ORIGINAL PAPER Electrolyte type and concentration effects on poly(3-(2- aminoethyl thiophene) electro-coated on glassy carbon electrode via impedimetric study Murat Ates • Tolga Karazehir • Fatih Arican • Nuri Eren Received: 31 July 2012 / Accepted: 19 December 2012 / Published online: 9 January 2013 Ó Iran Polymer and Petrochemical Institute 2012 Abstract In this study, 3-(2-Aminoethyl thiophene) (2AET) monomer was electropolymerized on glassy car- bon electrode (GCE) using various electrolytes (lithium perchlorate (LiClO 4 ), sodium perchlorate (NaClO 4 ), tetra- butyl ammonium tetra fluoroborate (TBABF 4 ) and tetra- ethyl ammonium tetra fluoroborate (TEABF 4 ) in acetonitrile (CH 3 CN) as solvent. Poly(3-(2-aminoethyl thiophene) (P(2AET))/GCE was characterized by cyclic voltammetry (CV), Fourier transform infrared reflectance spectrophotometry (FTIR-ATR), scanning electron microscopy, energy dispersive X-ray analysis (EDX), and electrochemical impedance spectroscopy (EIS) techniques. The electrochemical impedance spectroscopic results were given by Nyquist, Bode-magnitude, Bode-phase, capaci- tance and admittance plots. The highest low frequency capacitance (C LF ) value obtained was 0.65 mF cm -2 in 0.1 M LiClO 4 /CH 3 CN for the initial monomer concentra- tion of 1.5 mM. The highest double layer capacitance (C dl = ~0.63 mF cm -2 ) was obtained in 0.1 M LiClO 4 / ACN for [2AET] 0 = 0.5, 1.0 and 1.5 mM. The maximum phase angles (h = 76.1 o at 26.57 Hz) and conductivity (Y 00 = 3.5 mS) were obtained in TEABF 4 /ACN for [2AET] 0 = 0.5 and 1.0 mM, respectively. An equivalent circuit model of R(Q(R(Q(R(CR))))) was simulated for different electrolytes (LiClO 4 , NaClO 4 , TBABF 4 and TEABF 4 )/P(2AET)/GCE system. A good fitting was obtained for the calculated experimental and theoretical EIS measurement results. The electroactivity of P(2AET)/ GCE opens the possibility of using modified coated elec- trodes for electrochemical micro-capacitor electrodes and biosensor applications. Keywords 3-(2-Aminoethyl thiophene)  Electrolyte  Scanning electron microscopy  Concentration  Circuit model Introduction Conjugated electroactive polymers have increasingly become of significant interest worldwide due to their inherently physical, mechanical and electronic properties [1]. The modification by functionalization of the electro- active monomer before polymerization [2–4], based on the electronic properties of the neutral semiconducting form of conjugated systems has had a great effect on the polymer chemistry [5, 6]. The aspects of physical, mechanical and electronic properties have been studied in charge storage devices which were lightweight, formable, and redox stable [7]. Conducting polymers were prepared either by chemical or electrochemical polymerization. The electrochemical synthesis offers several advantages, including rapidity, simplicity, generation of the polymer in the doped state and easy control of thickness of the film generated [8, 9]. Functional conjugated polymers show good electro-activity due to their electro generation on the electrode surface [10–14]. Due to their good processability and, outstanding chemical and electrochemical stability, conducting poly- mers have attracted more attentions and are expected to be M. Ates (&)  T. Karazehir  F. Arican  N. Eren Department of Chemistry, Faculty of Arts and Sciences, Namik Kemal University, Degirmenalti Campus, 59030 Tekirdag, Turkey e-mail: mates@nku.edu.tr URL: http://mates-en.nku.edu.tr/ T. Karazehir Department of Chemistry, Faculty of Arts and Sciences, Istanbul Technical University, Maslak, Istanbul, Turkey Iran Polymer and Petrochemical Institute 123 Iran Polym J (2013) 22:199–208 DOI 10.1007/s13726-012-0117-z