Stretchable Triboelectric Self‐Powered Sweat Sensor Fabricated from Self‐Healing Nanocellulose Hydrogels

Abstract

Though visualizing perspiration constituents is crucial for physiological evaluation, inadequate material healing and unreliable power supply methods restrict its applications. Herein, a fully flexible self-powered sweat sensor is fabricated from a cellulose-based conductive hydrogel to address these issues. The hydrogel electrode is composed of a cellulose nanocomposite polymerized in situ with polyaniline and cross-linked with polyvinyl alcohol/ borax. The cellulose nanocomposites furnish the sweat sensor with tensile and electrical self-healing efficiencies exceeding 95% within 10 s, a stretchability of 1530%, and conductivity of 0.6 S m −1 . The sweat sensor quantitatively analyzes Na + , K + , and Ca 2+ contents in perspiration, to sensitivities of 0.039, 0.082, and 0.069 mmol -1 , respectively, in real time via triboelectric effect and wirelessly transmits the results to a user interface. This fabricated sweat sensor with high flexibility, stability, and analytical sensitivity and selectivity provides new opportunities for self-powered health monitoring.

Isolation and Characterization of Cellulose Nanocrystals from Date Palm Waste

“… 6 Additionally, CNC’s large specific surface area (hundreds of m 2 /g), 7 high elasticity modulus (approximately 150 GPa), 8 ultralightweight (1.6 g/cm 3 ), 9 biodegradability, 10 and biocompatibility 11 are the main factors that encourage its use as a reinforcement agent in composite manufacturing. Additionally, CNC can be used to prepare barrier films, 12 shape-memory polymers, 13 bionanocomposites, 14 drug-delivery materials, 15 photonic crystals, 16 biomedical devices, 17 filaments, 18 aerogels, 19 hydrogels, 20 fuel cells, 21 and three-dimensional (3D) printing 22 as well as for wastewater treatment 23 and producing agricultural products, 24 adsorbents, 25 and materials for cultural heritage. 26 The surface chemistry of cellulose derivates can further be modified to use in many other applications.…”

Biocompatible Conductive Hydrogels: Applications in the Field of Biomedicine

“…In medical and daily health monitoring, visualization of sweat composition is critical for physiological assessment, but the material's insufficient healing ability and unreliable power supply methods limit its application. Qin et al [140] fabricated a self-powered sweat sensor using the developed cellulose-based CHs to address these issues (Figure 3b). Among them, the CHs electrodes consist of cellulose nanocomposites based on PVA and PANI.…”

A flexible, robust cellulose/phytic acid/polyaniline hydrogel for all-in-one supercapacitors and strain sensors

“…Cellulose is one of the most widely sourced natural polymers, with excellent biocompatibility, degradability, and no biological toxicity, 9 which can serve as conductive hydrogels and replace synthetic polymers in line with the principles of green chemistry. 10,11 A variety of conductive cellulose hydrogels have so far been realized with conducting polymers, 12 carbon-based nanomaterials, 13 ionic liquids, 14 and inorganic salts 15 as conductive media. Benefiting from the inherent flexibility, mechanical recoverability, ionic conductivity, biocompatibility, and biodegradability, conductive cellulose hydrogels have presented attractive merits for use in the field of energy storage, sensing and so forth.…”