This self-sorting coating cools wearable electronics by up to 21.6°F without any power

Researchers developed a stretchable coating that automatically separates into a sunlight-reflective aluminum oxide layer and a heat-conducting liquid-metal layer.

The power-free coating lowered peak circuit temperatures by up to 15.1°F indoors and 21.6°F outdoors.

Applied to a wearable heart-rate monitor, it substantially improved photoplethysmography signal accuracy outdoors and after exercise.

The approach could reduce overheating in skin-worn devices while preserving stretchability and improving outdoor biometric readings.