Choi Jihoon, Clarke Nigel, Winey Karen I, Composto Russell J
Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania, United States.
Department of Physics and Astronomy, University of Sheffield, Sheffield, S3 7RH, United Kingdom.
ACS Macro Lett. 2014 Sep 16;3(9):886-891. doi: 10.1021/mz500344h. Epub 2014 Aug 22.
Polymer nanocomposites (PNCs) have characteristic length scales associated with both the nanoparticles (i.e., size and interparticle distance) and the polymer molecules (i.e., tube diameter of entanglement and radius of gyration; ). When the nanoparticle (NP) and polymer length scales are comparable, the polymer dynamics exhibit contrasting behavior for NPs differing only in size and shape. For spherical NPs and short anisotropic NPs, the polymer diffusion coefficient decreases monotonically with NP concentration. However, for long anisotropic NPs, polymer diffusion slows down at low NP concentration and recovers for NP concentrations above the critical concentration for network formation. By spanning intermediate ranges of nanoparticle size and shape, the role of the NP geometric parameters on the polymer dynamics is substantially advanced, thereby providing new routes toward controlling polymer dynamics and viscoelasticity of PNCs.
聚合物纳米复合材料（PNCs）具有与纳米颗粒（即尺寸和颗粒间距离）以及聚合物分子（即缠结的管直径和回转半径）相关的特征长度尺度。当纳米颗粒（NP）和聚合物的长度尺度相近时，对于仅在尺寸和形状上不同的NP，聚合物动力学表现出截然不同的行为。对于球形NP和短的各向异性NP，聚合物扩散系数随NP浓度单调降低。然而，对于长的各向异性NP，聚合物扩散在低NP浓度下减慢，而在高于网络形成的临界浓度的NP浓度下恢复。通过跨越纳米颗粒尺寸和形状的中间范围，NP几何参数对聚合物动力学的作用得到了显著提升，从而为控制PNCs的聚合物动力学和粘弹性提供了新途径。
