聚甲基丙烯酸甲酯单分子膜的静、动态弹性

通过测量分析两个不同分子量的聚甲基丙烯酸甲酯(PMMA)单分子膜的π-A等温线及其微分曲线,讨论了PMMA单分子膜成膜过程和分子量对膜相变状态的影响,并用动态膜障振动法测量了PMMA单分子膜的动态弹性.结果表明,分子链的相互作用(如扭曲和缠绕)在膜的形成中起着重要的作用,并影响膜的静、动态性质.单分子膜的静、动态弹性都有两相特性,且前者比后者小.随着分子量的增大,膜的凝聚性和稳定性都增强,静、动态弹性都增大.

Static and Dynamic Elasticities of PMMA Monolayers

Based on measuring and analyzing the π-A isotherms and their differentiate curves for monolayers of polymethyl methacrylate(PMMA) with different molecular weights, the formation and the effect of molecular weight on the phase transition of PMMA monolayers were discussed in detail. The dynamic elasticity of each monolayer was determined by barrier oscillation method and compared with its static elasticity. It is showed that the interactions such as skew and twist of the macromolecular chains have a great effect on the formation and the static and dynamic behavior of PMMA monolayer. Both of the static and dynamic elasticities are biphasic and the former is much smaller than the latter in general. With increasing molecular weight, the condensability and stability become more obvious and the static and dynamic elasticities are larger.