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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 N-isopropylacrylamide / acrylic acid copolymer (P (NIPAM-co-AA)) shells were synthesized by the first synthesis of PNIPAM microgel core. Core-shell microgels.The thickness of the microgel shell increases with the increase of the stock solution in the shell.The temperature-sensitive volume phase transition behavior of the core-shell microgels at pH = 3.5 has been studied.As PNIPAM core and P (NIPAM -co-AA) shell phase inversion temperature is very close, so only one phase transition was observed.At 3-aminobenzeneboronic acid was reacted with the carboxyl group in the shell by EDC catalysis, the phenylboronic acid group (PBA) was introduced into microgel (NIPAM-co-AMPBA) core-shell structure microgels.The modified microgels showed three volume phase transitions, of which the first corresponds to P (NIPAM- co-AMPBA) shell phase transition.The second and third is the PNIPAM core phase transition process.Because the precipitation reaction of cross-linking agent BIS greater PNIPAM core structure is not uniform, the formation of high BIS content Shell “with a low BIS content is surrounded by a shell of hydrophobic P (NIPAM-co-AMPBA), which widens its” core “and” shell “ ”The phase transition temperature difference, This increase in temperature exhibits two phase transition .PBA modified microgel showed the same sensitivity to glucose, but in the presence of glucose in a small change in degree of swelling.