Effects of chemically heterogeneous nanoparticles on polymer dynamics: insights from molecular dynamics simulations,Soft Matter

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Effects of chemically heterogeneous nanoparticles on polymer dynamics: insights from molecular dynamics simulations
Soft Matter ( IF 2.9 ) Pub Date : 2018-01-02 00:00:00 , DOI: 10.1039/c7sm02414b
Zijian Zheng _{1,

2,

3,

4,

5} , Fanzhu Li _{1,

2,

3,

4,

5} , Jun Liu _{1,

2,

3,

4,

5} , Raffaele Pastore _{6,

7,

8,

9,

10} , Guido Raos _{9,

11,

12,

13} , Youping Wu _{1,

2,

3,

4,

5} , Liqun Zhang _{1,

2,

3,

4,

5}

Affiliation

The dispersion of solid nanoparticles within polymeric materials is widely used to enhance their performance. Many scientific and technological aspects of the resulting polymer nanocomposites have been studied, but the role of the structural and chemical heterogeneity of the nanoparticles has just started to be appreciated. For example, simulations of polymer films on planar heterogeneous surfaces revealed unexpected, non-monotonic activation energy to diffusion on varying the surface composition. Motivated by these intriguing results, here we simulate via molecular dynamics a different, fully three-dimensional system, in which the heterogeneous nanoparticles are incorporated in a polymer melt. The nanoparticles are roughly spherical assemblies of strongly and weakly attractive sites, in fractions of f and 1 − f, respectively. We show that the polymer diffusion is still characterized by a non-monotonic dependence of the activation energy on f. The comparison with the case of homogeneous nanoparticles clarifies that the effect of the heterogeneity increases on approaching the polymer glass transition.

中文翻译：

化学异质纳米颗粒对聚合物动力学的影响：分子动力学模拟的见解

固体纳米颗粒在聚合物材料中的分散被广泛用于增强其性能。已经研究了所得聚合物纳米复合材料的许多科学和技术方面，但是刚刚开始认识到纳米颗粒的结构和化学异质性的作用。例如，在平面异质表面上对聚合物薄膜进行的模拟显示出意想不到的非单调活化能，可以在改变表面成分时扩散。由于这些有趣的结果，在这里，我们通过分子动力学模拟了一个不同的，完全三维的系统，该系统将异质纳米粒子掺入了聚合物熔体中。纳米粒子是具有强和弱吸引力的部位的大致球形组件，其比例为f和1- f。我们表明，聚合物扩散仍然以活化能对f的非单调依赖性为特征。与均质纳米颗粒的情况的比较表明，异质性的影响在接近聚合物玻璃化转变时增加。

更新日期：2018-01-02

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