PEDOT-molecular bridging foam-hydrogel based wearable triboelectric nanogenerator for energy harvesting and sensing

Abstract

Conductive hydrogels, due to their adjustable flexibility and conductivity, present considerable advantages in tackling the bottleneck issues associated with electron transfer in wearable electronic devices. However, during the deformation process, achieving effective electron transfer between the hydrogel electrode and the adjacent frictional piezoresistive sensing layer, as well as effective transmission within the hydrogel electrode itself, remains a significant challenge. Herein, PEDOT molecular bridging is proposed to establish an efficient connection between hydrogel electrode and the adjacent layer. Polyacrylamide integrated with PEDOT interpenetrating network-based hydrogel (PPNM) is prepared as electrode through synergistic dual-crosslinking. A repetitive vacuum-assisted dip-coating technique is employed to modify TPU foam scaffolds with silver nanowire (AgNW) and PPNM, resulting in TPU@AgNW@PPNM foam (TAP) with a three-dimensional dual-conductive network as the adjacent frictional piezoresistive sensing layer. By tightly integrating TAP with PPNM, a mutual PEDOT-bridging between TAP and PPNM is established. Importantly, the interface remains intact and ensures stable electron transmission even under significant stretching and bending conditions. The piezoresistive sensor and triboelectric nanogenerator assembled based on TAP and PPNM exhibited an enhanced sensitivity of 27.8 kPa⁻¹ and an output power density of 3.1 mW m⁻², respectively. This innovative solution effectively addresses the critical issue of electronic transfer between the electrode layer and the adjacent layer in wearable electronic devices, while also mitigating the problems related to the rigidity of electrodes that can impact the flexibility and comfort of wearable devices.