Collagen-based breathable, humidity-ultrastable and degradable on-skin device

Abstract

Realizing simultaneous high breathability and humidity stability of on-skin devices is still a critical challenge. Herein, we develop a breathable, humidity-ultrastable and degradable sensory skin by using cowskin as a skin-friendly substrate. Cowskin has similar constituents and hierarchical structure to human skin, which supplies the sensory skin with remarkable breathability and exceptional water-vapor permeability as high as 3714 g m⁻² d⁻¹, two orders of magnitude larger than conventional polydimethylsiloxane film (80 g m⁻² d⁻¹). Sensory skin features a distinct sensing mechanism that employs cowskin as a cross-scale deformable 3D sensory substrate for achieving high skin-conformability, detection sensitivity (0.144 kPa⁻¹), fast response (200 ms), high operational stability (15 000 cycles) and wide sensory range from human physiological signals to high strain movements. Because sensory skin relies on a 3D sensory structure, its sensing ability is, therefore, free from a localized structure damage, including scratches, cuts and abrasions. Sensory skin is further processed to be superhydrophobic, gaining unaffected sensory capability under extremely humid conditions (50 °C and relative humidity of 82%) with exceptional breathability (1087 g m⁻² d⁻¹). The collagenous substrate of sensory skin is fully degradable. These outstanding advantages make sensory skin a powerful skin-friendly on-skin device.