Speaker
Dr
Christopher Garvey
(ANSTO)
Description
Wing scales of some butterfly and beetle species contain bicontinuous phases of polymer, largely chitin, and air filled voids. The single network gyroid phase I4132 has been identified as the structure present in butterfly wing scales of several butterfly species with green wing scales [1,2,3]. We have also identified the diamond phase in the wings of in the diamond weevil, Entimus imperialis.. The periodic length scales of these phases is such that it produces optical responses that may relate to insect communication, such as discriminating response to circularly polarized light [4].
In principle diffraction techniques have the possibility of mapping the characteristic length-scales and orientation(s) of the unit cells, but also the nature of defects in crystalline lattice, on the wings of butterflies. This information will provide insight into the mechanism and, potentially, the technological control of such photonic structures. Such information may be characterized by obtaining a sufficient angular range to obtain the position of all diffraction peaks and sufficient angular resolution to characterize their shape. These cubic phases have very large unit cells (> 200 nm) and so measurements push the limits of conventional pin-hole SAXS instrumentation both in terms of the minimum angle but also angular resolution close to the beam stop.
[1] Michielsen, K., D.G Stavenga. J. R. Soc. Interface: 5(18) 85-94 (2008)
[2] Saranathan, V., C. O. Osuji, S. G. J. Mochrie, H. Noh, S. Narayanan, A. Sandy, E. R. Dufresne, and R. O. Prum. PNAS: 107(26) 11676-11681 (2010)
[3] Schröder-Turk GE, Wickham S, Averdunk H, Brink F, Fitz Gerald JD, Poladian L, Large MC, Hyde ST. J Struct Biol: 174(2) 290-5 (2011)
[4] Saba, M, M. Thiel, M. D. Turner, S. T. Hyde, M. Gu, K. Grosse-Brauckmann, D. N. Neshev, K. Mecke, and G. E. Schröder-Turk, Phys. Rev. Lett. 106, 103902 (2011)
Primary author
Dr
Christopher Garvey
(ANSTO)
