双功能化、双重响应聚(N-异丙基丙烯酰胺)基微凝胶的研究

摘要

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 Po-tentiometric 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.%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.