两端系留纳米粒子聚合物的分子动力学模拟  

Molecular Dynamics Simulation of Polymers Tethered with Nanoparticles at Two Ends

作　　者：王文清 王立权[1] Wen-qing Wang;Li-quan Wang(School of Materials Science and Engineering,East China University of Science and Technology,Shanghai 200237)

机构地区：[1]华东理工大学材料科学与工程学院,上海200237

出　　处：《高分子学报》2023年第12期1935-1942,共8页Acta Polymerica Sinica

基　　金：国家自然科学基金(基金号22173030,21774032)资助项目.

摘　　要：两端系留纳米粒子聚合物是研究末端对聚合物链弛豫行为影响的优选分子模型.本文构建了两端系留纳米粒子聚合物模型,运用粗粒化分子动力学方法研究了两端系留纳米粒子聚合物的特征温度和弛豫行为,探讨了纳米粒子半径和聚合物链长对玻璃化转变温度、结晶温度和介电性能的影响.研究表明,聚合物两端纳米粒子的存在可延缓聚合物链的弛豫并促进结晶,使两端系留纳米粒子聚合物的玻璃化转变温度和结晶温度均增加.研究结果与相关的实验报道吻合,可加深对两端系留纳米粒子聚合物结构和性能的理解.The polymer tethered with nanoparticles at two ends is a preferred molecular model for studying the effect of the chain end on the relaxation behavior of polymers.We constructed a polymer model with two nanoparticles tethered at each end and used coarse-grained molecular dynamics to study the characteristic temperature and relaxation behavior of these polymers.The effects of nanoparticle radius and polymer length on the glass transition temperature,crystallization temperature,and dielectric properties were examined.We found that two apparent transitions occur during the annealing.The high-temperature transition corresponds to the crystallization due to the existence of nanoparticles at ends,and the low-temperature transition is the glass transition related to polymer chains.The presence of nanoparticles at both ends of the polymer can delay the relaxation of the polymer chain and promote crystallization,resulting in an increase in the glass transition temperature and crystallization temperature of the polymer as the nanoparticle becomes large or the polymer chain shortens.The chain relaxation was further studied by calculating the relaxation correlation functions and dielectric relaxation spectra.The work revealed that the dielectric loss peak shifts towards low frequencies as the nanoparticle radius increases or the polymer chain length decreases.We finally compared the simulation results with existing experimental findings,and an agreement was achieved.The work can deepen the understanding of the structure and properties of the polymer with two nanoparticles tethered at each end.

关 键 词：弛豫 玻璃化转变 分子动力学 聚合物接枝纳米粒子 

分 类 号：TB383.1[一般工业技术—材料科学与工程] TQ317[化学工程—高聚物工业]