Tube Curvature Slows the Motion of Rod-Coil Block Copolymers through Activated Reptation.
Tube Curvature Slows the Motion of Rod-Coil Block Copolymers through Activated Reptation.
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DOI：
10.1021/mz5007377
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发表时间：
2015-01
影响因子：
5.8
通讯作者：
Muzhou Wang;A. E. Likhtman;B. Olsen
中科院分区：
文献类型：
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作者：
Muzhou Wang;A. E. Likhtman;B. Olsen
了解具有复杂形状的分子的动力学对于研究人员使用混合分子开发先进材料非常重要。本研究应用滑动弹簧模型，以可视化和量化的缠结动力学的棒-线圈嵌段共聚物。通过与分子动力学模拟结果的匹配确定了模型参数。通过监测聚合物沿着缠结管的位置，棒-线圈共聚物显示出不利于其中棒占据由线圈端部产生的随机变化曲率的管的弯曲部分的配置。这证实了共聚物的爬行是通过活化机制发生的，并且是先前通过模拟和实验通过扩散测量推断的活化屏障的第一个证明。扩散的障碍进一步量化通过考虑环形聚合物的曲线运动，和它们对扩散的影响是定量捕获通过考虑一维运动沿着缠结管与粗糙的自由能势。
Understanding the dynamics of molecules with complex shapes is important as researchers develop advanced materials using hybrid molecules. This study applies a slip-spring model to visualize and quantify the entangled dynamics of rod-coil block copolymers. The parameters of the model are determined by matching with molecular dynamics simulation results. By monitoring the positions of polymers along the entanglement tube, rod-coil copolymers are shown to disfavor configurations where the rod occupies curved portions of the tube of randomly varying curvature created by the coil ends. This confirms that reptation of copolymers occurs by an activated mechanism and is the first demonstration of the activation barriers that have been previously inferred through diffusion measurements by simulation and experiment. The barriers to diffusion are further quantified by considering the curvilinear motion of ring polymers, and their effect on diffusion is quantitatively captured by considering one-dimensional motion along an entanglement tube with a rough free energy potential.