Inhibition of adhesion of CaCO₃ scale by polydopamine/polytetrafluoroethylene coating with stability and anticorrosion properties

Reduction of calcium carbonate (CaCO₃) scale formation on the equipment surface is essential in a wide variety of industrial fields. In this work, polydopamine/polytetrafluoroethylene (PDA/PTFE) coating prepared by the simple immersion on stainless steel (SS) surfaces was developed to suppress the CaCO₃ scale adhesion. The PDA/PTFE-coated surface showed the higher hydrophobicity (water contact angle = 133.50°) and lower surface free energy (11.92 mN/m) than the stainless-steel surface. The scale inhibiting rate of the coated surface was up to 76.8% after 12-hour immersion in the CaCO₃ solution in comparison with the untreated SS. More bubbles were observed on the PDA/PTFE-coated surfaces, and the number of bubbles increased with increasing solution temperature leading to less area for the scale adhesion. As a result, the PDA/PTFE coated surfaces have the higher antiscale ability at the higher solution temperature. Furthermore, the stripping and electrochemical corrosion tests demonstrated that the PDA/PTFE coating has the better stability and anticorrosion ability. The PDA/PTFE coating with the superior properties has potential application for the long-lasting reduction of the scale formation.