Robust\nWaterborne Superhydrophobic Coatings with Reinforced\nComposite Interfaces

Abstract

Waterborne superhydrophobic coatings\nhave attracted tremendous\nattention recently, but their practical applications are severely\nlimited by hydrophobic instability and poor mechanical durability.\nHerein, a novel robust waterborne PTFE-CP&MgO-AOP superhydrophobic\ncoating was successfully fabricated by reinforcing composite interfaces.\nCombined with the self-polymerization of dopamine and the in situ\ngrown MgO, CNTs-polydopamine&MgO (CP&MgO) particles with improved\ninterfacial compatibility were obtained. Through the cross-linking\nand hydrogen bonding interactions, phosphate networks (CP&MgO-AOP)\nwith the aluminum orthophosphate (AOP) binder were formed during dehydration\npolymerization. The phosphate networks not only enhanced the interfacial\ninteraction among CP&MgO to form coral-like structures but also\nstrengthened the interfacial binding force between the waterborne\npolytetrafluoroethylene (PTFE) coating and the substrate. With the\nenhanced composite interfacial strength, the waterborne PTFE-CP&MgO-AOP\ncoating exhibited excellent wear-resistance, which can withstand more\nthan 1.27 × 10⁵ abrasion cycles. Moreover, the chemical\nbonding between the functional groups of phosphate networks and metal\nsubstrate improved the adhesion strength from grade 5 to 1. Furthermore,\nthe prepared coating surface with the reticular/coral-like composite\nstructures can lock the stable gas layer to maintain excellent hydrophobic\nstability, even under the conditions of strong acidic/alkaline, high-temperature,\nxenon lamp irradiation, and mechanical wear. Thus, this study is expected\nto open new insights into interfacial enhancement of robust waterborne\nsuperhydrophobic coatings.