Effect of the initial solute concentration on the flow pattern inside an evaporating polymer solution droplet on a substrate

Masayuki Kaneda, Hirotaka Ishizuka, Kentarou Hyakuta, Jun Fukai

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Citation (Scopus)

Abstract

The internal flow of an evaporating polymer solution droplet on a substrate is experimentally studied. The flow visualization is carried out. The effect of the initial polymer concentration is further investigated. A polystyrene-acetophenone (PS-Ap) and a polystyrene-anisole (PS-Ani) solution are employed as the droplet. A nylon powder is mixed with the droplet for the visualization by a YAG-laser sheet light. The droplet evaporates after the settlement on the substrate. Without the polymer dissolved in the solvent, complicated flow is observed in both droplets. For the cases with dissolved polymer, the flow pattern is rectified. In the PS-Ap droplet, the source flow is observed for the initial solute mass fraction c0 = 0.005 - 0.20. This convection becomes strong as c0 increases. The mechanism of the flow inside the PS-Ap droplet can be understood by the combination of the natural convection and Marangoni convection due to the differences of the temperature and the solute concentration. As for the PS-Ani droplet, the evaporation process and the flow pattern are affected by c0. For the dilute solution (0 < c0 < 0.03), the contact angle decreases during the contact line receding. The observed flow pattern becomes similar to that in the PS-Ap droplet. At c0 = 0.08 - 0.2, the decline of the contact angle is remarkable and the direction of the internal flow becomes inverse. This flow mechanism cannot be clarified, but it may have the relations with the decreasing contact angle.

Original languageEnglish
Title of host publication2007 Proceedings of the ASME/JSME Thermal Engineering Summer Heat Transfer Conference - HT 2007
PublisherAmerican Society of Mechanical Engineers (ASME)
Pages1091-1097
Number of pages7
ISBN (Print)0791842746, 9780791842744
DOIs
Publication statusPublished - Jan 1 2007
Event2007 ASME/JSME Thermal Engineering Summer Heat Transfer Conference, HT 2007 - Vancouver, BC, Canada
Duration: Jul 8 2007Jul 12 2007

Publication series

Name2007 Proceedings of the ASME/JSME Thermal Engineering Summer Heat Transfer Conference - HT 2007
Volume1

Other

Other2007 ASME/JSME Thermal Engineering Summer Heat Transfer Conference, HT 2007
CountryCanada
CityVancouver, BC
Period7/8/077/12/07

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All Science Journal Classification (ASJC) codes

  • Management, Monitoring, Policy and Law
  • Fuel Technology
  • Renewable Energy, Sustainability and the Environment
  • Energy(all)
  • Electrical and Electronic Engineering
  • Mechanical Engineering
  • Condensed Matter Physics
  • Energy Engineering and Power Technology
  • Modelling and Simulation

Cite this

Kaneda, M., Ishizuka, H., Hyakuta, K., & Fukai, J. (2007). Effect of the initial solute concentration on the flow pattern inside an evaporating polymer solution droplet on a substrate. In 2007 Proceedings of the ASME/JSME Thermal Engineering Summer Heat Transfer Conference - HT 2007 (pp. 1091-1097). (2007 Proceedings of the ASME/JSME Thermal Engineering Summer Heat Transfer Conference - HT 2007; Vol. 1). American Society of Mechanical Engineers (ASME). https://doi.org/10.1115/HT2007-32718