Mei Baicheng, Dell Zachary E, Schweizer Kenneth S
ACS Macro Lett. 2021 Oct 19;10(10):1229-1235. doi: 10.1021/acsmacrolett.1c00530. Epub 2021 Sep 24.
We construct a segmental scale force level theory for the center-of-mass diffusion constant and corresponding relaxation time for globally compact unconcatenated ring polymer solutions and melts (degree of polymerization ). The approach is based on slowly decaying macromolecular scale intermolecular force dynamic correlations as the origin of their unusual dynamics. Unentangled Rouse, weakly caged, and activated regimes are predicted. The barrier of the activated regime scales linearly with and as a power law of concentration, which drives a kinetic glass transition on the radius-of-gyration scale. The values of at the two dynamic crossovers (Rouse to weakly caged, weakly caged to activated) are proportional, with nonuniversality entering mainly via macromolecular volume fraction and dimensionless compressibility. Quantitative comparisons with simulation data reveal good agreement. Aspects of intermediate time dynamics are analyzed, and predictions are made for the conditions required to observe a macromolecular glass transition in the laboratory and on the computer.
我们构建了一个关于全局紧密、未连接的环状聚合物溶液和熔体（聚合度）的质心扩散常数及相应弛豫时间的分段标度力水平理论。该方法基于大分子尺度分子间力动态关联的缓慢衰减，将其视为聚合物异常动力学的起源。预测了非缠结的Rouse区、弱笼蔽区和活化区。活化区的势垒与聚合度呈线性关系，并与浓度呈幂律关系，这在回转半径尺度上驱动了动力学玻璃化转变。两个动态转变点（从Rouse区到弱笼蔽区、从弱笼蔽区到活化区）处的聚合度值成比例，非普适性主要通过大分子体积分数和无量纲压缩性体现。与模拟数据的定量比较显示出良好的一致性。分析了中间时间动力学的各个方面，并对在实验室和计算机上观察大分子玻璃化转变所需的条件进行了预测。
