Researchers of Bejing University, China, have developed a new facile method to fabricate a superhydrophobic surface with hierarchical nano- and microstructures. The surface was prepared through spin coating of a mixture of nano- and microsized calcium carbonate suspensions on a substrate, followed by modification of a low-surface-energy monolayer of stearic acid.
The key parameters of the fabrication of suitable surface morphologies were also investigated. Results showed that the optimum calcium carbonate content was 40 wt % and the self-cleaning property of the film was achieved only by the addition of 2 wt % microsized calcium carbonate powder and 38 wt % nanosized calcium carbonate powder. After modification with a self-assembled monolayer of stearic acid, the as-prepared coating showed self-cleaning properties with a water contact angle as high as 152.8° and a sliding angle of 7.8°. The complete study appeared in “Industrial & Engineering Chemistry Research“, 50 (6)/2011, pp 30893094.
More information: Hydrophilic vs Hydrophobic: The Meaning of Contact Angle.