Investigating the use of nanoclay for superhydrophobic coatings
Organically modified layered silicate nanoclay particles were dispersed into a sol-gel silica matrix to obtain a formulation for generating a superhydrophobic coating.
Dimethyldiethoxy silane, tetraethoxysilane and hexamethyldisilazane were used as precursors. Commercially available organically modified montmorillonite clay, “Cloisite 25A” was used as the source of nanoclay. The loading of “Cloisite” into the hybrid silica sol was varied and coatings were generated by dip coating technique on soda lime glass substrates. Heat treatment was carried out in air at 250 °C for 2 h. In some cases, spray coating was also employed and pigmented coatings were deposited on aluminum substrates and cured using the same conditions as employed for coatings generated using dip coating. Coatings were characterised for their transmittance, haze, thickness, water contact angles, surface morphology using scanning electron microscopy, atomic force microscopy and resistance to weathering.
Exploring a pathway towards practical applications
The present investigation explored for the first time, a pathway towards practical applications of nanoclay dispersion in silica matrix for generation of environmentally friendly superhydrophobic coatings in a cost effective manner. Water contact angles as high as 170 ± 2° could be generated using optimised compositions and heat treatment conditions of sol and nanoclay fillers.
The study is published in: Surface and Coatings Technology, Volume 264, 25 February 2015, Pages 121-126.
