@article {968926, title = {Wetting in Color: From photonic fingerprinting of liquids to optical control of liquid percolation}, journal = {Proc. of SPIE}, volume = {8632}, year = {2013}, pages = {863201}, abstract = {

We provide an overview of our recent advances in the manipulation of wetting in inverse-opal photonic crystals. Exploiting photonic crystals with spatially patterned surface chemistry to confine the infiltration of fluids to liquidspecific spatial patterns, we developed a highly selective scheme for colorimetry, where organic liquids are distinguished based on wetting. The high selectivity of wetting, upon-which the sensitivity of the response relies, and the bright iridescent color, which disappears when the pores are filled with liquid, are both a result of the highly symmetric pore structure of our inverse-opal films. The application of horizontally or vertically orientated gradients in the surface chemistry allows a unique response to be tailored to specific liquids. While the generic nature of wetting makes our approach to colorimetry suitable for applications in liquid authentication or identification across a broad range of industries, it also ensures chemical non-specificity. However, we show that chemical specificity can be achieved combinatorially using an array of indicators that each exploits different chemical gradients to cover the same dynamic range of response. Finally, incorporating a photo-responsive polyelectrolyte surface layer into the pores, we are able to dynamically and continuously photo-tune the wetting response, even while the film is immersed in liquid. This in situ optical control of liquid percolation in our photonic-crystal films may also provide an error-free means to tailor indicator response, naturally compensating for batch-to-batch variability in the pore geometry.

}, url = {https://www.spiedigitallibrary.org/conference-proceedings-of-spie/8632/1/Wetting-in-color--from-photonic-fingerprinting-of-liquids-to/10.1117/12.2013366.short?SSO=1}, author = {Burgess, I.B. and B.A. Nerger and K.P. Raymond and A. Goulet-Hanssens and T.A. Singleton and M.H. Kinney and Shneidman, A.V. and N. Koay and C.J. Barrett and Loncar, M. and Aizenberg, J.} }