双功能化、双重响应聚（N-异丙基丙烯酰胺）基微凝胶的研究

为制备具有特殊层次结构的多功能化微凝胶，利用N-异丙基丙烯酰胺（NIPAM）为温敏性单体、甲基丙烯酸（MAA）为pH敏感单体、聚乙二醇甲基丙烯酸酯（PEGMA）为反应性稳定剂，通过沉淀聚合合成了内部富含羧基、表面富含羟基的一系列共聚物微凝胶。利用滴定法测定了微凝胶中羧基的含量。透射电镜和动态光散射表明得到的微凝胶几乎是单分散的。变温动态光散射和浊度测定结果表明，所制备的微凝胶具有良好的pH-响应性，随温度改变呈现两级体积相转变。

Study on Bifunctionalized,Dually Responsive Poly(N-Isopropylacrylamide)-Based Microgels

A series of copolymeric microgel,bearing —COOH in the interior and —OH on the surface were designed and synthesized through precipitation copolymerization of N-isopropylacrylamide(NIPAM) as thermosensentive monomer,methacrylic acid(MAA) as pH-sensitive monomer and polyethyleneglycol methacrylate(PEGMA) as reactive stabilizer.The —COOH contents in microgels were measured via Potentiometric and conductimetric titration.Transmission electron microscopy(TEM) and dynamic light scattering(DLS) indicate that nearly monodisperse microgels were obtained.The thermoresponsive behavior of microgels was investigated using variable-temperature DLS technique.The prepared microgels exhibited bimodal volume phase transition,which could be attributed to the hierarchical core-shell structure with —COOH mainly locating in the interior and —OH mainly on the periphery of microgel network.The pH-sensitivity was characterized through turbidimetric method and the prepared microgels exhibited good pH-responsiveness.