Superhydrophobic self-cleaning surfaces and slippery lubricated ones effect upon inorganic scaling.

Several industrial processes involving a medium rich in carbonates and sulfates suffer from inorganic scaling onto its facilities, which can result in severe damage to equipment, production and the environment. Nucleation and growth inhibitors are often used to minimize or prevent scaling. Nonetheless, such procedures require constant refill of inhibitor compounds, which means higher costs and higher environment impact. An alternative method to avoid scaling would be prevent the salts from adhering to the surface, and, for that, surface modifications aiming to create low adhesion and low wettability could be employed. Barthlott and Neinhuis1 unveiled the Lotus Effect, by which the path to superhydrophobic self-cleaning surfaces development was open. Wong et al.2 stepped forward mimicking Nepenthes pitcher plant slippery lubricated surface, which presented omniphobic behavior. Both surface phenomena seem to be eligible to act like scaling preventers avoiding adhesion of precipitates, thus, they were tested at this work. Polyaniline was electropolymerized by galvanostatic method onto stainless steel, leading to hierarchical structures which were chemically modified with perfluorinated thiol to lower their surface energy. Then, the surfaces were characterized as superhydrophobic self-cleaning by contact angles measurements. Slippery surfaces were built by a lubrication of the abovementioned superhydrophobic surfaces with perfluorinated oil. Both surfaces were assessed after immersion at controlled inorganic scaling environment. Results showed that superhydrophobic self-cleaning surfaces not only fail to stand its properties as also increases the inorganic scaling formation, while lubricated slippery one superbly prevents it.