Preparation of a Modified Bamboo Fiber-Reinforced Sodium Alginate-Based Ionic Hydrogel

Modified bamboo fiber (BF), sodium alginate (SA), and NaCl were used as the raw materials. At first, the modified bamboo fiber (BF) was obtained through the surface modification of the bamboo fiber. Then, BF and SA were dissolved in a solution, and CaCl2 was used for molding. Finally, the formed hydrogel was soaked in a NaCl solution to prepare ion-conducting hydrogels with different bamboo fiber contents. The effects of BF on the mechanical properties, swelling properties, and microstructure of the composite hydrogel were investigated. The results show that when the content of modified bamboo fiber is 1.5%, the mechanical properties of the hydrogel are improved, the elongation at break reaches 340%, and the tensile strength reaches 1.58 MPa. The swelling rate of the composite hydrogel decreased to 535%. The study revealed that the conductivity of the mixed conductive hydrogels increased immediately with the concentration of the salt solution. Additionally, the conductivity of the composite conductive hydrogels showed a significant boost with the rise of the BF content under identical salt solution concentrations, which reached a conductivity value of 4.94 S/m. The optimized SA/BF conductive hydrogel was used to create a strain sensor for monitoring the pressure motion. This sensor achieved a short response time and high reproducibility for pressure. It has broad application prospects in wearable electronic devices.