交联剂用量对阳离子微凝胶合成及性能的影响

Effect of the Amount of Cross-Linker on Synthesis and Properties of Cationic Microgel

以甲基丙烯酸二乙基氨基乙酯(DEAMA)为阳离子单体,聚乙二醇甲基丙烯酸酯(PEGMA)为大分子稳定剂,通过调节交联剂二甲基丙烯酸乙二醇酯(EGDMA)的用量,采用乳液聚合法制备了一系列具有pH响应性的阳离子微凝胶PDEAMA.利用透射电镜(TEM)、电位-电导滴定、动态光散射仪(DLS)等手段,对微凝胶的形貌、pK_a值、pH响应性等进行了表征.研究表明这类阳离子型微凝胶具有很好的pH响应性,在pH=7左右发生相转变;随着交联剂用量的增加微凝胶稳定性和pK_a值变小,pH响应性变弱,质子化时的Zeta电位降低.

A series of cationic microgels with pH-response were synthesized by emulsion polymerization with poly （ethylene glycol） methacrylate （PEGMA） macromolecular as the stabilizer, 2- （diethylamino） ethyl methacrylate （DEAMA） as cationic monomer, and a bifunctional ethylene glycol dimethacrylate （EGDMA） as cross-linker. Different amount of cross-linker on the effects of synthesis and properties of microgels were studied in detail. The resultant microgels were characterized by transmission electron mi- croscopy （TEM）, dynamic light scattering （DLS） and potentiometric titrations. The pH-responsive be- havior of the microgels was investigated by the measurements of hydrodynamic diameter and Zeta poten- tials of the microgels at different pH values. It was demonstrated that the cationic microgels had well pH-responsive property, and the phase variation happened around pH = 7. Increasing the amount of EGDMA cross-linker would lead to a progressively lower elective pKa, stability and pH-responsibility of the microgels.