Turing Instability of Liquid-Solid Metal Systems.

The classical Turing morphogenesis often occurs in non-metallic solution systems due to the sole competition of reaction and diffusion processes. Here we conceived that gallium (Ga)-based liquid metals possess the ability to alloy, diffuse, and react with a range of solid metals and thus should display Turing instability leading to a variety of nonequilibrium spatial concentration patterns. We disclosed a general mechanism for obtaining labyrinths, stripes, and spots-like stationary Turing patterns in the liquid-solid metal reaction-diffusion systems (GaX-Y), taking the gallium indium alloy and silver substrate (GaIn-Ag) system as a proof of concept. It is only when Ga atoms diffuse over Y much faster than X while X reacts with Y preferentially, that Turing instability occurs. In such a metallic system, Ga serves as an inhibitor and X as an activator. The dominant factors in tuning the patterning process include temperature and concentration. Intermetallic compounds contained in the Turing patterns and their competitive reactions have also been further clarified. This liquid metal Turing instability mechanism opens many opportunities for constructing micro-structure systems utilizing condensed matter to experimentally explore the general morphogenesis process. This article is protected by copyright. All rights reserved.