Evaporation-induced pattern formation of decanol droplets

Pattern formation in far from equilibrium systems is observed in several disciplines including biology, geophysics, and reaction-diffusion chemistry, comprising both living and nonliving systems. We aim to study such non-equilibrium dynamics on a lab-scale with materials of simple composition. We present a novel system based on a 1-decanol droplet placed in a solution of alkaline decanoate. Previously we showed short time scale behavior of this system, which included chemotaxis and maze-solving. Here we explore long time scale dynamics of the system (several hours) when open to the environment. We observe dramatic morphological changes in the droplet including long tentacular structures, and we analyze the morphology of these structures at both the macroscopic and microscopic scale across a large range of initial conditions. Such reproducible morphological changes in simple droplets open a path for exploration of shape-based effects in larger scale pattern formation studies.