Melting simulations of poly(ethylene oxide) nanocrystals in amorphous environments

The embedded model has been proposed for simulating melting process of the semicrystalline polymer with a low crystalline fraction. This approach is exemplarily applied to the multiscale coarse-grained (CG) model of poly (ethylene oxide) (PEO) of 14 monomers per chain. When continuously heated to a high temperature, the nanocrystal undergoes great conformational change and disassembly in order. While the specific volume and potential energy of the semicrystalline polymer system capture only glass-rubber transition of amorphous chains, the interaction energy or contact number between the nanocrystal and its amorphous environment allows for precisely identifying glass transition temperature (T-g) and equilibrium melting point (T-m) at the same time. Furthermore, the so-simulated T-g is insensitive to the lateral dimension of the nanocrystal whereas the sosimulated T-m linearly decrease with the inverse of the lateral dimension by the variant of Gibbs-Thomson equation. The extrapolated T-g and T-m for the nanocrystal with infinite lateral dimension compare well with the referenced data. The proposed scheme is quite competitive to the previous ones for a quick and accurate prediction of the T-m of a crystallizing polymer.

Automated summary

The proposed embedded model accurately determines the glass transition temperature and equilibrium melting point of the semicrystalline polymer by considering the interaction energy between the nanocrystal and its amorphous environment, providing a quick and accurate prediction for the T-m of a crystallizing polymer.