Precursor-Film-Mediated Thermocapillary Motion of Low-Surface-Tension Microdroplets

Hideaki Teshima, Sirshendu Misra, Koji Takahashi, Sushanta K. Mitra

Research output: Contribution to journalArticle

Abstract

In contrast to microdroplet condensation with high contact angles, the one with low contact angles remains unclear. In this study, we investigated dynamics of microdroplet condensation of low-surface-tension liquids on two flat substrate surfaces by using reflection interference confocal microscopy. Spontaneous migration toward relatively larger droplets was first observed for the microdroplets nucleated on the hydrophilic quartz surface. The moving microdroplets showed a contact angle hysteresis of ∼0.5°, which is much lower than the values observed on typical flat substrates and is within the range observed on slippery lubricant-infused porous surfaces. Because the microdroplets on the hydrophobic polydimethylsiloxane surface did not move, we concluded that the ultrathin precursor film is formed only on the hydrophilic surface, which reduces a resistive force to migration. Also, reduced size of droplets promotes the thermocapillary motion, which is induced by a gradient in local temperature inside a small microdroplet arising due to the difference in size of adjacent droplets.

Original languageEnglish
Pages (from-to)5096-5105
Number of pages10
JournalLangmuir : the ACS journal of surfaces and colloids
Volume36
Issue number19
DOIs
Publication statusPublished - May 19 2020

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Spectroscopy
  • Electrochemistry

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