Enhanced mobility of confined polymers
Enhanced mobility of confined polymers
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DOI：
10.1038/nmat2031
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发表时间：
2007-12-01
期刊：
影响因子：
41.2
通讯作者：
Russell, Thomas P.
中科院分区：
文献类型：
--
作者：
Shin, Kyusoon;Obukhov, Sergei;Russell, Thomas P.
由对分子施加空间约束所带来的非经典行为，正在为新的应用开辟道路。例如，碳纳米管显示了小分子在纳米管中的快速和选择性传输，作为有机溶剂或气体分子的生物或化学分离材料具有巨大的潜力(1-5)。对于聚合物，当限制体积的尺寸远远小于旋转半径时，对几何约束对链动力学的扰动的定量理解仍然是一个挑战(6-10)，随着纳米制造工艺的发展，限制聚合物的动力学具有重大的技术意义(11-17)。在这里，我们描述了限制在纳米圆柱孔内的聚合物的弱分子量依赖的迁移率，所述纳米圆柱孔的直径小于主体中的链的尺寸。根据孔轴上的链构型，测得聚合物在受限几何构型中的迁移率远高于非受限链的迁移率。随着基于聚合物流动的纳米加工工艺的出现，流动的意外增强和分子间纠缠的减少在加工策略的设计和执行中具有重要意义。
Non-classical behaviour, brought about by a confinement that imposes spatial constraints on molecules, is opening avenues to novel applications. For example, carbon nanotubes, which show rapid and selective transport of small molecules across the nanotubes, have significant potential as biological or chemical separation materials for organic solvents or gaseous molecules(1-5). With polymers, when the dimensions of a confining volume are much less than the radius of gyration, a quantitative understanding of perturbations to chain dynamics due to geometric constraints remains a challenge(6-10) and, with the development of nanofabrication processes, the dynamics of confined polymers have significant technological implications(11-17). Here, we describe a weak molecular-weight-dependent mobility of polymers confined within nanoscopic cylindrical pores having diameters smaller than the dimension of the chains in the bulk. On the basis of the chain configuration along the pore axis, the measured mobility of polymers in the confined geometry is much higher than the mobility of the unconfined chain. With the emergence of nanofabrication processes based on polymer flow, the unexpected enhancement in flow and reduction in intermolecular entanglements are of significant importance in the design and execution of processing strategies.