Spiropyran-functionalized photochromic nylon webbings for long-term ultraviolet light sensing

Peng Zhang, Osgar John Ohanian, Maurizio Porfiri

Research output: Contribution to journalArticlepeer-review


Webbing structures are extensively employed in engineering systems as load-bearing components. In a field setting, webbings are frequently subject to extended ultraviolet (UV) light irradiation, which can affect their integrity and reduce their mechanical strength. Despite technological advancements in structural health monitoring, long-term UV sensing techniques for webbings remain under-developed. To fill this gap, we propose a photochromic nylon webbing that demonstrates color variation in response to extended UV exposure. The webbing offers a rich, yet controlled, color variation over multiple time scales that is conducive to UV sensing. A mathematical model grounded in photochemistry is developed to interpret experimental observations, unveiling the photochromic phenomenon as a multi-step, multi-timescale photochemical process involving several chemical species. The model captures the evolution of the coexisting species through a system of nonlinear, coupled ordinary differential equations, offering the basis for the inference of the webbing's color. The proposed photochromic webbing and the photochemistry-based mathematical model could inform future designs of UV-sensitive structures that maintain sensitivity under weeks of continuous sunlight UV exposure.

Original languageEnglish (US)
Article number064504
JournalJournal of Applied Physics
Issue number6
StatePublished - Aug 14 2022

ASJC Scopus subject areas

  • General Physics and Astronomy


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