Effect of material flexibility on the thermodynamics and kinetics of hydrophobically induced evaporation of water

Y. Elia Altabet, Amir Haji-Akbari, Pablo G. Debenedetti

Research output: Contribution to journalArticle

27 Scopus citations

Abstract

The evaporation of water induced by confinement between hydrophobic surfaces has received much attention due to its suggested functional role in numerous biophysical phenomena and its importance as a general mechanism of hydrophobic self-Assembly. Although much progress has been made in understanding the basic physics of hydrophobically induced evaporation, a comprehensive understanding of the substrate material features (e.g., geometry, chemistry, and mechanical properties) that promote or inhibit such transitions remains lacking. In particular, comparatively little research has explored the relationship between water's phase behavior in hydrophobic confinement and the mechanical properties of the confining material. Here, we report the results of extensive molecular simulations characterizing the rates, free energy barriers, and mechanism of water evaporation when confined between model hydrophobic materials with tunable flexibility. A single-order-of-magnitude reduction in the material's modulus results in up to a nine-orders-ofmagnitude increase in the evaporation rate, with the corresponding characteristic time decreasing from tens of seconds to tens of nanoseconds. Such a modulus reduction results in a 24-orders-of-magnitude decrease in the reverse rate of condensation, with time scales increasing from nanoseconds to tens of millions of years. Free energy calculations provide the barriers to evaporation and confirm our previous theoretical predictions that making the material more flexible stabilizes the confined vapor with respect to liquid. The mechanism of evaporation involves surface bubbles growing/coalescing to form a subcritical gap-spanning tube, which then must grow to cross the barrier.

Original languageEnglish (US)
Pages (from-to)E2548-E2555
JournalProceedings of the National Academy of Sciences of the United States of America
Volume114
Issue number13
DOIs
StatePublished - Mar 28 2017

All Science Journal Classification (ASJC) codes

  • General

Keywords

  • Elasticity
  • Evaporation
  • Hydrophobic effect
  • Nanoconfinement
  • Phase transitions

Fingerprint Dive into the research topics of 'Effect of material flexibility on the thermodynamics and kinetics of hydrophobically induced evaporation of water'. Together they form a unique fingerprint.

  • Cite this