When and how self-cleaning of superhydrophobic surfaces works

Research output: Contribution to journalArticle

Authors

  • Florian Geyer
  • Maria D’Acunzi
  • Azadeh Sharifi-Aghili
  • Alexander Saal
  • Anke Kaltbeitzel
  • Tim Frederik Sloot
  • Rüdiger Berger
  • Hans Jürgen Butt
  • Doris Vollmer

Colleges, School and Institutes

External organisations

  • Evonik Resource Efficiency GmbH
  • Max Planck Institute for Polymer Research

Abstract

Despite the enormous interest in superhydrophobicity for self-cleaning, a clear picture of contaminant removal is missing, in particular, on a single-particle level. Here, we monitor the removal of individual contaminant particles on the micrometer scale by confocal microscopy. We correlate this space- and time-resolved information with measurements of the friction force. The balance of capillary and adhesion force between the drop and the contamination on the substrate determines the friction force of drops during self-cleaning. These friction forces are in the range of micro-Newtons. We show that hydrophilic and hydrophobic particles hardly influence superhydrophobicity provided that the particle size exceeds the pore size or the thickness of the contamination falls below the height of the protrusions. These detailed insights into self-cleaning allow the rational design of superhydrophobic surfaces that resist contamination as demonstrated by outdoor environmental (>200 days) and industrial standardized contamination experiments.

Details

Original languageEnglish
Article numbereaaw9727
Pages (from-to)1-11
Number of pages11
JournalScience Advances
Volume6
Issue number3
Publication statusPublished - 17 Jan 2020

ASJC Scopus subject areas