Interfacial mobility of polymers on inorganic solids.
Interfacial mobility of polymers on inorganic solids.
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DOI：
10.1021/jp810370f
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发表时间：
2009-03
期刊：
影响因子：
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通讯作者：
Keiji Tanaka;Y. Tateishi;Yohei Okada;T. Nagamura;M. Doi;H. Morita
中科院分区：
文献类型：
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作者：
Keiji Tanaka;Y. Tateishi;Yohei Okada;T. Nagamura;M. Doi;H. Morita
一个典型的无定形聚合物，聚苯乙烯，在与固体基质的界面处的链段流动性的非侵入性检查荧光寿命测量使用倏逝波激发结合粗粒度分子动力学模拟。玻璃化转变温度（T（g））在界面处明显高于内部体相区。在不同入射角的激发脉冲的测量表明，T（g）变得更接近界面。随着聚合物和固体基质之间界面处的自由能差异的增加，梯度变得更加显著。界面处的T（g）值随着分子量的减小而减小。然而，由于基质对链端部分的限制，界面T（g）的降低不如本体T（g）的降低那么多。最后，观察到当膜变得薄于50 nm时，界面处的降低的迁移率与由表面的存在引起的增强的迁移率耦合。实验结果与仿真结果雅阁较好。
The segmental mobility of a typical amorphous polymer, polystyrene, at the interfaces with solid substrates was noninvasively examined by fluorescence lifetime measurements using evanescent wave excitation in conjunction with coarse-grained molecular dynamics simulation. The glass transition temperature (T(g)) was discernibly higher at the interface than in the internal bulk region. Measurements at different incident angles of excitation pulses revealed that T(g) became higher closer to the interface. The gradient became more marked with an increasing difference in the free energy at the interface between the polymer and solid substrate. The T(g) value at the interface decreased with decreasing molecular weight. However, the decrement for the interfacial T(g) was not as much as that for the bulk T(g), due to the restriction of chain end portions by the substrate. Finally, it was observed that when a film became thinner than 50 nm, the depressed mobility at the interface coupled with the enhanced mobility induced by the presence of the surface. The experimental and simulation results were in good accord with each other.