A general approach for superhydrophobic coating with strong adhesion strength

Superhydrophobic coatings with strong adhesion strength, high chemical stability and good self-cleaning function are fabricated by a new colloid assembly method. This method involves the utilizing of dual-sized particles to achieve a micro/nano structure, and an acidic silica sol to bond the particles with substrates. The resulting coating has a contact angle higher than 160 degrees and a hysteresis angle of 2 degrees, showing excellent superhydrophobic properties. The adhesion strength of the coating is proved to be strong according to the ASTM international standard. The smoothing effect of the bonders can be completely overcome by adjusting the ratios and sizes of the dual-sized silica particles. Because of its flexibility and simplicity, the present colloid assembly method may be suitable for large-scale coating.