s42004-019-0202-8.pdf (6.56 MB)
0/0

Liquid – liquid phase separation morphologies in ultra-white beetle scales and a synthetic equivalent

Download (6.56 MB)
journal contribution
posted on 02.09.2019 by Stephanie L Burg, Adam Washington, David M Coles, Antonino Bianco, Daragh Mcloughlin, Oleksandr O Mykhaylyk, Julie Villanova, Andrew JC Dennison, Christopher J Hill, Pete Vukusic, Scott Doak, Simon Martin, Mark Hutchings, Steven R Parnell, Cvetelin Vasilev, Nigel Clarke, Anthony J Ryan, Will Furnass, Mike Croucher, Robert M Dalgliesh, Sylvain Prevost, Rajeev Dattani, Andrew Parker, Richard AL Jones, J Patrick A Fairclough, Andrew J Parnell
Cyphochilus beetle scales are amongst the brightest structural whites in nature, being highly opacifying whilst extremely thin. However, the formation mechanism for the voided intra- scale structure is unknown. Here we report 3D x-ray nanotomography data for the voided chitin networks of intact white scales of Cyphochilus and Lepidiota stigma. Chitin-filling frac- tions are found to be 31 ± 2% for Cyphochilus and 34 ± 1% for Lepidiota stigma, indicating previous measurements overestimated their density. Optical simulations using finite- difference time domain for the chitin morphologies and simulated Cahn-Hilliard spinodal structures show excellent agreement. Reflectance curves spanning filling fraction of 5-95% for simulated spinodal structures, pinpoint optimal whiteness for 25% chitin filling. We make a simulacrum from a polymer undergoing a strong solvent quench, resulting in highly reflective ( 94%) white films. In-situ X-ray scattering confirms the nanostructure is formed through spinodal decomposition phase separation. We conclude that the ultra-white beetle scale nanostructure is made via liquid–liquid phase separation.
Logo branding

Categories

Keyword(s)

Funding

Innovate UK (Grant Number 33692-239251) in partnership with AkzoNobel and the University of Sheffield

History

School

  • Aeronautical, Automotive, Chemical and Materials Engineering

Department

  • Materials

Published in

Communications Chemistry

Volume

2

Publisher

Springer Nature

Version

VoR (Version of Record)

Rights holder

© The Authors

Acceptance date

02/08/2019

Publication date

2019-08-29

Copyright date

2019

eISSN

2399-3669

Language

en

Depositor

Dr Simon Martin

Article number

100

Licence

Exports

Logo branding

Categories

Keyword(s)

Licence

Exports