Enhancing adhesive performance of polyvinyl alcohol with sub-nanoscale polyoxotungstate clusters under extreme conditions

Innovative advancements in the development of high-performance, eco-friendly adhesives are critical for meeting the demands of diverse applications in various industries. This study reports a significant leap in adhesive technology by enhancing the interfacial toughness and versatility of polyvinyl alcohol (PVA) through complexation with 1-nm Keggin-type polyoxotungstate clusters (POTs) carrying specific negative charges. The POT-PVA nanocomposites exhibit superior adhesion to hydrophilic surfaces, attributed to their high crosslinking densities and exceptional fracture energies surpassing 6.23 kJ·m⁻². These adhesives, endowed with high flexibility and a wealth of surface hydroxyl groups, are uniquely suited for application on a wide array of substrates including glass, steel, aluminum, and beyond, demonstrating their broad applicability. Specifically, the reduction in PVA crystallinity due to the chaotropic effect of POTs, which significantly enhances polymer chain dynamics. This enhancement confers robust adhesive properties at extreme temperatures, from the cryogenic −196 °C to the high-temperature threshold of 100 °C. By capitalizing on the chaotropic effects of charged POTs, the study achieves a notable enhancement in the adhesive capabilities of the POT-PVA nanocomposites, paving the way for the development of for eco-friendly and cost-effective adhesives engineered to withstand extreme conditions.