Fabrication of Polyacrylamide Hydrogels with Improved Mechanical Performance via Bamboo Macro/Nano-Cellulose Fibers

Ion-conductive polyacrylamide (PAM) hydrogels hold great potential in flexible sensing applications. The pure PAM hydrogels exhibit low mechanical strength and cyclic performance. Hierarchical multi-scale bamboo macro-cellulose fiber and nano-cellulose fiber are developed to modify PAM ion-conductive hydrogels, using a ZnCl2/AlCl3 binary solvent. SEM results show that the addition of bamboo cellulose to the PAM hydrogel reduces the pore structure, but no agglomeration is observed. FTIR results show that hydrogen bonding interactions occur among bamboo fibers, water, and the PAM matrix. The hydrogels modified by bamboo fibers retain flexibility, transparency, and adhesivity. The ionic conductivity of modified hydrogels is in the range of 32–46 mS/cm. The tensile strength of hydrogels improves moderately from 0.1 MPa to 0.15 MPa with elongation over 1600%. The bamboo nano-cellulose fiber shows a higher enhancement effect on mechanical strength. The hydrogels possess good cyclic tensile and compressive performance in 20 consecutive cyclic tests. This bamboo multi-scale fiber modification strategy provides a simple and sustainable method for property improvement of flexible conductive hydrogels.