A college student has developed a prototype nail polish designed to allow fingernails to function like a touchscreen stylus, addressing challenges faced by people with long nails or calloused fingertips.
Manasi Desai, a student at Centenary College of Louisiana, worked on the project with her research supervisor Joshua Lawrence, an associate professor of chemistry at the college.
Their goal was to create a clear, nontoxic polish that enables a fingernail to interact with touchscreens in the same way as a human fingertip.
Desai said the final formulation can be applied over any manicure or directly onto bare nails, making it useful for individuals with calluses as well as those with long nails.
Touchscreens operate through capacitance, where a small electric field is disrupted by conductive materials such as human skin. This disruption is detected as a touch input.
However, nonconductive surfaces like fingernails do not register on touchscreens. This creates usability issues for individuals wearing gloves, those with dry skin, or people with calloused fingers.
The issue has previously been described as “zombie finger,” where touch input fails to register due to reduced conductivity.
Earlier attempts to create conductive nail polish involved using carbon nanotubes or metallic particles. These materials raised safety concerns and limited the range of polish colors.
Desai instead tested combinations of 13 commercially available clear nail polishes along with more than 50 additives to develop a formula that remains clear, nontoxic, and conductive.
The final formulation uses taurine, an amino acid, and ethanolamine, an organic molecule. Together, these compounds allow the polish to register touch input on a smartphone.
The mechanism relies on acid-base chemistry. According to Lawrence, the interaction between acidic and basic groups enables proton exchange at the surface of the polish, mimicking the role of ion movement in human skin.
The research was presented on March 23 at the annual meeting of the American Chemical Society.
The prototype is not yet ready for commercial use. Current formulations lose effectiveness after a short period, ranging from hours to days, while researchers aim for durability lasting days or weeks.
The least-toxic version also produces a gritty and speckled finish, which the team is working to improve.
The researchers have filed a provisional patent and continue to refine the formula to enhance performance and usability.