In-situ observation of DL-alanine crystallization from a laser-trapped dense liquid droplet as a heterogeneous nucleation site

Abstract

Abstract Nucleation from an aqueous solution is an important step in crystallization which controls the physicochemical properties of crystalline materials. Although dense liquid droplets are considered as a precursor of a crystal in the two-step nucleation model, their actual role is unclear. Our in-situ microscopic observations of the crystallization of DL-alanine from a dense liquid droplet trapped by laser tweezers show that liquid droplets play the role of a substrate, facilitating heterogeneous nucleation, rather than a precursor of a crystal.