线形、梳形和星形高分子静态和动态性质的模拟

以梳形高分子为纽带,基于粗粒化分子动力学模拟方法,研究了线形、梳形和星形拓扑结构高分子的静态和动态性质,以揭示稀溶液中高分子链行为与链拓扑结构依赖关系的一般性规律.研究结果表明,随着线形-梳形-星形的链拓扑结构转变,回转半径的标度关系由仅依赖分子聚合度转变为同时依赖链聚合度与臂数或侧链数.分析了星形高分子和梳形高分子的静态和动态性质的特征规律.星形高分子的臂数增加使其尺寸迅速减小,形状则由长椭球形转变为类球形,且扩散系数也随之增加;其均方回转半径(〈R_g〉)和扩散系数(D)与分子聚合度(N)及臂数(f)的标度规律为〈R_g〉~N~(0.581)f~(-0.402),D~N~(-0.763)f~(0.227).梳形高分子的静态与动态性质与分子聚合度及侧链数的依赖关系为〈R_g〉~N~(0.597)f~(-0.212)(每个支化点只有一条侧链)和〈R_g〉~N~(0.599)f~(-0.316)(每个支化点有多条侧链).

Simulation on the Static and Dynamic Properties of Linear,Comb-like and Star-like Polymers

We studied the static and dynamic properties of linear, comb-like and star-like polymers by means of molecular dynamics method. We found star-like polymers had the smallest size, and linear polymers had the largest size at the same chain length. Changing the chain topologies from linear to comb-like and star-like will lead to the great dependence of the scaling relationship of radius of gyration on both the degree of polymeriza-tion and the number of side chains or the arms. For star polymers, the increase of the number of arms results inthe decrease of the radius of gyration and increase of the diffusion coefficients. Moreover, the scaling relationship for radius of gyrations for star polymers and comb polymer is also obtained. These results may help people understand the physical insight of the topological structure dependence on the static and dynamic properties of polymer chains.