中文摘要：

提出了一种通过乳化剂复配简便制备表面包覆率可调的核-壳复合微球的方法.高效液相色谱和zeta电位测试结果表明,核粒子和壳粒子在分散混合过程中出现了乳化剂吸附和脱附的再平衡现象,从核粒子表面游离的阳离子乳化剂与壳粒子表面的阴离子乳化剂发生电性中和作用,导致核、壳2种粒子的zeta电位值互相接近,基于静电作用的异相凝聚失效.进一步研究发现,在保持核粒子分散液中乳化剂总量为1 wt%的前提下,添加非离子乳化剂既可以确保分散体系的稳定性,又可以调控阳离子乳化剂的游离量,成功实现核-壳复合微球的异相凝聚.由此可见,通过调节复配乳化剂中阳离子与非离子乳化剂的配比,可简便地调控复合微球的表面包覆率.还探讨了异相凝聚体系中p H值和电解质浓度对核-壳复合微球表面包覆率的影响.

英文摘要：

A facile approach for preparing core-shell composite microspheres with tunable surface coverage was proposed. High performance liquid chromatography and zeta potential results showed that, rebalancing of emulsifiers＇ adsorption and desorption occurred when core and shell particles were mixed, and the cationic emulsifier desorbed from the core particle might neutralize the anionic emulsifier on the surface of shell particles. This resulted in a low gap of the zeta potential values between the core and the shell particles, and led to fail of the electrostatic-induced heteroeoagulation. It was found that both the stability of the dispersion system and the contents of the free cationic emulsifier could be regulated by adding nonionic emulsifier. Subsequently,the heterocoagulation was successfully achieved as the contents of total emulsifier were kept at 1 wt%. Thus, by adjusting the ratio of nonionic and cationic emulsifier content, the surface coverage of composite microspheres could be easily controlled. The influence of pH value and electrolyte content on the surface coverage of core-shell composite microspheres was also discussed in this work.