Roughness-dependent wetting behavior of vapor-deposited metallic thin films

Farnaz Foadi, S. Mehdi Vaez Allaei, George Palasantzas, Mohammad Reza Mohammadizadeh*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

5 Citations (Scopus)

Abstract

We studied the wetting behavior of silver and copper thin films versus their kinetic roughening upon deposition at room temperature on glass substrates. Time-dependent height-height correlation functions were extracted from atomic force microscopy images, and they demonstrated a nonstationary growth front of the film roughness associated with a temporal evolution of the local surface slope. As a result, we tried to correlate the roughness statistical properties such as the root-mean-square (rms) roughness sigma, the correlation length xi, and the local surface slope (rho approximate to sigma/xi) with the wetting behavior of the films' surfaces. The contact angle behavior was also studied by analyzing the variation of the energy of the system with water penetrating into the surface cavities, and the associated Laplace pressure induced by the local surface curvature. Hence, it was demonstrated that the wetting transition from a metastable Cassie-Baxter state to a Wenzel state as well as the penetration of a droplet into the surface crevices occur at the smaller local surface slopes for the higher surface energy material.

Original languageEnglish
Article number022804
Number of pages7
JournalPhysical Review E
Volume100
Issue number2
DOIs
Publication statusPublished - 26-Aug-2019

Keywords

  • SUPERHYDROPHOBIC SURFACES
  • WATER
  • HYDROPHILICITY
  • WETTABILITY

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