Water-saving toilet bowl coating gives waste the slip

Given the current worldwide push for water conservation, it's certainly ironic that people are still flushing great quantities of the stuff down their toilets. They may soon be using up to 50 percent less, however, thanks to a slippery new toilet bowl coating.

Developed by scientists at Pennsylvania State University, the liquid-entrenched smooth surface (LESS) coating is applied to standard ceramic toilet bowls in two steps.

First, a solution of molecularly-grafted polymers is sprayed on. It quickly dries, growing into a "forest" of tiny hair-like molecules – each one has a diameter about one one-millionth that of a human hair.

Although that initial treatment already leaves the inside of the bowl quite slippery, a second spray is subsequently applied, infusing a thin layer of lubricant around the hairy molecules. The whole two-step process takes less than five minutes, and the resulting coating should be good for about 500 flushes before another application of lubricant is required.

In lab tests, synthetic fecal matter slid right off the inside of a LESS-treated toilet bowl. This meant that only "a fraction" of the usual amount of water was needed in order to get that matter out of the bowl and down the drain.

As an added benefit, it was also found that the coating repelled the bacteria that can spread disease or cause unpleasant odors. With these features in mind, it is now hoped that the technology could not only make flush toilets more water-efficient, but that it could also allow waterless toilets (which are widely-used in many parts of the world) to be more hygienic and less objectionable to users.

The coating is being commercialized by spotLESS Materials, a Penn State startup. A paper on the research, which is being led by Prof. Tak-Sing Wong, was recently published in the journal Nature Sustainability.

Source: Penn State