链刚性和剪切场对纳米棒在纳米复合体系中分布和取向的影响

纳米粒子在聚合物熔体中的分布规律备受关注。采用分子动力学模拟方法研究了纳米棒在聚合物熔体中的分布和取向行为。当高分子链与纳米棒间的相互作用较弱时，纳米棒呈直接接触聚集状态，不利于纳米复合材料性能的改善。当逐渐提高高分子链刚性时，纳米棒的分散程度略有提高；当向纳米复合体系施加剪切场并达到一定强度时，纳米棒的分散程度明显提高。在适当的链刚性和剪切场作用下，纳米棒不仅分散状态良好，而且呈一定的取向分布，纳米复合材料的性能得到较大提高。

Effects of chain stiffness and shear flow on nanorod distribution and orientation in polymer melts

The distribution of nanoparticles in polymer melts is concerned by many researchers.In this paper,the molecular dynamics simulations method is used to investigate the dispersion and orientation of nanorods in polymer melts.We study the influence of the interfacial interaction between the polymer chain and the nanorods on the distribution of nanorod,and solved the relationship between chain stiffness and nanorod dispersion and orientation under the action of the shear flow.While at low interfacial interaction between the polymer chain and the nanorods,it exhibits a direct contact aggregation,which greatly prevents the realization of excellent performance of nanocomposites.With the increase of the chain stiffness,the dispersion of nanorods is slightly increased.Compared with the increase of the chain stiffness,the shear flow not only can greatly improve the dispersion of nanorods but also control the degree of nanorod orientation well.Especially in the semi-flexible polymer melts,one can expect to see the improved orientation and dispersion of nanorods in polymer melts under the shear flow.