Combination of chemical anchoring and microcapsules for durable slippery coating with anti-corrosion/scaling property

Slippery liquid-infused porous surfaces (SLIPS) with excellent anticorrosion and scale inhibition properties has attracted extensive attention, but the unstable lubricant layer significantly limit its long-term application. Herein, a robust slippery polyvinylidene fluoride (PVDF)/aluminum dihydrogen phosphate (ADP)/carboxylated carbon nanotube (C-CNTs)/microcapsules (MCs) composite coating was constructed by combining hierarchical micro-/ nanopores, chemical anchoring and microcapsules pre-storage. The homogeneous micro-/nanopores were formed owing to the phase separation of PVDF and ADP, benefiting for the storage of lubricants. The isocyanate N3390 was sprayed as binder on the substrate to enhance the interfacial bonding strength of the composite coating through the reaction of-NCO with the-OH of ADP and Al substrate,-COOH of C-CNTs. Moreover, the microcapsules containing hydroxyfluorosilicone oil in PU@SiO2 shell were synthesized via Pickering emulsion polymerization to repair the damaged lubricant layer and resist mechanical friction. Simultaneously, the prepared coating with oil film loss of 3.47 wt% can maintain its slippery performance after 6000 rpm high shear rotation, which can be ascribed to the covalent bonds generated by the reaction among the-OH groups of the hydroxyfluorosilicone oil, ADP and the-COOH of C-CNTs, resulting in the anchoring of oil molecules. This outstanding stability of lubricant layer property results in excellent anti-scaling property with the minimal calcium content (1.51 wt%) and corrosion resistance with a corrosion velocity of 2.33 x 10-5 mm/year. Therefore, the exceptional stability of this slippery composite coating offers new application possibilities in corrosion protection, marine transportation and other fields.