Scientists have been looking to create water repellent and self-cleaning surfaces for years with a varying range of success. One of the key issues with self-cleaning surfaces is their inability to retain their properties post damages including abrasion, scratches, oil exposure among other things. Scientists have created a paint not only provides ultimate self-cleaning surfaces, but also continues to retain those abilities even in cases of damaging effects.
“Our paint worked extremely well for a variety of surfaces in tough conditions which were designed to simulate the wear and tear of materials in the real-world”, says First author Yao Lu of UCL Chemistry. The paint has been made from coated titanium dioxide nanoparticles and can be applied to a range of surfaces to provide them with self-cleaning abilities.
The paint, composed of titanium dioxide (TiO2) nanoparticles, is delivered as a suspension in ethanol containing the chemical perfluorooctyltriethoxysilane. Once the coating is applied on any surface, the ethanol needs to be allowed to evaporate for 180 seconds before it is ready for use. Depending on the surface on which it is applied, the coating can be sprayed, dipped, or painted onto a surface.
Professor Claire Carmalt, Professor of Inorganic Chemistry at UCL Chemistry, and co-author of the paper said that the biggest challenge for the widespread application of self-cleaning surfaces is finding a way to make them tough enough to withstand everyday damage. She adds that surfaces tend to be mechanically weak and so rub off easily.
“By pairing our paint with different adhesives, we’ve shown it is possible to make a robust self-cleaning surface. We used materials that are readily available so our methods can be scaled-up for industrial applications.”
The self-cleaning properties of the paint are also excellent. To demonstrate this, scientists poured water over spray coated filter paper contaminated with artificial dust. The water completely removed the dirt from the spray-coated filter paper.
Further, scientists extended the test by inducing several types of damage including finger-wiping to contaminate surfaces with oils, knife scratches, and multiple abrasion cycles with sandpaper and still the self-cleaning properties were retained.
“Our work aims to characterise new materials at a very small scale so we can see how best to use them to improve our daily lives”, concluded Professor Ivan Parkin, Professor of Chemistry and Head of UCL Chemistry, and corresponding author of the paper.
“The new paint fits into a broader portfolio of surfaces we are developing for different purposes, including antimicrobial coatings to combat hospital acquired infections, and we hope its discovery advances the widespread adoption of self-cleaning surfaces.”
The study, published in Science, is a collaborative effort of researchers from UCL, Imperial College London and Dalian University of Technology (China).