Effect of a Fiber Raw Material Structure on the Properties of Cellulose/Polyacrylamide Double-Network Antifreezing Conductive Hydrogels Prepared in an AlCl3/ZnCl2 Aqueous System

The trade-off between mechanical properties and ionic conductivity, together with low-temperature failure, restricts the practical application of ionically conductive hydrogels. In this work, four bleached pulp boards (eucalyptus, pine, bagasse and cotton) were dissolved in an AlCl3/ZnCl2 aqueous solution, followed by in situ polymerization of acrylamide to fabricate cellulose/polyacrylamide double-network conductive hydrogels. The cotton-based gel exhibited the best pristine tensile performance (105 kPa, 1566%) and the highest room temperature ionic conductivity (50.5 mS/cm). At −30 °C, except for pure PAM (which froze beyond the load cell limit), the other five gels remained soft (stress at 70% strain only 1.13–1.35 times that at room temperature). After freeze–thaw cycles, the tensile strengths of the bagasse and pine gels increased by 52% and 46%, respectively, whereas that of the cotton-based gel decreased by 37%. At −40 °C, the pine-based gel retained the best conductivity (0.83 mS/cm, 5.1% retention). In addition, the gels exhibited strain-dependent electrical resistance responses at the material level. The structure–property correlations indicate that the influence of the fiber source does not depend solely on the degree of polymerization, but arises from the combined effects of the aggregation state of regenerated cellulose, pore wall architecture, dynamic hydrogen bonding and water-binding capability on ion channel continuity, low-temperature ion transport and freeze–thaw-induced network reorganization. This study provides a material-level experimental basis for selecting fiber raw materials for antifreezing conductive hydrogels. Device-level performance remains to be validated.