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.