A multistimuli-responsive recyclable poly(vinyl alcohol)/perylene imide hydrogel of high-performance piezoresistive sensors for human wearable devices

Multiple factors stimulate human beings in their daily lives, but uniformly collecting these signals is challenging. This study proposes a physically cross-linked method that employs hydrogen bonding interactions to prepare poly(vinyl alcohol)/perylene imide (PVA/PI) hydrogels. The prepared PVA/PI hydrogels demonstrate favorable compressive strength (45–75 kPa) and adhesion properties. At room temperature, elongation reaches approximately 400%. Additionally, the PVA/PI hydrogels exhibit strong mechanical properties, with a maximum elongation of 200%, and high ionic-electronic conductivity of 29.6 S m −1 , even after being soaked in a 2 M HCl solution for 24 h. The water-soluble PI in the PVA/PI hydrogels is environmentally responsive, resulting in a current response time of 100 ms under 365 nm irradiation, as well as reversible fluorescence changes across different pH levels. Both the PVA5/PI1 and PVA5/PI1/HCl2 (the concentrations were 5 wt%, 1 mg mL −1 and 2 mol L −1 , respectively) hydrogels demonstrate high sensitivity (0.49 and 7.88 kPa −1 ) and a wide pressure monitoring range (0.088–30.67 kPa and 0.088–18.67 kPa, respectively) as pressure sensors. The first developed recyclable PVA/PI hydrogel shows promise for use in wearable sensing devices and is expected to be applied in complex environments.