自组装制备PEG接枝聚苯乙烯微球的粒径控制

用苯乙烯封端的聚乙二醇(St—PEG)大单体与苯乙烯(St)进行接枝共聚，将得到的双亲性接枝共聚物(PEG—g—PSt)逐步滴加到各种比例的甲醇／水的混合溶剂中，通过该聚合物在混合溶剂中的自组装，制得了PEG—g—PSt微球。用透射电子显微镜(TEM)和激光光散射(LLS)对微球的形态和粒径进行了表征。实验结果表明，改变接枝液组成、接枝液浓度、滴加速度以及混合溶剂组成等反应条件可有效地控制所得微球的粒径及其分布。

PARTICLE SIZE CONTROL OF POLY(ETHYLENE GLYCOL)-g-POLYSTYRENE NANOPARTICLES PREPARED BY ASSEMBLY METHOD

The PEG grafted polystyrene (PEG-g-PSt) copolymers were prepared by the copolymerization of styrene with PEG macromonomer having a styrol end group for one polymer chain. The resulting copolymer can self-assemble to form the polymeric nanoparticles in the methanol/water mixed solvent. The nanoparticles have a hydrophobic core (polystyrene chains) and hydrophilic branches (polyethylene glycol chains) on their surfaces based on the assembling mechanism. So, the hydrophilic chains work as the dispersing agent. The diameter, size distribution and form of the nanoparticles were characterized by using transmission electron microscopy (TEM) and laser light scattering (LLS). The results show that the parameters such as reaction solvent, concentration of PEG-g-PSt, the feed rate, water content in the mixed solvent all affect the particle size of the nanoparticles. Also, the particle size of nanoparticles can be controlled from 50 nm to 500 nm in diameter.