Effect of TiO2 Nanoparticles on Contact Line Stick-Slip Behavior of Volatile Drops

J. Ross Moffat*, Khellil Sefiane, Martin E. R. Shanahan

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

We describe an experimental investigation of the concomitant evaporation and (de)wetting behavior of sessile drops of ethanol, either pure, or containing small amounts of titanium oxide nanoparticles. Pure ethanol behaved in a more or less "ideal" manner, with constantly decreasing contact radius, at essentially constant contact angle. However, distinct "stick-slip" pinning behavior of the triple line occurred when nanoparticles were added to the base liquid. Increased nanoparticle concentration enhanced the "stick-slip" behavior. The observed behavior is attributed to the effects of particle accumulation near the contact line, caused by the now-established advective flow during evaporation. "Slip" behavior call lie explained by hysteretic energy barriers, somewhat akin to line tension. The "stick" behavior was not complete: some triple line drift occurred ("pseudo-pinning"). It is postulated that this may be due to small-scale pinning of the triple line by deposited particles, or to increased effective viscosity due to high, local nanoparticle concentrations.

Original languageEnglish
Pages (from-to)8860-8866
Number of pages7
JournalJournal of Physical Chemistry B (Soft Condensed Matter and Biophysical Chemistry)
Volume113
Issue number26
DOIs
Publication statusPublished - 2 Jul 2009

Keywords

  • WATER-BASED NANOFLUIDS
  • THERMAL-CONDUCTIVITY
  • EVAPORATION
  • SESSILE
  • FLUIDS
  • WETTABILITY
  • HYSTERESIS
  • VISCOSITY
  • DROPLETS
  • SURFACES

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