The Elastic Mechanical Response of Supported Thin Polymer Films

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• 作者：Peter C. Chung ; Emmanouil Glynos ; Peter F. Green
• 刊名：Langmuir
• 出版年：2014
• 出版时间：December 23, 2014
• 年：2014
• 卷：30
• 期：50
• 页码：15200-15205
• 全文大小：334K
• ISSN：1520-5827

文摘

Nanoindentation studies of the mechanical properties of sufficiently thin polymer films, supported by stiff substrates, indicate that the mechanical moduli are generally higher than those of the bulk. This enhancement of the effective modulus, in the thickness range of few hundred nanometers, is indicated to be associated with the propagation and impingement of the indentation tip induced stress field with the rigid underlying substrate; this is the so-called 鈥渟ubstrate effect鈥? This behavior has been rationalized completely in terms of the moduli and Poisson鈥檚 ratios of the individual components, for the systems investigated thus far. Here we show that for thin supported polymer films, in general, information regarding the local chain stiffness and local vibrational constants of the polymers provides an appropriate rationalization of the overall mechanical response of polymers of differing chemical structures and polymer鈥搒ubstrate interactions. Our study should provide impetus for atomistic simulations that carefully account for the role of intermolecular interactions on the mechanical response of supported polymer thin films.