"Chameleon Metals" Change Surfaces in Response to Heat

Researchers at Iowa State University have developed "chameleon metals"—materials that change their surface structure in response to heat. By treating liquid metal alloys with controlled heating, scientists observed the formation of tiny spheres and nanowires, altering the metal's surface texture. This breakthrough could lead to smart alloy systemscapable of evolving their surface properties for applications in sensing, catalysis, and material engineering.

Key Findings

• Liquid metal alloys of gallium, indium, and tin were synthesized into particles with a smooth oxide shell.

• As heat was applied, the surface thickened and stiffened, behaving more like a solid.

• At higher temperatures, the surface fractured, allowing different metals to emerge sequentially—gallium first, followed by indium, and finally tin at 1,600°F.

• This process enables continuous inversion of composition, making the metal responsive to thermal stimuli.

• The ability to program surface textures could revolutionize material science, offering new possibilities for adaptive and self-regulating alloys.

Andrew Martin et al, Chameleon Metals: Autonomous Nano-Texturing and Composition Inversion on Liquid Metals Surfaces, Angewandte Chemie International Edition(2019). DOI: 10.1002/anie.201912639