Preparation and property analysis of cellulose reinforced carbon nanocomposite hydrogels

Abstract

The application of hydrogels in the field of wearable flexible sensors has been widely discussed. However, most hydrogels have certain limitations in their mechanical properties, stability and self-recovery, which greatly limits their application in flexible sensors. In this paper, carbon nanotube composite hydrogels with good stability and high tensile properties were prepared by using acrylamide (AM), cellulose nanocrystals (CNC) and multi-walled carbon nanotubes (MWCNTs) as raw materials in water/glycerol by using a one-pot method. The composite hydrogels were characterized by using scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy, and their mechanical properties, conductivity and stability were tested. The results show that the composite hydrogel has a higher elongation at break (596.02%) and a higher tensile strength (0.26 MPa) when the content of cellulose nanocrystals (CNC) is 1 wt%. This is due to the presence of hydrogen bonds and the electrical conductivity of the composite hydrogels can be improved by adding carbon nanotubes (MWCNTs). When 0.06 g carbon nanotubes (MWCNTs) were added, the conductivity of the composite hydrogel reached 0.244 S m⁻¹, showing good conductivity. In addition, the wearable flexible sensor based on the composite hydrogel had a measurement coefficient of 7.20 (400% strain), and the response time and recovery time of the hydrogel were both 150 ms, which is a short response time and can detect human movement. In addition, flexible sensors based on hydrogels can successfully detect finger and wrist movement changes and show good stability. Therefore, carbon nanotube composite hydrogels with good stability and high tensile properties have broad application prospects in the field of wearable flexible sensors.