A Flexible Tough Hydrovoltaic Coating for Wearable Sensing Electronics.

The lack of a strong binding mechanism between nanomaterials severely restricts the advantages of the evaporation-driven hydrovoltaic effect in wearable sensing electronics. It is a challenging task to observably improve the mechanical toughness and flexibility of hydrovoltaic devices to match the wearable demand without abandoning the nanostructures and surface function. Here, a flexible tough polyacrylonitrile/alumina (PAN/Al O ) hydrovoltaic coating with both good electricity generation (open-circuit voltage, V  ≈ 3.18 V) and sensitive ion sensing (2285 V M for NaCl solutions in 10 to 10  m) capabilities is developed. The porous nanostructure composed of Al O nanoparticles is firmly locked by the strong binding effect of PAN, giving a critical binding force 4 times that of Al O film to easily deal with 9.92 m s strong water-flow impact. Finally, skin-tight and non-contact device structures are proposed to achieve wearable multifunctional self-powered sensing directly using sweat. The flexible tough PAN/Al O hydrovoltaic coating breaks through the mechanical brittleness limitation and broadens the applications of the evaporation-induced hydrovoltaic effect in self-powered wearable sensing electronics.