Water–Heat Dual-Activated Scalable Cellulose Film Adhesive

Despite their widespread use, synthetic adhesives raise substantial concerns regarding environmental impact, toxicity, recyclability, and volatile organic compound emissions, while their predominantly liquid nature often requires energy-intensive curing processes. Here, we report an all-cellulose film adhesive derived from renewable cellulose through a simple oxidation-reduction modification that transforms cellulose into a linear heat-softenable structure. The resulting material can be activated by either water or heat to function as an effective wood adhesive. Upon water activation, the cellulose film bonds thick wood panels into structural composites without external heating, achieving lap shear and compressive shear strengths of 3.1 and 6.5 MPa, respectively. This room-temperature, water-triggered adhesion reduces processing energy demand and is well suited for manufacturing engineered wood products. Owing to its thermoplastic behavior, the adhesive also enables heat-activated bonding of wood and paper, including thermal sealing of paper bags. This work establishes a renewable and low-emission adhesive platform, advancing sustainable alternatives to conventional petrochemical adhesives.