Dewetting of thin-film polymers

TL;DR

This paper develops a theoretical model for the dewetting process of ultra-thin polymer films, analyzing the morphology and dynamics based on shear-thinning behavior, and compares predictions with experimental data.

Contribution

It introduces a new theoretical framework incorporating a Cross-type constitutive equation to describe dewetting in thin polymer films, linking rheology to dewetting dynamics.

Findings

Power-law time dependence of dry radius and rim height in thin films

Different growth regimes depending on initial thickness and rheological parameters

Model predictions align with experimental observations by Debrégeas et al. and Reiter

Abstract

In this paper we present a theoretical model for the dewetting of ultra-thin polymer films. Assumming that the shear-thinning properties of these films can be described by a Cross-type constitutive equation, we analyze the front morphology of the dewetting film, and characterize the time evolution of the dry region radius, and of the rim height. Different regimes of growth are expected, depending on the initial film thickness, and on the power-law index involved in the constitutive equation. In the thin-films regime, the dry radius and the rim height obey power-law time dependences. We then compare our predictions with the experimental results obtained by Debr\'egeas {\it et al.} [Phys. Rev. Lett. {\bf 75}, 3886 (1995)] and by Reiter [Phys. Rev. Lett. {\bf 87}, 186101 (2001)].