Superelongation of Liquid Metal

Adv Sci (Weinh). 2022 Apr;9(11):e2105289. doi: 10.1002/advs.202105289. Epub 2022 Feb 7.

Abstract

The ability to control interfacial tension electrochemically is uniquely available for liquid metals (LMs), in particular gallium-based LM alloys. This imparts them with excellent locomotion and deformation capabilities and enables diverse applications. However, electrochemical oxidation of LM is a highly dynamic process, which often induces Marangoni instabilities that make it almost impossible to elongate LM and manipulate its morphology directly and precisely on a 2D plane without the assistance of other patterning methods. To overcome these limitations, this study investigates the use of an LM-iron (Fe) particle mixture that is capable of suppressing instabilities during the electrochemical oxidation process, thereby allowing for superelongation of the LM core of the mixture to form a thin wire that is tens of times of its original length. More importantly, the elongated LM core can be manipulated freely on a 2D plane to form complex patterns. Eliminating Marangoni instabilities also allows for the effective spreading and filling of the LM-Fe mixture into molds with complex structures and small features. Harnessing these excellent abilities, a channel-less patterning method for fabricating elastomeric wearable sensors is demonstrated to detect motions. This study shows the potential for developing functional and flexible structures of LM with superior performance.

Keywords: Galinstan; Marangoni instabilities; elongation; liquid metal; wearable sensors.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Oxidation-Reduction
  • Surface Tension*