The Use of Melanin to Produce Structural Colors

Speaker 

Ali Dhinojwala, University of Akron

Abstract 

Structural colors are ubiquitous in nature and is an alternate process to produce synthetic pigments that have a higher UV stability than dye pigments, a potential to change colors by simply using a stimuli, and offer organic non-toxic color options for food and cosmetic applications. Birds use a combination of melanin, keratin, and air to produce structural colors. Melanin is particularly interesting because it is inherently black, therefore, have a broad absorption spectra in the visible region which results in high saturation and contrast. In my presentation, I will discuss how melanin in bird feathers lead to structural colors. This unique knowledge has led us to design synthetic melanin and self assembly processes to generate colors in the visible spectrum. Controlling the separation between melanin particles is the key to produce different visible colors. We have achieved this by using core-shell particles with melanin core and silica shells. I will discuss some of the new physics that is emerging from studying the self assembly process and open questions in this field.