Liquid metal microchannels as digital sensors in mechanical metamaterials

Abstract

This report explores a synthesis of principles from liquid metal-based flexible electronics and mechanical metamaterials. In such new platforms, mechanical deformation couples with liquid metal microchannels to govern electrical conduction by constriction and release of liquid metal embedded in the soft material. The mechanisms that influence the ability to induce such discrete switch electrical phenomena are identified through studies focused on mechanical design, liquid metal oxidation, and stress thresholds. Through strategic selection of such factors, repeatable switch ability is retained for many stress cycles on the metamaterial, although aging of the phenomena is evident through switch thresholds that reduce with cycles prior to potential failure. These discoveries provide new foundations for self-sensing mechanical metamaterials that leverage an interface of liquid metal coalescence and local mechanical deformation to lead to digital signaling abilities in continuously stressed metamaterials.