聚苯乙烯微球表面电解质高分子刷的表征

Characteristics of Electrolyte Brushes on Surface of Polystyrene Particles

通过光乳液聚合制备表面带有PAA电解质高分子刷的聚苯乙烯微球,水解将高分子刷"剪裁"下来进行直接的表征。考察表面毛发的分子量、接枝密度随时间等因素的变化,了解微球表面聚合物链的生长机理。结果表明,微球表面的聚合物链的分子量从光照40min到光照120min基本不随时间变化。接枝密度从40min到80min迅速增大,导致壳层厚度的增大。因此,在微球表面,高分子刷的增长遵循自由基聚合机理。单体AA的加入量从50%增加到150%,接枝一根链所用面积相应从54.5nm2增加到74.5nm2。种子微球的浓度从0.2%增加到2.0%,接枝一根链所用面积相应从66.2nm2减小到46.0nm2。

The PS particles with PAA eletrolyte brushes were prepared by photoemulsion polymerization, then the brushes were cutted from the PS particles by hydrolysis and were characterized. The molecular weight of the brushes and grafting density on different conditons were studied to find the growing mechanism of polymer chains on the surface of particles. The results indicted that the molecular weight of the chains did not change from 40 minutes to 120 minutes. With the time increasing, the grafting density increased from 40 minutes to 80 minutes. As a result, the thickness of brushes shell was increased. So , on the surface of the particles the growth of brushes followed the radical polymerization. Furthmore, the grafting density change from 54. 5nm^2 to 74. 5 nm^2 with the content of AA. However, with the added seeds increased, the grafting density change from 66.2 nm^2 to 46. 0 nm^2.