THE USE OF HYDROPHOBIZED PERLITE AS THE BASE LAYER OF SUPERHYDROPHOBIC COATINGS

Abstract

The development of superhydrophobic materials technology is limited due to low mechanical stability of coatings, complexity of scaling and relatively high cost. One possible way to solve this problem is to use technologies that are used for conventional coatings, such as creating a surface texture by using functionalized fillers. The article considers an example of a method of obtaining such coatings by mechanical grinding of foamed perlite. The geometry of crushed perlite particles, the shape and particle size distribution of their fragments formed during grinding were characterized in the work. An effective surface modifier has been selected to provide superhydrophobic properties and the possibility of forming coatings based on these materials has been established. The structure and water-repellent properties were also characterized. As a result, it is shown that the use of crushed material with hollow particles on the example of expanded perlite after chemical surface treatment is a possible way to obtain coatings with high water-repellent properties. The created systems have a stochastic structure and relatively high values of the wetting angle – up to 140°. The properties of crushed perlite particles were determined – the average particle size is 15 μm, the shape of the fragment and the possibility of modification using siloxane processing agents. In particular, it has been shown that the use of polymethylhydrosiloxane for modification provides its chemical binding on the surface of perlite. The layer of treated particles has a marginal wetting angle of up to 150° and a rolling angle of less than 4°. These particles were successfully bonded with a styrene-acrylic polymer matrix, which led to the formation of coatings with high hydrophobicity at filler levels above 50 wt. %.