Preparation and micellization of block copolymers (PS-b-PMMA) of various chain lengths

• Main Authors: Je-Yuan Yeh, 葉哲源
• Other Authors: Hou-Hsein Chu
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/60953132945619439186

碩士 === 逢甲大學 === 化學工程學所 === 95 === Polystyrene-b-polymethyl mathacrylate (PS-b-PMMA) copolymers with various block chain lengths were prepared via stable free-radical polymerization (SFRP). Acetone and toluene were used as the solvent, respectivety, to study the micellization. The micellar types and sizes depend on the relative chain lengths of two blocks. The critical micellar concentraction (CMC) was determined by using the Du Nouy’s tensionmeter, the micellar size was decided by using the dynamic light scttering (DLS), and the size and shape of micelle was also determined by using scanning electron microscope (SEM). Although the molecular weight increases with conversion , we found that the polymerization is not exclusively ”living”.The hydrodynamic radius of eatch block copolymer was determined by using DLS at concentraction below CMC. It was found that the aggregation may have size deviate from the normal dimension for either the micellar size or the single molecular size. The calculation found that the micelle was constituted of fewer molecules when the polymer has the larger solvo- philic chain length.