017. Multiscale modeling of glass transition in polymeric films: Application to stereoregular poly(methyl methacrylate)s
writer：Chaofu Wu
keywords：Multiscale simulations; Glass transition temperature; Poly(methyl methacrylate) films
source：期刊
specific source：Polymer 2018; 146: 91-100
Issue time：2018年
The multiscale modeling scheme has been extended to derive the coarse-grained potentials for simulating glass transition temperatures (Tg) of the bulks and the freely-standing films of two stereoregular poly (methyl methacrylate) (PMMA) configurations. The extensive molecular dynamics simulations reasonably reproduce the volumetric properties. Furthermore, the “dynamical Tg” sensibly exhibits the Flory-Fox relation with molecular-weight or film-thickness, which is not revealed by the “volumetric Tg”. Thus, for either of the PMMA bulks, the experimental Tg and the simulated (dynamical) Tg values obey a linear scaling relation, which is used to infer the actual Tg of the film. Consequently, syndiotactic PMMA films show greater Tg depressions from the bulks than the isotactic PMMA films at the same thicknesses, which is in good agreements with the experimental observations. Such a computational framework holds a bright promise to quantitatively predict Tg values and related properties of various confined polymer systems.
https://www.sciencedirect.com/science/article/pii/S0032386118304324