A PVDF-based organohydrogel for self-powered and anti-freezing sensor in electronic skin

The self-powered piezoelectric sensor can effectively address the power supply issue for electronic skin. However, it remains challenging to fabricate flexible sensors with a modulus similar to that of human skin. This paper reports a PVDF-based organohydrogels as a piezoelectric senor for electronic skin. PVA serves a primary network, promoting the formation of the electroactive β phase in PVDF and ensuring the piezoelectric performance of the organohydrogel sensor. PA enhances crosslinking density and mechanical properties by forming hydrogen bonds with PVA, while also acting as a gelling agent to reduce PVA crystallization. Additionally, organic solvent DMSO is introduced to impart antifreeze properties to the sensor. The organohydrogel exhibits excellent anti-fatigue performance after 100 compression loading–unloading cycles. Additionally, the organohydrogel piezoelectric sensor demonstrates an impressive response time of approximately 8 ms and a wide pressure range of 0–30 N. Furthermore, the piezoelectric organohydrogel exhibits excellent anti-freezing properties, retaining its mechanical and piezoelectric characteristics even after being frozen at low temperature for 10 days. The PVDF-based organohydrogel has been proven to have significant potential for human motion detection without the need for an external power source.