A biomimetic‐structured wood‐derived carbon sponge with highly compressible and biocompatible properties for human‐motion detection

Abstract

Piezoresistive sensors, as an indispensable part of electronic and intelligent wearable devices, are often hindered by nonrenewable resources (graphene, conventional metal, or silicon). Biomass‐derived carbonaceous materials boast many advantages such as their light weight, renewability, and excellent chemical stabilization. However, a major challenge is that the strength and resilience of carbon‐based piezoresistive materials still falls short of requirements due to their random microarchitectures which cannot provide sufficiently good stress distribution. Encouraged by the excellent compressible properties and extraordinary strength of the Thalia dealbata stem, we propose a wood biomass‐derived carbon piezoresistive sensor with an artificial interconnected lamellar structure like the stem itself. By introducing a freezing‐induced assembly process, a wood‐based, completely delignified, nano‐lignocellulose material can be built into a “bridges supported lamellar” type architecture, where subsequent freeze‐drying and pyrolysis results in carbon aerogel monoliths. The resultant bioinspired carbon sponge has high compressibility and strength, of the order of two to five times higher than that of conventional metal, carbon, and organic materials. Combined with excellent biocompatible properties and chemical durability, these are useful properties for intelligent wearable devices and human‐motion detection.

Recent Progress in Development of Wearable Pressure Sensors Derived from Biological Materials

“…Biocarbon materials derived from plant materials that have fibrous, [ 104 ] tubular, [ 23 ] or hollow [ 105 ] structure have been widely applied in wearable piezoresistive pressure sensor. Sunflower pollen (SFP) has been used as hollow microcapsules as the active component to fabricate a highly sensitive pressure sensor.…”

“…Cotton is composed of 90–95% cellulose, and is a useful raw material for fabrication of porous carbon. Pyrolysis of fluffy cotton yields a sponge‐like carbon cotton (CC) (Figure 8j), [ 104b ] which has moderate electrical conductivity (11 S m −1 ) as a result of its interconnected carbon fiber networks. CC is highly porous, so the flexible and conductive CC/PDMS composites were fabricated by vacuum‐assisted infusion of PDMS resin into a CC scaffold (Figure 8k).…”

Wood Sponge Reinforced with Polyvinyl Alcohol for Sustainable Oil–Water Separation

“… 20 As a naturally renewable resource, wood is composed of a cellulose framework and structural supports of hemicellulose and lignin. 21 − 23 At this stage, biomass energy was widely used. Researchers reported a lignocellulosic porous carbon which had high-performance deionization (CDI), high salt adsorption capacity, and good cycle stability.…”

Magnetic‐Sensitive Crack Sensor with Ultrahigh Sensitivity at Room Temperature by Depositing Graphene Nanosheets upon a Flexible Magnetic Film

“…[ 36–39 ] Owing to high sensitivity at room temperature and flexibility, crack‐based strain sensor exhibits a promising aspect in flexible electronic and intelligent systems. [ 40–45 ] In 2014, inspired by crack‐shaped organs of spider, Zhao et al., first reported a crack‐based strain sensor with ultrahigh gauge factor of 2000 at 2% strain. [ 39 ] Although remarkable progress has been made in this field, current crack sensors are used in tactile sensing and there are few reports for crack sensor with non‐contact sensing and magnetic respond properties.…”