The polydopamine-enhanced superadhesion and fracture strength of honeycomb polyurethane porous membranes

The superhydrophobic properties of biological surfaces in nature have attracted extensive attention in scientific and industrial circles. Relative to the rolling superhydrophobic state of lotus leaves, the adhesive superhydrophobic state of geckos and Parthenocissus tricuspidata is also significant in many fields. In this work, polydopamine (PDA) with its excellent biological compatibility and strong adhesion was selected as a substance to simulate the secretion of the suckers of P. tricuspidata and it was precipitated at the surface of honeycomb polyurethane porous membranes (PUPM). The results demonstrated that the honeycomb PUPM, as prepared, displayed special super-adhesion properties similar to those of geckos and P. tricuspidata. PDA formed via self-polymerization in aqueous solution was equivalent to a double-sided adhesive, acquiring a micro-nano structure of PDA and PUPM and displaying increased surface hydrophobicity and improved adhesion properties. Even when the surface precipitation of PDA and modification with n-dodecyl mercaptan made the contact angle increase to more than 160°, the surface adhesion to water was rather strong and remained stable. The addition of the PDA adhesive can effectively change the microporous structure of PUPM, enhancing the viscosity, and facilitating an enhancement in the fracture strength.