Local Chain Dynamics of syndiotactic Poly(methyl methacrylate) Studied by Fluorescence Depolarization Method

Abstract

syndiotactic Poly(methyl methacrylate)s (s-PMMAS) with anthracene in the middle of a main chain were synthesized, and their local motions in dilute solutions were examined by the fluorescence depolarization method. The local motion of two kinds of s-PMMAS with different molecular weights was examined in several low viscosity solvents. The mean relaxation time was measured and the activation energy was evaluated for the local motion of each s-PMMA. First, the effect of the solvent quality on the local chain dynamics was observed. The value of the relaxation time and its activation energy became smaller as the solvent became better one. Secondly the molecular weight dependence of the local motion in poor solvents differs from that in good solvents. In poor solvents, the relaxation time of the local chain became longer as the molecular weight increased, while in a good solvent, the local motion was not influenced by the change of molecular weight. These observations could be explained by the concept of the segment density.