Poly-o-toluidine coated polyvinyl alcohol film: Reaction driven sensing capabilities

Abstract

Conducting polymers have the ability to self-sense the surrounding working ambient through their unique electrochemical reactions based on the ionic and aqueous exchanges with the electrolyte. The reaction-driven sensing characteristics of poly-o-toluidine/polyvinyl alcohol hybrid film fabricated through in situ chemical polymerization of o-toluidine on polyvinyl alcohol film are presented. The resulted hybrid film comprised of mixed coral and agglomerated granular morphology of poly-o-toluidine grown on the surface of the film with sufficient porosity and surface area. Cyclic voltammograms revealed two pairs of redox peaks and verified that the electroactivity of the hybrid film is imparted by poly-o-toluidine. The coulovoltammetric response of the hybrid film is closed in an acidic aqueous solution, suggesting that only reversible POT redox reactions take place in the studied potential interval. The sensing abilities of the hybrid film with regard to applied current and electrolyte concentration monitored by square current waves (under galvanostatic conditions) at a constant charge (to achieve the same reaction extension) shows that the consumed electrical energy has a linear relation with the applied current (working electrical condition) and a semi-logarithmic relation with the concentration of electrolyte (working chemical condition). Thus any reactive device based on the redox reactions of POT/PVA hybrid film can respond to, adapt to and sense the surrounding working conditions.