Supervisors: Dr. Arnout Imhof and Dr. Krassimir Velikov
Promotor: prof. dr. Alfons van Blaaderen
Funding: STW
Employed: 1 September 2015 – 31 August 2019

Colloidal UV absorbers

In this project, we are investigating and designing colloidal particles with various interesting and useful properties under ultraviolet (UV) light.

One essential issue within consumer products is protection against UV radiation. The main challenges faced within UV protective coatings, in particular, are enhancing protection over a broader spectrum of UV radiation and maintaining photostability [1, 2]. There is therefore a necessity for a flexible technology which allows the delivery of multiple sunscreens, with the possibility of pairing with antioxidants for photostabilisation. Therefore, in one line of research we are investigating biobased colloidal nanoparticles as vehicles for the delivery of multiple sunscreens and antioxidants (Figure 1). We are specifically interested in designing these vehicles from water-insoluble polysaccharides and proteins (e.g. ethyl cellulose, zein), which are relatively unexplored when compared with their soluble analogues [3].

In a second line of research we are developing anisotropic silica-based colloidal particles containing materials that demonstrate interesting properties under UV light. However, the synthesis and development of such structures is challenging. We hope to realise entirely new structures via solution-based chemistry.

Figure 1: An illustration taken from reference 3 nicely outlining the concept behind our first line of research. On the left, an absorbance spectrum of a biobased nanoparticle dispersion shows broadband UV protection. On the right, a TEM image of the nanoparticles. Scale bar 500 nm.

[1] K Morabito et al., Int J Cosmet Sci, 33, 385-390 (2011)
[2] Saltzman et al., Nat. Mater, 14, 1278-1285 (2015)
[3] D. R. Hayden et al., ACS Appl. Mater. Interfaces, 8, 32655-32660 (2016)