM-co-AMPBA)壳层的体积相转变.第二和第三个则是PNIPAM核的相转变过程.由于在沉淀聚合时交联剂BIS反应性更大,PNIPAM核结构不均一,形成BIS含量高的"核"和BIS含量低的"壳".BIS含量低的"壳"被一层疏水的P(NIPAM-co-AMPBA)壳包裹,拉大了其与"核"的相转变温度的差别,因此随着温度升高表现出两个相转变过程.PBA改性的微凝胶同样表现出葡萄糖敏感性,但在葡萄糖存在下溶胀度的改变较小.A series of core-shell microgels with a poly-（N-isopropylacrylamide） （PNIPAM） core and a poly-（N-isopropylacrylamide-co-acrylic acid） （P（NIPAM-co-AA）） shell were synthesized. The shell thickness increases with the increasing feeding of the shell solution. The thermosensitive phase transition behavior of these microgels was studied at pH=3.5. Only one phase transition was observed because the volume phase transition temperature （VPTT） of the core was close to that of the shell. Phenylboronic acid （PBA） groups were introduced by EDC coupling of 3-aminophenylboronic acid with carboxylic acid in the shell of the microgel. Three phase transitions were observed in the PBA-modified core-shell microgels. The first one was attributed to the transition of the shell, while the second and the third transitions reflected a heterogeneous structure of the core which originated from the fast incorporation of the BIS crosslinker during precipitation polymerization. The VPTT difference between the BISrich “core” and the BIS-poor “shell” was enlarged by the coverage of the hydrophobic P（NIPAM-co-AMPBA） shell. The glucose-sensitivity of the PBAmodified core-shell microgels was revealed by their increasing hydrodynamic radii in the presence of glucose, however, the increase in particle size was limited because of the non-glucose-sensitive core. The phase transition behavior of the PBA-modified core-shell microgels in the presence of glucose was also studied. With increasing glucose concentration, the VPTT of the shell increased and approached to that of the core. As a result, the coreshell microgels presented only one transition at high glucose concentrations.

关 键 词：聚N-异丙基丙烯酰胺 微凝胶 核-壳结构 葡萄糖敏感 

分 类 号：O648.17[理学—物理化学] O631.3[理学—化学]