Transparent superhydrophobic coating application to the interlocking clay block for the microbial growth mitigation

Interlocking clay block is of widespread use in many countries due to its less labor-intensive design. The block comprises of considerable amount of pore structures; therefore water can easily penetrate into it causing deterioration by natural weathering as well as the growth of microbes on its surface. In this present work, a transparent, superhydrophobic coating was applied onto the block's surface to prevent water absorption. The coating which is a poly(methyl hydrogensiloxane) base containing fumed SiO₂ nanoparticle was designed to possess surface topographic feature similar to that of the lotus leaf. After coating the block with the superhydrophobic compound, its water absorption decreased from 11.5 to 4.8% and porosity substantially decreased from 22.5 to 9.2%, while bulk and apparent densities did not change. Accelerated weathering test revealed that the coating had good stability. The coated samples exhibited growth inhibition of algae. (paper)