On-demand Peelable UV-curable Adhesives with Superior Bonding Strength: Rational Molecular Engineering of Cohesion-adhesion Synergy

On-demand peelable adhesives represent a pivotal green chemistry research avenue; however, they confront a critical challenge in reconciling robust interfacial bonding strength with efficient peelability. Herein, a cohesion-adhesion synergy-guided molecular engineering strategy was developed to fabricate UV-curable adhesives with the integrated properties of superior bonding strength and hot water-triggered peelability. The adhesive was formulated with custom-synthesized difunctional polyurethane acrylate (PM1) as the crosslinker, which was blended with complementary acrylate monomers. PM1 constructed a robust yet adaptable crosslinking network to ensure high cohesive strength; its polytetrahydrofuran diol- and polyester diol-derived soft segments endowed the network with superior molecular chain mobility and stress dissipation capacity. Additionally, the incorporation and compositional optimization of polar acrylate monomers modulate the cohesive energy, surface wettability, and interfacial adhesion of the substrate, thus realizing synergistic enhancement of the cohesive and adhesive properties. Systematic experimental investigations and molecular dynamics simulations were conducted to determine the structure-property relationships governing the composition, bonding performance, and mechanical properties of UV-curable adhesives. The optimized formulation achieved high shear strength (>5 MPa, glass substrates), excellent mechanical properties (tensile strength: 12.80 MPa, elongation at break: 313.70%), and good thermal stability (5 wt% weight-loss temperature > 240 °C). Notably, the developed adhesives realize rapid, complete, and residue-free debonding within 3 min of immersion in 60 °C water, where hydration-induced disruption of adhesive-substrate contact attenuates interfacial interactions. Additionally, the peeled adhesive can be recycled repeatedly after drying while retaining its excellent interfacial bonding performance. This study provides a versatile and scalable strategy for the rational design of high-performance functional adhesives, thereby paving the way for recycling electronic products and sustainable manufacturing.