Mimicking the Iridescence of Beetle Shells
Due to cellulose’s abundance, there is an increasing interest in using it as a basis for “developing renewable technologies… in areas including biofuel production and nanotechnology.” From (bulk) cellulose, under the right conditions, cellulose nanocrystals (CNCs), or nanocrystalline cellulose, can be isolated. Some of CNCs’ interesting properties include “their exceptional strength, high surface area, ease of functionalization, and self-assembly properties,” all of which have sparked various areas of research, including photonics. Photonics includes the study of the “generation, emission, transmission, modulation, signal processing, switching, amplification, and detection/sensing of light" Examples of phototonic structures in nature include iridescent (i.e. appears to change colours as the angle of view changes) insect shells (e.g. jewel beetles).
Recognizing that “coloration in nature plays essential roles in signaling, mimicry, or mate choice,” researchers have become increasingly interested in “developing new materials with controllable structural color for applications in sensing and optoelectronics [a sub-field of photonics]”. CNCs’ property of fast self-assembly (e.g. helical structures in water) make them good candidates in being used as a template for developing these structurally colored materials.
Dr. MacLachlan, from the University of British Columbia, and his research team found that “by using nanocrystalline cellulose and combining that with a glass precursor, [they] could transfer this structure, this helical structure of the cellulose into a porous glass.” As a result, Dr. MacLachlan and his team have been able to develop extremely unique glasses that mimic the iridescent shells of beetles, thus giving these glasses photonic properties, which they can control. One application Dr. MacLachlan and his team are looking at is coating building windows to reduce the amount of heating that occurs inside of the building, ultimately reducing the amount of air conditioning needed. I highly recommend watching this short clip of Dr. MacLachlan talking about his work with these unique glasses.
Photo courtesy of Gianfranco Merati
 K.E. Shopsowitz, J. A. Kelly, W. Y. Hamad, M. J. MacLachlan. Adv. Funct. Mater. 2014, 24, 327
 M. K. Kahn, M. Giese, M. Y, J. A. Kelly, W. Y. Hamad, M. J. MacLachlan. Angew. Chem. Int. 2013, 52, 8921
 NSERC Presents 2 Minutes With Mark MacLachlan (2012)