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Department of Chemistry

 

The study of photonics structures found in nature provides a big inspiration for the fabrication of innovative optical materials.

While periodic structures give rise to a colourful appearance, due to a narrow wavelength-selective reflection, disordered ones scatter equally all the wavelengths resulting in a white colouration. In order to obtain a bright white appearance from thin materials, their internal structure has to be designed to optimise interaction with light. The optimisation of disordered structures represents an open challenge in the production of commercial white materials, where high refractive index particles are used to enhance their optical appearance. The extensive use of titania (TiO2) nanoparticles as white enhancers, for example in food, cosmetics and paper, has raised both health and environmental concerns. For this reason, environmentally friendly, biodegradable and biocompatible alternatives to the currently employed whiteners are highly desired. Nature provides an important inspiration for the study and the manufacturing of thin white materials. In particular, the brilliant whiteness shown by the Cyphochilus beetle (figure below) is obtained by means of the structural optimisation of the chitin network inside its ultra-thin scales (about 7 µm). 

In my PhD I aim to further investigate the light transport properties of the Cyphochilus beetle and extrapolate the design principle to fabricate highly scattering materials. Beetle-inspired materials could play a key role in the production of sustainable white materials. In addition, from a theoretical point of view, they could be used for gaining insight in important light transport phenomena like anomalous diffusion and Anderson localisation.

I did my undergraduate studies in Physics at the University of Calabria, Italy.

                                                                           

a) Photo of the Cyphochilus; b) image of one beetle scale taken with a confocal microscope; c) SEM image of the cross-section of a Cyphochilus scale showing the interconnected network of chitin filaments which is responsible for the white appearance of the insect; d) reflectance value associated to the Cyphochilus beetle is higher than that of the filter paper, which is about three times thicker. 

Publications

Long-Wavelength Reflecting Filters Found in the Larval Retinas of One Mantis Shrimp Family (Nannosquillidae).
KD Feller, D Wilby, G Jacucci, S Vignolini, J Mantell, TJ Wardill, TW Cronin, NW Roberts
– Current Biology
(2019)
Coherent backscattering of light by an anisotropic biological network.
G Jacucci, OD Onelli, A De Luca, J Bertolotti, R Sapienza, S Vignolini
– Interface focus
(2019)
9,
20180050
Photonic Resins: Designing Optical Appearance via Block Copolymer Self-Assembly.
D-P Song, G Jacucci, F Dundar, A Naik, H-F Fei, S Vignolini, JJ Watkins
– Macromolecules
(2018)
51,
2395
Anomalous-Diffusion-Assisted Brightness in White Cellulose Nanofibril Membranes
MS Toivonen, OD Onelli, G Jacucci, V Lovikka, OJ Rojas, O Ikkala, S Vignolini
– Advanced Materials
(2018)
30,
1704050
Bio-inspired Highly Scattering Networks via Polymer Phase Separation
J Syurik, G Jacucci, OD Onelli, H Hölscher, S Vignolini
– Advanced Functional Materials
(2018)
28,
1706901
Role of Anisotropy and Refractive Index in Scattering and Whiteness Optimization
G Jacucci, J Bertolotti, S Vignolini
– Advanced Optical Materials
1900980

Research Group

Telephone number

01223 334372 (shared)

Email address

gi232@cam.ac.uk