Superhydrophobic and high-performance wood-based piezoresistive pressure sensors for detecting human motions

Abstract

To promote the sustainable development of modern society, the functional wood-based materials have been one of the most promising candidates to alleviate the deterioration of environment by partially replacing the polymer materials derived from petroleum. However, the hydrophilicity of natural wood greatly limited its practical applications. Herein, a superhydrophobic and conductive wood sponge (P-rGO@WS) for piezoresistive pressure senor is fabricated through chemical treatment, coverage and reduction of graphene oxide (GO) and subsequent modification by polydimethylsiloxane (PDMS). The wood-based sensor exhibits high sensitivity up to 4.93 kPa−1 in 0–5 kPa and a fast response time of 160 ms. Owing to the effective stress transfer by the ordered lamellar architecture with arched layers and the mechanical compressibility improved by the rGO and PDMS layers, the sensor maintains stable electrical response even after undergoing 1000 compression cycles at a strain of 60%, illustrating the excellent fatigue resistance. Moreover, the sensor possesses superhydrophobicity with a high water contact angle of 152° and still remains superhydrophobic state even under compression. Importantly, the sensor is successfully applied for detecting human motions including wrist pulse, voice recognition and various body activities. The findings conceivably stand out a sustainable method to fabricate high-performance piezoresistive pressure senor derived from biomass materials for wearable electronics even under humid environment.