Animals and plants use all kind of structures to produce vivid colours; for sexual selection; transparency for camouflaging and wavelength selective scattering for protective coatings, or thermal regulation. Although the range of material components used by nature is limited, these structures still outperform man made materials as a result of billions of years of evolution and adaption to extreme conditions. Why not learn from nature by studying its advanced materials to replicate or even optimise them?
This course will give you an overview of the various nanostructures observed in natural systems to produce all kinds of optical materials. Firstly, we will look at how colours are created in animals. Hierarchical structures in beetles, butterflies and many more species are uncovered at the origin of iridescence in nature. Photonic crystal structures in one, two and three dimensions will be introduced to gain a deep understanding of the optical phenomena at the heart of vivid appearances. This will be followed up by various examples of structural colour in plants, from leaves and flowers to fruits. While bright iridescent colours rise from periodic structures, whiteness and matt appearances can be obtained using disordered assemblies of scatterers.
Man-made paints, coatings and cosmetics often involve the use of dyes or high refractive index materials such as semiconductors. In contrast, nature is limited to the use of biopolymers to achieve outstanding optical properties. In this part of the course we will explore which biopolymers are available for making nanomaterials, the various methods used for production and limitations to these approaches.
In the last part of this course, we will take a further look at biomimicry beyond colour production, looking at transparent materials for antireflection coatings, micronscale photonic crystals for radiative cooling and further non-photonic examples.
Learning outcomes
- An overview of the various photonic effects in nature, the working principles behind them, and their various advantages and limitations;
- A deep understanding of the broad range of photonic material architectures, characterisation techniques and biomimicry structure manufacturing and processing methods;
- The development of bio-inspired photonic materials from biopolymers and its prospects in sustainable material production.
