Researchers have created a longer-lasting version of avobenzone, a common ingredient in sunscreen.

Avobenzone breaks down under sunlight, which renders it ineffective in a matter of hours.

“I have two small kids, and I’m always telling them to reapply sunscreen every hour or two because as avobenzone decomposes, it doesn’t do its job anymore,” says Marcus Weck, a professor of chemistry at New York University. “Several years ago, my research group included a graduate student, Elizabeth Kaufman, who was passionate about skin care. We started thinking, what can we do to need less of the active ingredient and reapply it less frequently?”

Weck, a materials chemist, leads a lab that creates support structures out of polymers (materials made up of repeating chains of large molecules). When attached, these polymer structures can stabilize or enhance the active ingredients in everything from drugs to environmental compounds.

Kaufman—at the time, a PhD student in Weck’s lab, and now the head of production chemistry at specialty chemical supplier BYK Wallingford—suggested that they look at the active ingredient in many sunscreens. The result of their investigation: a more stable, long-lasting avobenzone, for which Weck and Kaufman were awarded a patent this spring.

Here, Weck talks about creating a more advanced, longer-lasting sunscreen: