Design of a Hot-Melt Adhesive with Microphase-Separated Architecture Enabled by Hydrogen-Bond Engineering for Robust and Reversible Adhesion

The interfacial adhesion of linear polymers is often limited by the balance between cohesion and interfacial adhesion strength. Here, a novel hot-melt adhesive capable of rapid bonding, recyclability and reusability was developed by simple mixingthioctic acid (TA) and polyurea (PU) in the presence of ethanol. By evaporating the solvent, a polymer hydrogen-bonded network with a microphase-separated structure is constructed in situ, thereby significantly enhancing the interfacial adhesion strength. Owing to the dynamic polymerization mode and reversible cross-linking characteristic of PTA, the PTA/PU system exhibits reversible cyclic adhesion and recovery properties. Through hydrogen-bond engineering, the premature dissociation of dynamic bonds is regulated, and the thermal stability of PTA/PU is notably improved. The adhesive demonstrates a shear strength of 14 MPa on metallic substrates such as stainless steel and maintains stable cyclic adhesion for over 15 cycles. Furthermore, the hydrophobic PTA/PU network can induce interfacial water exchange during adhesion, enabling strong adhesive performance even in underwater environments. This study shows that by designing hydrogen bonds between linear polymer molecules, robust adhesion can be achieved through simple assembly, further highlighting the critical role of cohesive force regulation in the adhesion process.