A gelatin-based ionogel with anti-swelling properties for underwater human physiological signal detection.

A hydrogel is an ideal matrix material for flexible electronic devices, electronic skin and health detection devices due to its outstanding flexibility and stretchability. However, hydrogel-based flexible electronic devices swell once they are placed in a high humidity or underwater environment. The swelling behavior could damage the internal structure of hydrogels, ultimately leading to the reduction or complete loss of mechanical properties, electrical conductivity and sensing function.