Cephalopod-inspired soft composite with liquid metal inclusions for tunable infrared modulation

Abstract

Artificial adaptive soft infrared (IR) materials, mimicking the color-changing abilities observed in soft organisms such as cephalopods, hold significant promise in various emerging technologies, including unconventional flexible displays, intelligent camouflage systems, and advanced sensors. In this study, we integrated inherently deformable liquid metal (LM) microdroplets randomly into an elastomer matrix, creating a fully soft material that exhibits elastic compliance akin to soft biological tissue and adaptive IR-reflecting properties in response to compression. Under compressive strains, each LM inclusion behaves as a unit of dynamic IR reflector, transitioning between a contracted droplet with a corrugated surface and an expanded plate-like filler with a relatively smooth surface. These alterations in shape, size, and surface structure allow dynamic modulation of incident IR radiation’s reflection, resulting in reversible changes in IR color (i.e., detected temperature). This mechanism replicates the dynamic alterations observed in cephalopod skin, where chromatophores dynamically manipulate visible light reflection by changing their size and morphology. We demonstrate proof-of-concept applications of this material, showing its ability to modify IR appearance through compression for visualization, with its localized color-change mechanism enabling its use as a tactile sensor in vision-based tactile grippers. These illustrate the potential of this material in emerging adaptive flexible electronics.