Environmentally friendly solvent- and water-based coatings for mitigation of crystallization fouling

The surface properties of solvent-based (SB) and water-based (WB) coatings and their impact on fouling during convective heat transfer of CaSO₄ solutions were investigated. Experiments demonstrated that the SB coatings had generally better non-adhesive characteristics, especially at higher values of the electron donor component since the deposits could easily be washed away. For the SB coatings, a longer induction period compared to those of untreated surfaces was observed and a significant reduction of the fouling rate could be achieved. Further analysis of surfaces revealed that SB coatings enhanced the acid-base repulsive force and thus reduced the deposit/solid adhesion energy. For the WB coatings, the Liftshitz-van der Waals attractive force plays a decisive role in the adhesion process due to the higher apolar component of the surface energy.