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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pH值和电解质浓度对核-壳复合微球表面包覆率的影响.
A new method for preparation of core-shell composite microspheres with adjustable surface coverage was proposed by the compounding of emulsifier.The results of HPLC and zeta potential showed that the core and shell particles appeared in the process of dispersion and mixing The phenomenon of rebalance between adsorption and desorption of emulsifier, the neutralization of cationic emulsifier free from the surface of the core particle and the anionic emulsifier on the surface of the shell particle leads to the zeta potential values of the two kinds of core and shell particles close to each other, Electrostatic interaction heterogeneous coagulation failure further study found that the core particle dispersion to maintain the total amount of 1 wt% of the premise, the addition of non-ionic emulsifier can not only ensure the stability of the dispersion, but also regulate the cationic emulsification Agent free volume, the successful realization of heterogeneous aggregation of core-shell composite microspheres.Thus, by adjusting the ratio of cationic emulsifier with non-ionic emulsifier can be easily regulated composite microspheres surface coating The effects of pH value and electrolyte concentration on the surface coverage of the core-shell composite microspheres were also discussed.