Coarse-grained molecular modeling of the microphase structure of polyurea elastomer

POLYMER

卷:176

Article

Liu, Minghao¹  Oswald, Jay¹ 

[1] Arizona State Univ, Sch Engn Matter Transport & Energy, Tempe, AZ 85287 USA

关键词: Coarse-grained model;    Microphase separation;    Iterative Boltzmann inversion;   

DOI  :  10.1016/j.polymer.2019.04.039

来源: Elsevier

【 摘 要 】

We present a structure-matching coarse-grained model of polyurea, similar to united atom models, in which hydrogen atoms are implicitly represented. The model was trained using iteration Boltzmann inversion and a new heuristically-determined, distance-dependent scaling function that dramatically reduces the iterations required. With its reduced complexity and accelerated dynamics, the coarse-grained model can simulate microphase separation with hard domain spacing of 5 nm, comparable to x-ray scattering measurements of similar polyurea elastomers. An analysis of the morphology of two model systems shows a large, interconnected hard domain within a multiblock system, compared to an interrupted hard phase composed of separate smaller ribbon-shaped domains in a diblock system. To analyze the topology of soft segment connectivity, we calculated their end-to-end distribution, revealing that soft segments are composed of a large population of bridge-like segments and a smaller population of loop-like segments.

【 授权许可】

Free