Biphasic liquid metal mixtures in stretchable and flexible applications

Abstract

Liquid metals (LMs) have emerged as key materials for soft and wearable electronics owing to their unique properties such as fluidity, deformability, low toxicity, high electrical and thermal conductivities, self-healing, and biocompatibility. Moreover, LMs can be mixed with other metal particles and soft materials to form two-phase structures. Wearable and stretchable electronic devices can utilize biphasic LM mixtures as a material with different characteristics from those of conventional LMs. Biphasic LM mixtures consist of solid and liquid phases which are defined, respectively, as LM with solid metal particles and LM inside a soft material. An LM with solid metal particles consists of an alloy of LM and a metal such as Ni or Cu. In contrast, an LM with a soft material is composed of LM and an elastomer such as polydimethylsiloxane (PDMS) or Ecoflex. Sensors and field-effect transistors (FETs) utilizing two-phase LM mixtures are discussed in this paper. Additionally, fabrication and patterning of two-phase LM mixtures are discussed.