Nanophase-separated structures of flexible linear amorphous polymers on solids (II) - Molecular dynamics simulation study

In response to the growing demand for precisely controllable nanotechnologies, polymer-based materials are transitioning to the nanometer scale while maintaining their outstanding performance. Enabling further advancements depends on a deeper understanding of the buried polymer melt-solid interface, which governs both structural stability and properties. There is increasing evidence that the nanophase separation of incompatible backbone and side groups, whose typical nanodomain size is about 1 nm, occurs in amorphous polymer melts. Here, we show that a nanophase separation structure of amorphous side-chain polymers is formed on impenetrable solid surfaces using atomistic molecular dynamics simulations and an integrated suite of post-processing techniques. Simulation systems consisting of atactic and isotactic polystyrene and isotactic polypropylene chains on silicon substrates were used as rational models. Simulations were performed with polymer chains consisting of 25 repeating units in the amorphous state. We will discuss the effects of tacticity, side group size, and pi-pi interactions on the formation process of nanophase separated structures in the parallel and perpendicular directions with respect to the substrate surface.