There is welcome news for people who found it inconvenient to press smartphone screens because of long nails. U.S. researchers are developing a clear nail polish that, when applied to the nail, helps operate touchscreens.
A research team led by Joshua Lawrence of Centenary College in the United States presented related findings at the American Chemical Society (ACS) spring meeting held from the 22nd to the 26th.
Most smartphone and tablet screens use capacitive touchscreens. A very weak electric field forms on the screen surface, and when a conductive object like a finger or a water droplet touches it, the screen's electric field changes slightly. The device detects this change and recognizes it as a touch.
In contrast, objects that are poor conductors, like nails, do not create such changes, so the screen does not respond. In practice, people who keep long nails often touch the screen with the side of a finger or the fingerprint area instead of the fingertip.
The researchers found a way to increase electrical responsiveness by adding specific substances to a clear polish applied to the nail surface. There have been attempts to add carbon nanotubes or metal particles to nail products before, but they posed an inhalation risk during manufacturing and turned the polish black or metallic, making it difficult to produce a clear product.
After testing combinations of 13 commercially available clear nail polishes and more than 50 additives one by one, they found that mixing taurine-based substances and ethanolamine into the polish allowed users to operate smartphone screens with their nails. Taurine is an organic compound widely known as a health supplement ingredient, and ethanolamine is a simple organic molecule.
The researchers said the newly developed product may work differently from existing conductive nail products. Instead of metal or carbon particles directly conducting electricity, it may operate by charges moving during acid–base reactions, which the screen then detects.
Once complete, the technology can be applied over existing nail art or directly on bare nails. The team also expects it could help people whose screen touches do not register well because of calluses on their fingertips. In other words, it could become an assistive technology that improves everyday convenience beyond simple cosmetics.
However, challenges remain. Ethanolamine has slight toxicity and evaporates quickly after being taken out of the bottle, so the effect lasts only a few hours. Taurine is non-toxic, but it makes the polish somewhat less transparent.
The researchers noted, "It will take more time before it is released as an actual product. Lowering toxicity further and extending its duration remain tasks," adding, "We are continuing to screen compounds and test new combinations to find the optimal blend."