Conductive cellulose nanofibrils-reinforced hydrogels with synergetic strength, toughness, self-adhesion, flexibility and adjustable strain responsiveness

• Published in: Carbohydrate polymers Vol. 250; p. 117010
• Main Authors: Lu, Jinshun, Han, Xiao, Dai, Lin, Li, Chenyu, Wang, Jingfeng, Zhong, Yongda, Yu, Faxin, Si, Chuanling
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 15.12.2020
• Subjects: cellulose; cellulose nanofibers; Cellulose nanofibrils; electrical conductivity; humans; Hydrogel; hydrogels; hydrogen; mechanical stress; Sensor; storage modulus; Strain responsiveness; Tannic acid; tensile strength; Tannic acid; Strain responsiveness; Cellulose nanofibrils; Hydrogel; Sensor
• ISSN: 0144-8617; 1879-1344; 1879-1344
• DOI: 10.1016/j.carbpol.2020.117010

•A flexible cellulose composite with dual network including conductivity was prepared.•The hydrogel displays high mechanical strength, and strong toughness and tensile strength.•The hydrogel displays excellent self-adhesion and adjustable strain responsiveness.•Human movements can be monitored by the hydrogel strain sensor. The development of biomass-based hydrogel conductive devices is a promising but challenging subject. Here, cellulose was used to develop a strong, tough, and self-adhesive conductive hydrogel by constructing a synergistic covalent cross-link network and multiple physical interactions. Tannic acid-coated cellulose nanofibrils (TA@CNFs), poly(acrylamide), and ferric ions (Fe3+) were introduced in a composite network by coordination and hydrogen bonds. The strategy of interpenetrating network endowed this hydrogel with high mechanical strength (storage modulus over 14 K Pa), and strong toughness and tensile strength (fracture stress up to 108 K Pa). Chelated Fe3+ by metal coordination as inorganic conductive phase leads to good electrical conductivity (conductivity up to 3.12 S m−1). The obtained hydrogel also exhibited fine flexibility, extensive self-adhesion, and adjustable strain responsiveness for monitoring human joint movements. This work provided a new approach to design conductive hydrogels, and also can expand the application of cellulose-reinforced materials in the sensor field.