Cellulose bio-inspired hierarchical structures

Silvia Vignolini (Cambridge University) — June 30, 2016

Nature’s most vivid colours rely on the ability to produce complex and hierarchical photonic structures with lattice constants on the order of the wavelength of visible radiation [1]. A recurring strategy design that is found both in the animal and plant kingdoms for producing such effects is the helicoidal architecture [2,3]. In such structures, a series of individual nano-fibers (made of natural polymers as cellulose and chitin) are arranged parallel to each other in stacked planes. When distance between such planes is comparable to the wavelength of light, a strong polarised, colour selective response can be obtained. These helicoidal multilayers are generally structured on the micro-scale and macroscopic scale, giving rise to hierarchical structures with a complex optical response.
Biomimetic with cellulose-based architectures enables us to fabricate novel photonic structures using low cost materials in ambient conditions [4-5]. Importantly, it also allows us to understand the biological processes at work during the growth of these structures in plants. In this talk the route for the fabrication of complex bio-mimetic cellulose-based photonic structures will be presented and the optical properties of artificial structures will be analysed and compared with the natural ones.

1. Kinoshita S. et al. (2008). Physics of structural colors. Rep. Prog. Phys. 71(7), 076401.
2. Vignolini S. et al. (2012). Pointillist structural color in Pollia fruit PNAS 109, 15712-15716.
3. Wilts B. D, et al. (2014). Natural Helicoidal Structures : Morphology, Self-assembly and Optical Properties. Materials Today : Proceedings, 1, 177–185.
4. Dumanli A. et al. (2014) Digital Color in Cellulose Nanocrystal Films, ACS Appl. Mater. Interfaces ACS Appl. Mater. Interfaces 6, 12302
5. Dumanli A. et al. (2014) Controlled bio-inspired self-assembly of cellulose-based chiral reflectors, Adv. Opt. Mat. 2, 646

Biography :
Dr. Silvia Vignolini studied Physics at the University of Florence, Italy. In 2009, she was awarded a PhD in Physics at the European Laboratory for non-Linear Spectroscopy and the Physics Department at the University of Florence. During her PhD, she studied light-matter interaction in the near-field regime under the supervision of Prof. D. Wiersma. In 2010, she joined the group of Prof. U. Steiner as a Research Associate at the Cavendish Laboratory in Cambridge, UK, working on optical properties of soft materials. In 2013 she has been awarded a BBSRC David Philip Fellowship. She joined the Chemistry Department in Cambridge as a Lecturer in 2014, and in 2015 she has been awarded an ERC Starting Grant.

You can also watch this video on the multimedia site ENS : savoirs.ens.fr