Self-Cleaning Coating Withstands Abuse

FRIDAY, MARCH 13, 2015


Like the famous watches that took a licking and kept on ticking, a tough new paint maintains its self-cleaning properties after assault by oil, knives and sandpaper, its developers say.

The "robust" coating could be used in a wide range of applications, including glass, steel, paper and cloth, announced researchers from the University College London, Imperial College London, and Dalian University of Technology (China).

Details of the research have been published in the journal Science.

The Challenge

“The biggest challenge for the widespread application of self-cleaning surfaces is finding a way to make them tough enough to withstand everyday damage,” co-author Clair Carmalt, a professor of inorganic chemistry at UCL, said in a statement.

“The surfaces tend to be mechanically weak and so rub off easily, but 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,” she said.

Research Details

The new coating—made from coated titanium dioxide nanoparticles combined with adhesives—creates a more resilient surface that resists everyday wear and tear, the team says.

Yao Lu

The coated surface self-cleans as water forms marble-shaped droplets that roll over the surface, picking up dirt along the way.

Different coating methods were used to create the water-repellent surfaces, depending on the material.

For example, a spray gun was used to coat glass and steel, cotton wool was dip-coated, and and a syringe was used to apply the paint on paper, according to the team.

All the materials became waterproof and self-cleaning as water droplets of different sizes were seen bouncing instead of wetting the surface, removing the dirt applied by the researchers, the team adds.

“Being waterproof allows materials to self-clean as water forms marble-shaped droplets that roll over the surface, acting like miniature vacuum cleaners picking up dirt, viruses and bacteria along the way,” said author Yao Lu, UCL Chemistry.

Withstanding Damage

The coatings' self-cleaning properties were maintained even after damage was inflicted on the surfaces. The team reportedly finger-wiped, knife-scratched and sandpaper-scuffed the surface for 40 abrasion cycles.

Then, the team filmed the experiments to show the behavior of the treated surfaces against controls.

Self-cleaning Paint
Oli Usher

Treated cotton wool remains pristine, uncontaminated by the dyed water droplets.

The videos include a treated cotton-wool being dipped into blue-colored water and emerging pristine white with no trace of contamination, and treated paper remaining dry and clean after being exposed to dirt and water, according to the research team.

Research Goals

“Our work aims to characterize new materials at a very small scale so we can see how best to use them to improve our daily lives,” said Ivan Parkin, the head of the UCL Chemistry department.

“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.”

   

Tagged categories: Asia Pacific; Coating chemistry; Coating Materials; Coatings manufacturers; EMEA (Europe, Middle East and Africa); Glass; Research; Self-cleaning coatings; Steel; Substrates

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