Kevin P. Raymond, Ian B. Burgess, Mackenzie H. Kinney, Marko Lončar and Joanna Aizenberg
Lab Chip, 2012,12, 3666-3669
DOI:
10.1039/C2LC40489C,
Communication
We present a colourimetric litmus test for simple differentiation of organic liquids based on wetting, which achieves chemical specificity without a significant sacrifice in portability or ease-of-use. Chemical specificity is derived from the combination of colourimetric wetting patterns produced by liquids in an array of inverse opal films, each having a graded wettability, but using different surface groups to define that gradient.