Electrical conductance of hydrophobic membranes or what happens below the surface

Ivan Vlassiouk, Fabian Rios, Sean A. Vail, John Devens Gust, Sergei Smirnov

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

Nanoporous alumina membranes rendered hydrophobic by surface modification via covalent attachment of hydrocarbon or fluorocarbon chains conduct electricity via surface even when the pores are not filled with electrolyte. The resistance is many orders of magnitude higher than for electrolyte-filled membranes and does not depend on the electrolyte concentration or pH, but it does depend on the type of hydrophobic monolayer and its density. The corresponding surface resistance varies from greater than 10 18 Ω per square to less than 3 × 10 9 Ω per square. When the hydrophobic monolayer contains a small proportion of photoactive spiropyran that is insufficient to switch the surface to hydrophilic after spiropyran photoisomerization to the merocyanine form, the membrane resistance also becomes light-dependent with a reversible increase of surface resistance by as much as 15%. Surface conduction is ascribed to hydration and ionization of the alumina surface hydroxyls and the ionizable groups of the hydrophobic surface modifiers.

Original languageEnglish
Pages (from-to)7784-7792
Number of pages9
JournalLangmuir
Volume23
Issue number14
DOIs
Publication statusPublished - Jul 3 2007

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membranes
Membranes
Electrolytes
Surface resistance
Aluminum Oxide
Monolayers
Alumina
electrolytes
Fluorocarbons
Photoisomerization
Hydrocarbons
aluminum oxides
Hydration
Hydroxyl Radical
Ionization
Surface treatment
Electricity
Switches
fluorocarbons
electricity

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Colloid and Surface Chemistry

Cite this

Electrical conductance of hydrophobic membranes or what happens below the surface. / Vlassiouk, Ivan; Rios, Fabian; Vail, Sean A.; Gust, John Devens; Smirnov, Sergei.

In: Langmuir, Vol. 23, No. 14, 03.07.2007, p. 7784-7792.

Research output: Contribution to journalArticle

Vlassiouk, I, Rios, F, Vail, SA, Gust, JD & Smirnov, S 2007, 'Electrical conductance of hydrophobic membranes or what happens below the surface', Langmuir, vol. 23, no. 14, pp. 7784-7792. https://doi.org/10.1021/la070038q
Vlassiouk, Ivan ; Rios, Fabian ; Vail, Sean A. ; Gust, John Devens ; Smirnov, Sergei. / Electrical conductance of hydrophobic membranes or what happens below the surface. In: Langmuir. 2007 ; Vol. 23, No. 14. pp. 7784-7792.
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