Generalized way to make temperature tunable conductor–insulator transition liquid metal composites in a diverse range†
Liquid materials with the ability to transit between conductor and insulator are of great scientific and practical significance. However, achieving the conduction of a liquid metal droplet network is still a challenge. To solve these problems, a generalized method is proposed to fabricate temperature tunable liquid conductor–insulator transition composites, which is achieved firstly via freezing and thawing liquid metal droplets dispersed in dimethicone. Such composites also impart conductivity to the dispersed liquid metal droplet network. To illustrate the typical application of the thus realized materials, a visualized circuit is constructed based on the relationship between the color and the conduction. In addition, reconfigurable and repairable circuits are fabricated depending on the inherent liquid properties of these materials. Furthermore, this universal mechanism has been revealed via the abnormal volume expansion ratio of the liquid metal droplets during the phase change. By calculating the volume change ratio of all metals, we speculate and confirm that gallium-based alloys and bismuth-based alloys can be used to prepare such conductive transition materials. Accordingly, we identify more eligible materials with suitable phase transition points, which significantly extends the transition temperature from insulator to conductor. The liquid material preparation strategy proposed here provides a novel paradigm for achieving the conductor–insulator transition at a wide temperature range and offers promising potential for future applications.