Interfacial Phenomena on the Inorganic Scaling Prevention

Superhydrophobic and lubricated slippery surfaces were tested under high salinity inorganic scaling medium and had their antifouling capacity assessed by optical and electron microscopy. The superhydrophobic surfaces were build up with hierarchically rough electropolymerized polyaniline onto stainless steel substrates and functionalized with low-polarizability thiols. Subsequently, these materials were lubricated with perfluorinated oil to obtain slippery surfaces. Regardless of the large amount of inorganic scale found onto superhydrophobic surfaces after the scaling test, the slippery ones showed to be very efficient as fouling preventers. From crystal quartz microbalance experiments, the wetting regime of the superhydrophobic surfaces was evaluated and shows that the Cassie-Baxter effect was not lost during the entire scaling test. The interfaces energies of the systems were assessed with contact angle experiments and showed that the scaling increases because the interfacial free energy is minimized. These results lead to a better understanding of how superhydrophobic surfaces could induce inorganic scaling instead of preventing it.