Remember the movie Terminator 2? The The T-1000 was a pretty formidable killer robot. We don’t have robots like that yet. But Researchers at NC State have developed a method to make a liquid metal reconfigure its shape. They have pulled it off via electrochemical deposition of an oxide layer on the surface of a liquid metal. Here is how it works:
Liquid metals have very large surface tension and therefore typically adopt a spherical shape. Surfactants, like soap, can lower the interfacial tension between two dissimilar liquids (for example, water and oil), but have negligible impact on the large interfacial tensions of liquid metal… These properties can be harnessed to induce new electrohydrodynamic phenomena for manipulating liquid metal alloys based on gallium, which may enable shape-reconfigurable metallic components in electronic, electromagnetic, and microfluidic devices without the use of toxic mercury.
This is quite a fascinating development. The work was supported by the National Science Foundation. Don’t forget to read the paper, “Giant and Switchable Surface Activity of Liquid Metal via Surface Oxidation,” to find out more information.