侧基和构象能对PDMS分子链无扰尺寸的影响

Effect of disubstitute and conformational energy on unperturbed dimension of PDMS chain

一种基于旋转异构态模型基础上的改进构象统计方法研究聚二甲基硅氧烷链(PDMS)的无扰尺寸.研究结果发现PDMS侧基结构对其短链的均方回转半径特征比影响较大,而长链时构型参数〈S2〉/M值仍趋向于7.76×10-3nm.(g.mol)-1,与实验结果一致.对PDMS链特征比与一级相互作用能的关系作了数值计算,通过对各种模型计算结果的分析,发现如果取旋转异构态模型进行计算,考虑侧基的结构是十分必要的.

An improved confomational statistical method, basd on the rotational-isomeric-state model, was developed in the investigation of unperturbed dimensions of Poly（dimethylsiloxane） （PDMS） chain. It was found that the effect of side groups on the characteristic ratios of mean-square radius of gyration is obvious for the short PDMS chains, and the confomational parameters （S^2） /M of the larger chains about 7.76×10^-3nm·（g·mol）^-1, which agrees with the experiment data. The dependence of the characteristic ratio and the first interaction energy of PDMS is numerically calculated by analyzed the results of various models, we found that it is rather necessary to consider the structure of disubstituted groups if the polymers of rotational-isomeric-state model are calculated.