Spreading Dynamics of a Precursor Film of Ionic Liquid or Water on a Micropatterned Polyelectrolyte Brush Surface

Shohei Shiomoto, Hayato Higuchi, Kazuo Yamaguchi, Hiromitsu Takaba, Motoyasu Kobayashi

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)

Abstract

Time evolution of the microscopic wetting velocity of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMI-TFSI) or water on a micrometer-scale line-patterned surface with a poly(3-sulfopropyl methacrylate) brush and a hydrophobic perfluoroalkyl monolayer was precisely measured by direct observation using optical microscopy and a selective dyeing method over a long period (178 days). When a liquid droplet was placed on the dyed line-patterned brush surface, the liquid penetrated and spread into the polymer brush layer, forming a precursor thin film that extended beyond the macroscopic contact line. The elongation proceeded in two stages by an adiabatic process followed by a diffusive process. The elongation distance X increased with time in proportion to t2.6 for water and t0.81 for EMI-TFSI during the adiabatic process. In a diffusive process, the advancing velocity of the precursor film was markedly reduced to be expressed as X ∝ t0.66 for water and X ∝ t0.21 for EMI-TFSI, indicating that the diffusive process was affected by the energy dissipation of the wetting system. The high viscosity and the strong molecular interaction of EMI-TFSI with the polymer brush gave a large entropy change during the wetting process to result in a slower spreading velocity.

Original languageEnglish
Pages (from-to)3049-3056
Number of pages8
JournalLangmuir
Volume37
Issue number10
DOIs
Publication statusPublished - Mar 16 2021
Externally publishedYes

All Science Journal Classification (ASJC) codes

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

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