Hydrogel-infiltrated micropatterned nano-carbon aerogel sheet composed of partially carbonized cellulose nanofibers for wearable sensor

Abstract

It is still a challenge to establish a continuous electronic conductive network for conventional conductive hydrogels served for high-sensitive and comfortably wearable sensors. In this study, a micropatterned hybrid sheet, approximately 1 mm thick, was developed by infiltrating a multifunctional hydrogel precursor within a micropatterned nano-carbon aerogel sheet composed of partially carbonized cellulose nanofibers before gelatinization. The aerogel sheet, designed with parallel rectangular grooves and ridges, has a slightly lower modulus than the hydrogel. The hydrogel, gelatinized within the aerogel sheet in a glycerol-water binary system, features a dual-crosslinked network of bacterial cellulose and a hydrophobically associated copolymer. This design allows the hydrogel to absorb most of the stress during stretching, while the nano-carbon aerogel sheet undergoes controlled crack propagation, leading to uneven deformation and localized stress concentration. This unique stress-handling mechanism imparts the hybrid sheet with a gauge factor (GF) of 12.3ε¹^.²⁷ up to 1000 % strain, pressure sensitivity (S) of 31.33p^−0.71 in the 0–500 kPa range, humidity sensing capacity and exceptional cycling stability over 1000 cycles under 200 % strain or 50 kPa pressure. The sensor enables precise real-time health monitoring, rehabilitation, disease diagnosis, and human-computer interaction, highlighting the potential of the micropatterned hybrid sheet to advance sensor technology.