Fractal structure of the crystalline-nuclei boundaries in 2D colloidal crystallization: Computer simulations

By performing 2D kinetic Monte Carlo simulations of colloidal crystallization we found that the boundaries of the crystalline nuclei are not only rough, as obtained by experimentalists, but fractal, whose value (dfdf) we calculated. The corresponding boundary for the crystals, above the critical size (NcNc), is also fractal but smoother. A knowledge of the particles coordinates during the crystallization process allows us to calculate the NcNc, the line tension (γ) and the chemical potential difference (Δμ) between the two phases. However, different from the experimentalists procedure, we found that the boundary fractalities are needed to derive γ and Δμ.

► First time observation/evaluation of fractal boundaries of crystallites and crystals.
► Correct obtention of the boundary tension using the fractal boundary length.
► Correct obtention of the chemical potential difference using the fractal dimensions.
► Smoother boundaries of the crystals compared to rougher crystallites, explained.