核-壳结构P(AM-co-MAA)-W-Ag复合微球的制备

以丙烯酰胺(acrylamide, AM)和甲基丙烯酸(methacrylic acid, MAA)的共聚微凝胶(P(AM-co-MAA))为模板, 通过离心沉积法将钨粉沉积于高分子微凝胶表面, 得到具有核-壳结构的P(AM-co-MAA)-W复合微球; 再以经聚乙烯基吡咯烷酮(PVP)修饰的P(AM-co-MAA)-W复合微球为模板, 在硝酸银溶液中充分溶胀后, 通过向反相悬浮体系中缓慢通入氨气, 制备得到了具有核-壳结构的P(AM-co-MAA)-W-Ag双金属复合微球材料. 实验发现, 通过改变制备过程中AgNO3的初始浓度和PVP的用量等条件, 可以改变复合微球表面银的沉积量; 并结合实验结果初步提出了银的形成机理, 即PVP的存在, 不仅可以作为稳定剂固定Ag+离子, 同时可以作为还原剂促进Ag+还原为Ag的反应.

Preparation of P(AM-co-MAA)-W-Ag Composite Microspheres with Core-Shell Structures

A method of preparing poly(acrylamide-co-methacrylic acid)-tungsten-silver (P(AM-co-MAA)-W-Ag) composite microspheres with core-shell structures by a copolymer microgel template was described. P(AM-co-MAA)-W composite microspheres were fabricated by centrifugal deposition of tungsten powder on the surface of the polymer template. After absorbing a layer of poly(vinylpyrrolidone) (PVP) on the template of P(AM-co-MAA)-W microspheres and fully immersing them in the AgNO3 aqueous solution, P(AM-co-MAA)-W-Ag composite microspheres were prepared slowly by introducing ammonia gas in the reverse suspension system. It was demonstrated that varying the concentrations of PVP and AgNO3 could modulate the deposition amount of silver on the surface of microspheres. Furthermore, the elementary mechanism of the formation of silver was proposed. The PVP acts both as a stabilizing agent and a reducing agent for the deposition of metal Ag particles.