AI Article Synopsis
- The study uses high-frequency oscillations in a coarse-grained polymer model to investigate local dynamic mechanical properties of free-standing polymer thin films.
- It is discovered that soft layers form near the surfaces of glassy thin films as the temperature nears the glass transition point, which decreases the overall stiffness of the film with increased thickness.
- Two distinct regions are observed in films at the bulk glass transition temperature: a melt-like region near the surfaces and a glass-like region in the middle, highlighting a heterogeneous distribution of mechanical properties.
Article Abstract
High-frequency sinusoidal oscillations of a coarse-grained polymer model are used to calculate the local dynamic mechanical properties (DMPs) of free-standing polymer thin films. The storage modulus G(') and loss modulus G(") are examined as a function of position normal to the free surfaces. It is found that mechanically soft layers arise near the free surfaces of glassy thin films, and that their thickness becomes comparable to the entire film thickness as the temperature approaches the glass transition T(g). As a result, the overall stiffness of glassy thin films decreases with film thickness. It is also shown that two regions coexist in thin films just at the bulk T(g); a melt-like region (G(')
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| http://dx.doi.org/10.1063/1.1873732 | DOI Listing |
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