# Collapse of superhydrophobicity on nanopillared surfaces

## TL;DR

This study investigates how superhydrophobic surfaces with nanopillars lose their water-repelling properties underwater, revealing a collective wetting mechanism involving multiple pillars that previous models couldn't capture.

## Contribution

The paper demonstrates the importance of collective wetting mechanisms on nanopillared surfaces and introduces advanced atomistic simulations combined with continuum modeling to understand the collapse of superhydrophobicity.

## Key findings

- Wetting begins with liquid finger formation between two pillars.
- A collective wetting process involves multiple pillars simultaneously.
- Line tension and nanoscale effects are minor under the studied conditions.

## Abstract

The mechanism of the collapse of the superhydrophobic state is elucidated for submerged nanoscale textures forming a three-dimensional interconnected vapor domain. This key issue for the design of nanotextures poses significant simulation challenges as it is characterized by diverse time and length scales. State-of-the-art atomistic rare events simulations are applied for overcoming the long time scales connected with the large free energy barriers. In such interconnected surface cavities wetting starts with the formation of a liquid finger between two pillars. This break of symmetry induces a more gentle bend in the rest of the liquid-vapor interface, which triggers the wetting of the neighboring pillars. This collective mechanism, involving the wetting of several pillars at the same time, could not be captured by previous atomistic simulations using surface models comprising a small number of pillars (often just one). Atomistic results are interpreted in terms of a sharp-interface continuum model which suggests that line tension, condensation, and other nanoscale phenomena play a minor role in the simulated conditions.