Cellulose reinforced carbon nanocomposite hydrogels for wearable sensors

he application of hydrogel in the field of wearable flexible sensors has been widely discussed. However, most hydrogels have some defects in mechanics, stability, and self-recovery, which greatly limit their application in flexible sensors. In this paper, carbon nanotube composite hydrogels with good stability and high stretchability were prepared by the one-pot method in water/glycerol binary solvent using acrylamide (AM), cellulose nanocrystals (CNC) and multi-walled carbon nanotubes (MWCNTs) as raw materials. The composite hydrogels were characterized by scanning electron microscopy and Fourier transform infrared, and their mechanics, conductivity, and stability were tested. The results show that when the content of cellulose nanocrystals (CNC) is 1 wt%, the composite hydrogel has a higher elongation at break (650.96%) and a higher tensile strength (0.26 MPa). This is due to the presence of hydrogen bonds, and the conductivity of the composite hydrogel can be improved with the addition of carbon nanotubes (MWCNTs). When 0.04 g of carbon nanotubes (MWCNTs) were added, the conductivity of the composite hydrogel reached 0.244 S/m, showing good conductivity. In addition, the wearable flexible sensor based on the composite hydrogel has a measurement factor of 7.33 (strain 400%), which can detect human movement. Therefore, carbon nanotube composite hydrogels with good stability and high stretchability have broad application prospects in the field of wearable flexible sensors.