Quantifying density fluctuations in water at a hydrophobic surface: evidence for critical drying

Robert Evans, Nigel B. Wilding

Research output: Contribution to journalLetter

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Employing smart Monte Carlo sampling techniques within the grand canonical ensemble, we investigate the properties of water at a model hydrophobic substrate. By reducing the strength of substrate-water attraction we find that fluctuations in the local number density, quantified by a rigorous definition of the local compressibility $\chi(z)$, increase rapidly for distances $z$ within $1$ or $2$ molecular diameters from the substrate as the degree of hydrophobicity, measured by the macroscopic contact angle $\theta$, increases. Our simulations provide evidence for a continuous (critical) drying transition as the substrate-water interaction becomes very weak: $\cos(\theta)\to -1$. We speculate that the existence of such a transition might account for earlier simulation observations of strongly enhanced density fluctuations.
Original languageEnglish
Article number016103
Pages (from-to)1-5
Number of pages5
JournalPhysical Review Letters
Issue number1
Early online date2 Jul 2015
Publication statusPublished - 3 Jul 2015


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