Electrical impedance spectroscopy characterisation of supported ionic liquid membranes

Raquel Fortunato, Luís C. Branco, Carlos A. M. Afonso, Juana Benavente, João G. Crespo

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66 Citations (Scopus)


Supported liquid membranes (SLMs), prepared by immobilising the room temperature ionic liquids (RTILs) [CnMIM]PF6 (n = 4 and 8) and [C10MIM]BF4 in a polyvinylidene (PVDF) supporting membrane, were prepared and characterised by electrochemical impedance spectroscopy (IS). This non-invasive technique allows the determination of the electrical properties of a given sample, such as the electrical resistance and capacitance under working conditions, i.e., in contact with saline solutions. Bearing in mind that the water content of the ionic liquids can drastically affect their physicochemical properties, impedance measurements of the SLMs, placed between two aqueous solutions, were carried out at regular time intervals, in order to assess the impact of the presence of water inside the RTILs on the electrical properties of supported ionic liquid membranes. The electrical resistance of the SLMs and its variation during long-term operation was also used as a physical parameter to identify the presence/loss of ionic liquid from the pores of the support. Additionally, the comparison of the IS results obtained for the SLMs with those obtained for the supporting membrane was carried out, in order to gather information about electrical changes associated with the presence of ionic liquid in the pores.

Original languageEnglish
Pages (from-to)42-49
Number of pages8
JournalJournal of Membrane Science
Issue number1-2
Publication statusPublished - 15 Feb 2006


  • Impedance spectroscopy
  • Ion-conducting membranes
  • Ionic liquids
  • Liquid membranes
  • Membrane stability

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