Universal Scaling of Polymer Diffusion in Nanocomposites.
Universal Scaling of Polymer Diffusion in Nanocomposites.
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DOI：
10.1021/mz400064w
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发表时间：
2013-03
影响因子：
5.8
通讯作者：
Jihoon Choi;Michael J. A. Hore;J. Meth;N. Clarke;K. Winey;R. Composto
中科院分区：
文献类型：
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作者：
Jihoon Choi;Michael J. A. Hore;J. Meth;N. Clarke;K. Winey;R. Composto
纳米颗粒是一种新型的有价值的添加剂，可以很好地调节高分子材料的热、机械、电学、光学和磁性能。纳米颗粒的加入还可以增强或减缓聚合物动力学，这取决于混合物的热力学和关键长度尺度，即纳米颗粒大小、颗粒间距（ID）和聚合物的旋转半径（Rg）。目前，理解纳米颗粒如何影响聚合物动力学的框架是不可用的，部分原因是缺乏广泛的实验研究。本文研究了示踪剂在模型纳米复合材料中的扩散，该模型纳米复合材料含有接枝聚合物刷（软纳米颗粒）或短配体（硬纳米颗粒）的二氧化硅纳米颗粒。在广泛的示踪剂分子量和纳米颗粒负载范围内，当与约束参数（定义为ID/Rg）绘制时，归一化扩散系数在软纳米颗粒和硬纳米颗粒的通用曲线上收缩，该参数说明了示踪剂渗透到电刷中的情况。这些实验结果为构建纳米复合材料中聚合物动力学预测模型所需的基本原理提供了新的见解。
Nanoparticles are new and valuable additives that can favorably tune thermomechanical, electric, optical, and magnetic properties of polymeric materials. The addition of nanoparticles can also enhance or slow down polymer dynamics depending on the mixture thermodynamics and key length scales, namely, nanoparticle size, interparticle spacing (ID), and the polymer radius of gyration (Rg). Presently, a framework for understanding how nanoparticles affect polymer dynamics is not available, in part, because of a lack of wide-ranging experimental studies. Here, tracer diffusion is studied in model nanocomposites containing silica nanoparticles grafted with either polymer brushes (soft nanoparticles) or short ligands (hard nanoparticles). Over a wide range of tracer molecular weights and nanoparticle loadings, the normalized diffusion coefficient collapses onto a universal curve for both soft and hard nanoparticles when plotted against a confinement parameter, defined as ID/Rg, which accounts for tracer penetration into the brush. These experimental results provide new insights into the fundamental principles required to construct predictive models of polymer dynamics in nanocomposites.