Impedance study of thiolated polyaniline

Abstract

Covalent attachment of thiolated probes to conducting polymers such as polyaniline (PANI) is a promising approach towards the development of electrochemical sensors and biosensors. However, thiolation alters the conjugated polymer backbone and influences the electrochemical behavior of the conducting polymer. PANI studied in this work was electropolymerized on glassy carbon (GC) electrodes from a solution of 0.1 M aniline in 0.5 or 1.0 M H 2 SO 4 . The GC/PANI electrodes were then functionalized by covalent attachment of 2-mercaptoethanol to the PANI backbone. The progress of thiolation was studied by cyclic voltammetry and electrochemical impedance spectroscopy (EIS). Thiolation of PANI was found to cause an initial decrease in electroactivity at 0-0.25 V and an increase in electroactivity at 0.25-0.6 V. However, prolonged thiolation caused a loss of electroactivity of PANI, which could be seen from EIS measurements as a dramatic decrease in the bulk redox capacitance of PANI.

Conducting polyaniline based cell culture substrate for embryonic stem cells and embryoid bodies

“…With the latter method it is possible to precisely direct the PANI lm formation on small electrically conducting substrates (e.g., electrode arrays) which can then be used, for example, as the ion-to-electron transducer in all-solidstate ion-selective electrodes. [11][12][13] The electropolymerization of aniline has usually been carried out in aqueous solutions containing inorganic acids, e.g., sulfuric acid, [14][15][16] perchloric acid, 15 nitric acid, 14 or phosphoric acid, 17 or in solutions of organic acids, e.g., p-toluenesulfonic acid. 18 It can also be done in the presence of polymeric acids such as poly(styrenesulfonic acid) 19 or PAMPSA, [20][21][22][23][24] and also in organic solvents, e.g., acetonitrile [25][26][27] or dichloromethane.…”