Structural correlation between a crystal and the substrate: A dynamic density functional prediction

Abstract

In material preparing, the freezing on a structured substrate is an important process that determines the molecular structure of the product but the mechanism is still not very clear at present. In this work, we use a dynamic density functional theory (DDFT) to study the freezing of a Lennard-Jones (LJ) fluid on a substrate with a body centered cubic (BCC) structure. We examine the nanostructures of the LJ fluid with different lattice parameter, temperature and adsorption strength. The fluid may freeze into a BCC crystal when the lattice parameter is approximately 1.3 times of the molecular diameter; otherwise, the fluid tends to form into amorphous structures. Supercooling phenomenon has been reproduced by the DDFT, where the fluid forms into a layered structure. It seems the adsorption strength has quantitative instead of qualitative influence on the structure implying that the symmetry is more dominant than the adsorption strength in a crystallization process.