Phase-Transition-Driven Adaptive Reconfiguration of Wearable Devices for Conformal Biointerfaces.

Abstract

Conformal integration of flexible electronics with unstandardized biological tissues is critical for next-generation wearables. However, flexible devices are predominantly fabricated in conventional planar formats, incompatible with the nonplanar, hairy, or dynamic surfaces of biological organisms. Here, we resolve this conflict by introducing a universal solid-liquid-solid phase transition strategy. This approach utilizes water-soluble polyvinyl alcohol as a substrate, which temporarily liquefies and flows to match target topography upon wetting, then solidifies in place, enabling a perfect conformal interface. Such a process helps the reconstructed devices to establish robust (interfacial toughness ∼29 J m^-2, tensile strength of ∼161 kPa), stretchable, and stress-free interfaces with skin. Furthermore, this robust interface permits reversible switching between strong to weak adhesion, while dissolving on-demand for painless, non-traumatic removal. We validate the approach with shape-adaptable sensors and electrodes that seamlessly wrap the vulnerable, peristaltic bodies of silkworms for motion tracking, and hairy, thorn-laden leaves for plant electrophysiology monitoring, expanding the utility of wearable electronics to previously inaccessible biological surfaces.