An Ultra-Strength, Low-Temperature-Curing Adhesive Enabled by a Polyphenol-Enhanced Phase-Separation Network

To address harmful volatile emissions from formaldehyde-based adhesives and the high energy consumption of thermosetting adhesive curing, this study proposes a water-based, environmentally friendly adhesive inspired by natural liquid-liquid phase separation. A synergistic combination of silicone-acrylic (SA) emulsion, cationic polyamidoamine-epichlorohydrin (PAE), and plant-derived tannic acid (TA) was used to construct a phase-separated cross-linked network through multiple dynamic interactions. This bioinspired design enables low-temperature rapid curing, eliminating traditional high-temperature processes. The adhesive exhibits outstanding performance: cold-pressed plywood achieves a wet shear strength of 2.58 MPa, retaining 1.24 MPa after 72 h of continuous boiling, demonstrating reliable durability in extreme humid and hot environments and helping to reduce material waste and degradation-related losses. It also exhibits broad substrate applicability with bond strengths of 23.5 MPa for wood and 12.95 MPa for metals. Moreover, it can be processed into self-supporting films with high toughness (elongation of >350%) and high strength (tensile strength of >16.5 MPa). This work presents a strategy for high-performance, low-environmental-impact adhesives, which is promising for green composite manufacturing and clean production.