title: Electrochemical Impedance Spectroscopy in a Droplet of Solution for the Investigation of Liquid/Solid Interface.
abstract: The local electrochemical behavior of a solid-liquid interface can be studied by electrochemical impedance spectroscopy (EIS). The investigated surface area can be delimited by adding a drop of solution, which forms an interface between the liquid drop and the working electrode, and performing the measurements inside. The size of the drop must be sufficiently small for a simultaneous wettability characterization (from the contact angle measurement) and appropriately large so that wettability is not influenced by the presence of the working and the counter electrode inserted in the droplet. In this work, we showed that EIS measurements can be performed in a solution droplet of 2 to 4 μL, although the electrochemical cell lacks the usual geometry. For our measurements, we studied a model system consisting of a KCl aqueous solution of [Fe(CN)6]3-/4-redox couple at a Pt electrode. All the results were compared with those obtained for a bulk configuration. The sessile drop configuration and the EIS response were modeled using finite element method for different electrode sizes and configurations to account for electrochemical kinetics and both current and potential distributions.
authors.affiliation: Sorbonne Universités , UPMC Univ Paris 06, CNRS, Laboratoire Interfaces et Systèmes Electrochimiques, 4 Place Jussieu, F-75005 Paris, France.|Departamento de Eng. Metalúrgica e de Materiais, Universidade de São Paulo , Av. Prof. Mello Moraes, n. 2463, CEP 05508-030 São Paulo, São Paulo, Brazil.
authors.forename: Camila
authors.initials: C
authors.lastname: Molena de Assis
authors.affiliation: Sorbonne Universités , UPMC Univ Paris 06, CNRS, Laboratoire Interfaces et Systèmes Electrochimiques, 4 Place Jussieu, F-75005 Paris, France.
authors.forename: Thu Huong
authors.initials: TH
authors.lastname: Ho
authors.affiliation: Departamento de Eng. Metalúrgica e de Materiais, Universidade de São Paulo , Av. Prof. Mello Moraes, n. 2463, CEP 05508-030 São Paulo, São Paulo, Brazil.
authors.forename: Hercilio Gomes
authors.initials: HG
authors.lastname: de Melo
authors.affiliation: Sorbonne Universités , UPMC Univ Paris 06, CNRS, Laboratoire Interfaces et Systèmes Electrochimiques, 4 Place Jussieu, F-75005 Paris, France.
authors.forename: Michel
authors.initials: M
authors.lastname: Keddam
authors.affiliation: Sorbonne Universités , UPMC Univ Paris 06, CNRS, Laboratoire Interfaces et Systèmes Electrochimiques, 4 Place Jussieu, F-75005 Paris, France.
authors.forename: Mireille
authors.identifier: 0000-0002-5939-5065
authors.initials: M
authors.lastname: Turmine
authors.affiliation: Sorbonne Universités , UPMC Univ Paris 06, CNRS, Laboratoire Interfaces et Systèmes Electrochimiques, 4 Place Jussieu, F-75005 Paris, France.
authors.forename: Vincent
authors.initials: V
authors.lastname: Vivier