Cellulose–Phytic Acid Hydrogel with Synergistic Mechanical–Electrical Properties and Antifreezing Stability for Information Encryption

Cellulose-based hydrogels, owing to their softness, biocompatibility, and ionic conductivity, hold promise for applications in wearable sensing and human–machine interfaces. Herein, we present an effective strategy for synthesizing the PAAP-CMCs-PA hydrogel by incorporating carboxymethyl cellulose (CMC) and phytic acid (PA), with an optimized balance between mechanical and conductive properties. Strong electrostatic interactions and multiple hydrogen bonds are established within the polymer network, thereby reinforcing structural stability and endowing the hydrogel with excellent integrated properties. As a result, the PAAP-CMCs-0.2 PA hydrogel exhibits high ionic conductivity (7.8 S/m), considerable tensile strength (0.68 MPa), substantial stretchability (1473%), and robust adhesion (10.38 kPa) on diverse substrates. In addition, the hydrogel demonstrates remarkable antifreezing performance at low temperatures and reasonable antibacterial activity. These multifunctional properties endow the hydrogel with stable signal-detection capability for subtle motions, thereby enabling Morse code information transmission, indicating an effective design strategy for flexible sensors in harsh cold conditions.