In situ polymerization of acrylic monomers on Nano-COFs via compatibility regulation strategy towards enhancing interfacial bonding for sustainable wall painting conservation

Acrylic resin is widely used for wall painting conservation but is limited in weather resistance due to insufficient ultraviolet (UV) resistance and poor water vapor permeability. Most modification strategies employ inorganic nanoparticles; however, interfacial structural mismatch and insufficient bonding strength between phases often result in coating embrittlement. This study develops a molecular-level compatibility regulation strategy for in situ polymerization of acrylic resin monomers on nano covalent organic frameworks (COFs) to enable robust interfacial bonding through chain entanglement and hydrogen-bonding interactions. Through precise structural control of COFs, the coating achieves synergistic enhancement in mechanical strength and multifunctional performance, ensuring sustainable conservation of wall paintings. The optimized coating (P/T-30%) exhibits a fracture strain of 630%, an average UV transmittance of 37.27% (290 − 400 nm), and a water vapor transmission rate of 30.92 g/(m 2 ·24h). Under multi-factor accelerated aging tests combining UV irradiation and condensation, P/T-30% demonstrates superior overall protective performance compared to conventional protective materials. Density functional theory calculations reveal that incorporating nano-COF units substantially elevates the cohesive energy of the polymer system, thereby elucidating a key internal mechanism for enhancing weather resistance. These findings provide a pioneering approach for the application of emerging two-dimensional nanomaterials in cultural heritage conservation