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A time‐based potential step analysis of electrochemical impedance incorporating a constant phase element: A study of commercially pure titanium in phosphate buffered saline
Author(s) -
Ehrensberger Mark T.,
Gilbert Jeremy L.
Publication year - 2010
Publication title -
journal of biomedical materials research part a
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.849
H-Index - 150
eISSN - 1552-4965
pISSN - 1549-3296
DOI - 10.1002/jbm.a.32550
Subject(s) - constant phase element , materials science , electrical impedance , dielectric spectroscopy , capacitance , resistor , equivalent circuit , frequency domain , time constant , time domain , admittance , analytical chemistry (journal) , voltage , electrode , electrochemistry , electrical engineering , computer science , chemistry , chromatography , computer vision , engineering
The measurement of electrochemical impedance is a valuable tool to assess the electrochemical environment that exists at the surface of metallic biomaterials. This article describes the development and validation of a new technique, potential step impedance analysis (PSIA), to assess the electrochemical impedance of materials whose interface with solution can be modeled as a simplified Randles circuit that is modified with a constant phase element. PSIA is based upon applying a step change in voltage to a working electrode and analyzing the subsequent current transient response in a combined time and frequency domain technique. The solution resistance, polarization resistance, and interfacial capacitance are found directly in the time domain. The experimental current transient is numerically transformed to the frequency domain to determine the constant phase exponent, α. This combined time and frequency approach was tested using current transients generated from computer simulations, from resistor–capacitor breadboard circuits, and from commercially pure titanium samples immersed in phosphate buffered saline and polarized at −800 mV or +1000 mV versus Ag/AgCl. It was shown that PSIA calculates equivalent admittance and impedance behavior over this range of potentials when compared to standard electrochemical impedance spectroscopy. This current transient approach characterizes the frequency response of the system without the need for expensive frequency response analyzers or software. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res, 2010