Effect of film thickness and different electrode geometries on the performance of chemical sensors made of nanostructured conducting polymer films

In this contribution, the effect of film thickness and different microelectrode geometries on the performance of chemical sensors made of nanostructured films of conducting polymer poly(o-ethoxyaniline) (POEA) and sulfonated polystyrene (PSS) is investigated. Both parameters present significant influence on the sensors response. Depending upon the concentration of NaCl solutions, thicker films exhibit higher sensitivity to NaCl in comparison to thinner films according to impedance spectroscopy studies. The larger surface roughness of thicker films seems to be the main reason for such a behavior. Meanwhile, as the area of the gold electrodes is increased more sensitive sensors are obtained. At two different frequencies, namely 100 Hz and 1 kHz, the response of the sensors are found to be linear or exponentially dependent on the NaCl concentration. Furthermore, the sensors response is reproducible and NaCl can be detected at concentrations as low as 10 μM. The potential use of such sensors in an electronic tongue system is discussed.

[1]  I. Lundström,et al.  An electronic tongue based on voltammetry , 1997 .

[2]  F. B. Braz Fernandes,et al.  Counterions in poly(allylamine hydrochloride) and poly(styrene sulfonate) layer-by-layer films. , 2004, Langmuir : the ACS journal of surfaces and colloids.

[3]  Norman F. Sheppard,et al.  Electrical conductivity measurements using microfabricated interdigitated electrodes , 1993 .

[4]  S. V. Mello,et al.  An electronic tongue using polypyrrole and polyaniline , 2003 .

[5]  Changming Li,et al.  Fabrication of comb interdigitated electrodes array (IDA) for a microbead-based electrochemical assay system. , 2004, Biosensors & bioelectronics.

[6]  Fernando J. Fonseca,et al.  Artificial Taste Sensor: Efficient Combination of Sensors Made from Langmuir−Blodgett Films of Conducting Polymers and a Ruthenium Complex and Self-Assembled Films of an Azobenzene-Containing Polymer , 2002 .

[7]  A. G. Macdonald,et al.  AC admittance of the metal/insulator/electrolyte interface , 1987 .

[8]  Kiyoshi Toko.  Multichannel Taste Sensor with Lipid Membranes. , 1990 .

[9]  P. Bergveld,et al.  Theoretical and experimental determination of cell constants of planar-interdigitated electrolyte conductivity sensors , 1995 .

[10]  B. Tieke,et al.  Selective Ion Transport across Self-Assembled Alternating Multilayers of Cationic and Anionic Polyelectrolytes , 2000 .

[11]  Corrado Di Natale,et al.  Multicomponent analysis of heavy metal cations and inorganic anions in liquids by a non-selective chalcogenide glass sensor array , 1996 .

[12]  J. Schlenoff,et al.  Charge and Mass Balance in Polyelectrolyte Multilayers , 1998 .

[13]  D. De Rossi,et al.  Chemoresistive conducting polymer-based odour sensors: influence of thickness changes on their sensing properties , 1997 .

[14]  Leonardo G. Paterno,et al.  Study on the adsorption of poly(o-ethoxyaniline) nanostructured films using atomic force microscopy , 2005 .

[15]  A. Riul,et al.  An artificial taste sensor based on conducting polymers. , 2003, Biosensors & bioelectronics.

[16]  Michael Thompson,et al.  Applications of electronic noses and tongues in food analysis , 2004 .

[17]  Leonardo G. Paterno,et al.  Effect of pH on the preparation of self-assembled films of poly(o-ethoxyaniline) and sulfonated lignin , 2001 .

[18]  Gero Decher,et al.  Fuzzy Nanoassemblies: Toward Layered Polymeric Multicomposites , 1997 .

[19]  Alisa Rudnitskaya,et al.  Electronic tongues and their analytical application , 2002, Analytical and bioanalytical chemistry.

[20]  Josef Binder,et al.  Fluid characterization using sensor elements based on interdigitated electrodes , 1996 .

[21]  A. Epstein,et al.  Studies on the Chemical Syntheses and on the Characteristics of Polyaniline Derivatives , 1995 .