So many strong detergents and less than ecologically friendly solvents are used in cleaning, both in industry and domestically – they may clean the stains we want removed, but we have no choice but to use them and damage the environment. However, two scientists have now come with a new, polymer-based, solution to the problem of unwanted stains, a self-cleaning coating material that can be wiped clean with just water – no elbow grease necessary!

There are a huge amount of potential applications for this research, from coatings on windows and mirrors, windshields, for anti-fog coatings that need oil resistance, additives for consumer products, bathroom cleaners, paints, sealants, to lenses and diving masks.

The research originally came about through their realization that fingerprints on a ski goggle that had an anti-fog coating were difficult to remove, which led to an exploration of how to control surface energies so that oil would detect a different surface than the water, making it possible to remove the oil without the use of soap.
The researchers, from Purdue University in Indiana, have spent the last few years developing substances that enable a surface to repel oil. The self-cleaning plastics they have developed are highly sensitive to water, which means that they can be rinsed without the use of soap or detergent. The idea of using water instead, with the potential for phasing out a lot of detergents and phosphates, could transform many industries.
John Howater and Jeffrey Youngblood presented their findings in a report to the national meeting of the American Chemical Society, explaining how they formed self-cleaning polymer coatings and anti-fogging surfaces that could be easily coated onto surfaces.

The key to their findings was understanding that one can control surface interactions to create “tunable”, or “smart”, surfaces where the things interacting with the surface “see” a different material. When this is used to create surfaces that lack an affinity for oils (oleophobic) and show a preference for water (hydrophilic), then it is possible to induce unique behavior such as self-cleaning and the separation of oil and water.

As for how they intend to develop their research in the future, Youngblood explains that they are now “trying to troubleshoot any issues with the new technology for polymeric coatings such as abrasion resistance, optimization for particular conditions, degradation, etc”. There is also the potential for using the polymers on different kinds of metals and ceramics, which would widen out their use even further.