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  • Letter
  • Open Access

Origin of the inverse temperature dependence of hydrophobic attraction

Nigel B. Wilding* and Francesco Turci†

  • *Contact author: nigel.wilding@bristol.ac.uk
  • †Contact author: f.turci@bristol.ac.uk
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Phys. Rev. Research 7, L022079 – Published 30 June, 2025

DOI: https://doi.org/10.1103/66lz-1yw9

Abstract

Using enhanced sampling techniques, we have precisely characterized the water-mediated interactions between nanometer-sized spherical hydrophobic solutes. The interaction potential is captured with remarkable accuracy by a tailored morphometric theory that distills and integrates essential physical properties of the solvation shell. Notably, our simulations successfully replicate a previously poorly understood phenomenon: the anomalous strengthening of hydrophobic attraction with rising temperature. Our theory pinpoints the origin of this “inverse temperature” effect in the rapid thermal expansion of the solvation shell, a process driven by a critical drying transition. Intriguingly, this effect becomes increasingly pronounced with stronger solute-water van der Waals attraction, i.e., decreasing hydrophobicity—a subtle yet significant feature accounted for by our theory.

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Phys. Rev. Research 7, L022079– Published 30 June, 2025
  • Received 18 December 2024
  • Accepted 27 May 2025
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

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