Related Experiment Video
Updated: Jun 24, 2026

The Evolution of Silica Nanoparticle-polyester Coatings on Surfaces Exposed to Sunlight
Published on: October 11, 2016
Photostability of UV absorber systems in sunscreens
Bernd Herzog1, Monika Wehrle, Katja Quass
1Ciba Grenzach GmbH, Grenzach-Wyhlen, Germany. bernd.hoerzog@ciba.com
Abstract:
Sunscreens are used to protect the human skin against harmful UV radiation. Today there is a trend toward higher sun protection factors (SPF) and better UVA protection. Methods for the assessment of SPF and UVA protection involve irradiation of the product, and the photostability properties of the sunscreen have an influence on its performance. Sunscreens often contain more than one UV filter. Thus it is important to understand the photostability properties of the complete system. The filter combinations used may exhibit destabilizing, stabilizing or inert interactions. For that reason, besides assessment of the properties of the single filters, photostabilities of binary filter combinations are investigated. Destabilization occurs when two UV absorbers undergo a chemical reaction after absorption of UV radiation. Stabilization may be achieved when the optical density of the system is very high, giving rise to a self-protection effect of the sunscreen film. Photounstable UV absorbers may be additionally stabilized by employing triplet quenchers. Being aware of these mechanisms and applying them for specific UV filter combinations can help in designing efficient sunscreens.
Related Concept Videos
Mutations
Chromosomal Alterations Are Large-Scale Mutations
While point mutations are changes in a single nucleotide in...
UV–Vis Spectrometers
Ultraviolet and Visible (UV–Vis) Spectroscopy: Overview
UV–Vis Spectrum
The UV–Vis spectrum of a molecule is the plot of its absorbance versus wavelength. The plot is drawn by taking molar absorptivity (ε) or log ε on the y-axis (ordinate)...
UV–Vis Spectroscopy of Conjugated Systems
One of the factors influencing λmax is the extent of conjugation in the...
Pigmentation
Melanin occurs in two primary forms: eumelanin that provides black and brown pigment and pheomelanin that provides red color. Dark-skinned individuals produce more melanin than those with pale...

