VISCOELASTIC DYNAMICS OF CONFINED POLYMER MELTS
VISCOELASTIC DYNAMICS OF CONFINED POLYMER MELTS
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DOI：
10.1126/science.258.5086.1339
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发表时间：
1992-11-20
期刊：
影响因子：
56.9
通讯作者：
GRANICK, S
中科院分区：
文献类型：
--
作者：
HU, HW;GRANICK, S
描述了限制在吸附表面（平行云母板）之间的聚甲基硅氧烷熔体（聚苯基甲基硅氧烷）的频率相关剪切响应。正弦变形足够小，以给出线性响应，这意味着测量没有扰动膜结构。随着厚度的减小，观察到显著的转变。当薄膜厚度小于未扰动回转半径的五到六倍时，出现了强的橡胶样弹性，这不是大块样品的特征。这一结果表明，增强缠结的相互作用在薄的聚合物膜，并提供了一种机制来解释聚合物在表面的缓慢流动性。
The frequency-dependent shear response of an ultrathin polymer melt (polyphenylmethylsiloxane) confined between adsorbing surfaces (parallel plates of mica) is described. The sinusoidal deformations were sufficiently small to give linear response, implying that measurement did not perturb the film structure. A remarkable transition was observed with decreasing thickness. When the film thickness was less than five to six times the unperturbed radius of gyration, there emerged a strong rubber-like elasticity that was not characteristic of the bulk samples. This result indicates enhanced entanglement interactions in thin polymer films and offers a mechanism to explain the slow mobility of polymers at surfaces.