Testing the limits of STAs. (IMAGE)
Caption
a, Lifetime τ of a water drop with initial volume 17 µl placed on STA brought to T = 1,000 °C. τ is normalized by the characteristic time τo of wicking (given in the text and by equation (3) in the Methods) and plotted as a function of the pore diameter d in the membrane. The STA is operational (blue data) when the pore size is large enough, typically above 1 µm, corresponding to τ > τo. b, Phase diagram of the STA, in a plot in which the parameters are the substrate temperature T and the channel height ε. STAs operate in the whole range of tested temperatures if ε is 150 µm; more generally, channels must be high enough to resist the flow of vapour. Shallow channels lead to an instability of the membrane, which is deformed and lifted by the massive production of vapour, whereas the absence of channels (ε = 0) leads to the undesired mixed state.
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© 2023 Research and Innovation Office, The Hong Kong Polytechnic University. All Rights Reserved.
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