Nucleation and Growth on Curved Surfaces

L. R. GÓMEZ

Leiden

Seminario; Soft Matter Seminar - Leiden University; 2014

Insituut Lorentz - Leiden University

Ordered phases lying on curved substrates are not only commonly found in nature in systems like viral capsids, insect eyes, pollen grains, radiolaria, and others, but can also be obtained in the laboratory in the form of crystal or liquid crystal phases by using colloids, block copolymers, liquid crystals, and possibly other self-assembled systems. Although experiments and theoretical calculations have contributed to unveil the equilibrium configurations of these systems, dynamical processes like crystallization, melting, and other transitions remains largely unexplored. In this talk we present a simple theoretical description of nucleation and growth of two-dimensional phases lying on arbitrarily curved backgrounds. The model is based on a coarse-grained Guinzburg-Landau free energy functional and a phase-field evolution equation. We show how the curvature of the substrate affects the critical size of propagating nuclei and the minimum energy path towards the equilibrium phase. In general nucleation and growth will be faster on regions of positive curvature, where the height of barriers for nucleation are smaller. Substrates of varying curvature can originate complexities in the free energy landscape for nucleation, inducing the formation of local barriers where initially propagating nuclei may become stabilized and trapped by the underlying curvature.