Make the building walls always clean: A durable and anti-bioadhesive diatomaceous earth@SiO2 coating

Abstract

The mildew caused by damp on building walls is harmful to human health. It is very necessary to prevent building walls from mildew from the source to solve environmental health problems. Here, we provided a special superhydrophobic coating for the surfaces of building walls from diatomaceous earth (DE) @SiO2 by the sol–gel method, mixed with fluorosilicon (HLR-Si) resin and then sprayed on home-made walls. The resulting surface structure endowed the wall with self-cleaning properties: it had obvious anti-bioadhesion to Aspergillus and Simplicillium at 35 ℃ and above 90% humidity. The coated building walls were still waterproof after around 380 days, showing a promising application. Besides, the superhydrophobic sesame-cake-like coating was not easily destroyed after 16 peels and 300 min of stirring sand abrasion test with a speed of 250 rpm. The coating’s superhydrophobicity also remained unchanged after being misted with different inorganic salt solutions for 12 h.