聚合物纳米微粒静电组装行为及其表征

使用2,2′-偶氮二异丁基脒二盐酸盐自由基引发剂,改变甲基丙烯酰氧乙基十六烷基二甲基溴化铵阳离子功能单体的量与苯乙烯进行乳液聚合获得不同粒径的阳离子乳胶粒,使用十二烷基硫酸钠为乳化剂和过硫酸钾为引发剂制备阴离子聚合物乳胶粒.采用基于静电相互作用的异凝聚法将以上2种带有相反电荷的乳胶粒组装,获得了表面粗糙程度不同的复合微粒.对异凝聚过程中复合液透光率和微粒大小及分布进行跟踪测试,并用透射电子显微镜表征了阳离子微粒、阴离子微粒以及复合微粒的形态和大小.结果表明,在一定范围内可以通过控制阴离子乳胶粒与阳离子乳胶粒的复合比例改变单个复合微粒表面阳离子小微粒的数目.

ASSEMBLY PROCESS OF POLYMER NANOPARTICLES AND THEIR CHARACTERIZATION

Preparation of raspberry-like polymer composite particles through adherence of smaller cationic particles of P(St-co-DMHB) (poly(styrene-co-methacryloxyethylhexadecyldimethylammonium bromide)) onto larger PMMA (poly(methyl methacrylate)) anionic particles surface was achieved by heterocoagulation based on electrostatic interaction.A series of P(St-co-DMHB) cationic particles with particle size varied from 43 nm to 105 nm were obtained through emulsion polymerization using different levels of the cationic monomer DMHB.The particles were assembled on the anionic particles surfaces respectively to result in polymer composite particles having different granulations.Light transmittance and particle size and its distribution in the heterocoagulation processes were followed in order to clarify in detail the assembling process of the small cationic polymer particles onto the larger anionic polymer particles.Transmission electron microscope was used to examine the morphologies of the cationic latex particles,the anionic latex particles and that of the composite particles after their heterocoaguculation.It was observed that the degree of coverage of the small cationic particles on the surface of the anionic large particles was adjustable in a range by varying the ratio of the anionic and the cationic latex particles.