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Extent of Nonequilibrium Sets Relaxation Barriers in Dewetting Polymer Films

Mithun Madhusudanan1, Federico Caporaletti2, Jotypriya Sarkar1, Rohit V. Menon1, Sivasurender Chandran3, Ronald P. White4, Jane E. G. Lipson4,*, Simone Napolitano2,†, and Mithun Chowdhury1,‡

  • *Contact author: jane.lipson@dartmouth.edu
  • †Contact author: simone.napolitano@ulb.be
  • ‡Contact author: mithunc@iitb.ac.in
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Phys. Rev. Lett. 137, 118102 – Published 10 September, 2026

DOI: https://doi.org/10.1103/k28h-7blj

Abstract

Thin polymer films are archetypal nonequilibrium systems in which chain conformations are frozen by rapid preparation. The resulting molecular recoiling stress drives the system toward equilibrium and relaxes with time and temperature. We show that the activation energy governing this relaxation depends on the magnitude of the stress, revealing that polymers farther from equilibrium must overcome higher barriers, while stress release enables relaxation through progressively easier pathways. This stress-dependent evolution of activation barriers reflects a balance between energetic and entropic contributions and departs from the behavior typically observed for segmental mobility. Our experimental trends are quantitatively captured by the collective small displacements framework, consistent with recent observations of analogous relaxation behavior in adsorption-desorption, surface crystallization, and dipole reorientation. Our findings establish a direct link between nonequilibrium induced stress and molecular mobility, uncovering a general mechanism by which molecules reorganize toward equilibrium through localized, correlated motions.

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Outline

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Phys. Rev. Lett. 137, 118102– Published 10 September, 2026
  • Received 5 November 2025
  • Revised 12 February 2026
  • Accepted 10 August 2026
Article part of CHORUS
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