Adding water increases effectiveness of sunscreen

Jul 08, 2014

Researchers at the University of Amsterdam have established that a common protective ingredient in sunscreens reacts differently to UV radiation than previously assumed. This leads to a decreasing efficacy and might induce harmful side effects. The Amsterdam chemists also found that adding some water can solve the issue, ultimately leading to a more effective sunscreen. They have just published their results in the Journal of Physical Chemistry Letters.

By applying state-of-the-art molecular spectroscopy researchers at the Van 't Hoff Institute of Molecular Sciences have investigated the behaviour of the octyl methoxycinnamate (OMC) molecule, a common sunscreen ingredient used for blocking UV-B radiation. They made the remarkable discovery that after the absorption of the UV-light the OMC molecule does not directly dissipate the extra energy in the form of heat. Instead, it stays in an excited 'dark' state for an extended period of time.

According to professor Wybren Jan Buma, heading the Molecular Photonics research project, this implies that the OMC molecule is prone to displaying undesirable reactivity. Indeed, chemists of the University of California at Riverside already have published research on the formation of active oxygen species in UV-radiated OMC-containing sunscreens. 'Our research provides a nice explanation for this phenomenon', says Buma Just add The researchers expect that reducing the reactivity of OMC would lead to a better UV-blocking capacity. In their article in the Journal of Physical Chemistry Letters, published online last week, the UvA researchers present a way to do just that.

PhD student Eric Tan, who performed the research together with laser engineer Michiel Hilbers, discovered that the presence of water molecules facilitates the OMC molecule in returning instantly to its stable electronic ground state. This means that adding water to the sunscreen formulation should significantly add to its performance. For this the researchers propose to employ reverse micelles that make it possible to 'embed' nanodroplets of polar water in the predominantly nonpolar mixture.

Explore further: New clues to skin cancer development show sunscreen is not enough

More information: Eric M.M. Tan, Michiel Hilbers, Wybren Jan Buma: "Excited state dynamics of isolated and microsolvated cinnamate-based UV-B sunscreens," J. Phys. Chem. Lett., 2014, 5, pp 2464–2468 DOI: 10.1021/jz501140b

add to favorites email to friend print save as pdf

Related Stories

Barrier reef corals deliver world first for sunscreen

Aug 02, 2013

CSIRO, in partnership with skincare company Larissa Bright Australia, has created the world's first UVA/UVB sunscreen filters which mimic the natural sun protection used by corals on the Great Barrier Reef.

Study examines UV nail salon lamps, risk of skin cancer

Apr 30, 2014

Using higher-wattage ultra violet (UV) lamps at nail salons to dry and cure polish was associated with more UV-A radiation being emitted, but the brief exposure after a manicure would require multiple visits for potential ...

Recommended for you

Electronic switches on the molecular scale

Nov 25, 2014

A molecular electronic switch is a junction created from individual molecules that can alternate between two or more stable states, making the switch act as a conductor or an insulator. These switches show ...

Mimicking photosynthesis with man-made leaves

Nov 25, 2014

Scientists have long been trying to emulate the way in which plants harvest energy from the sun through photosynthesis. Plants are able to absorb photons from even weak sunlight using light antennae made ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.