Electrokinetic properties of biodegradable conducting polyaniline-graft-chitosan copolymer in aqueous and non-aqueous media

Abstract

In this study, biodegradable and conducting polyaniline-graft-chitosan (PAni-g-CS) copolymer was synthesized by radicalic polymerization using ammonium persulfate (NH4)2S2O8 as initiator. The synthesized copolymer was characterized by using particle size, density, band gap, 1H NMR, TGA, and SEM measurements. The characterization results revealed the successful synthesis of the graft copolymer of PAni and CS. Electrokinetic properties and colloidal stabilities of PAni-g-CS dispersions were examined as a function of time, pH, electrolytes, various surfactants, and temperature by means of ?-potential measurements in polar (water) and non-polar (silicone oil) media. The ?-potential of PAni shifted to more positive region after grating with chitosan. In acidic medium, ?-potential of the copolymer was observed to increase up to +44mV. The presence of monovalent (Nacl) electrolyte had no impact on ?-potential of the copolymer dispersions whereas; divalent (BaCl2) and trivalent (AlCl3) electrolytes caused the ?-potentials of the dispersions to shift to more positive regions. The most effective surfactant on the ?-potential of the PAni-g-CS was determined to be sodium dodecyl sulfate, which reduced the value of ?-potential to -39mV. Elevated temperatures caused almost no change on the ?-potential of the copolymer dispersions. In non-aqueous media, ?-potential of PAni-g-CS was found to be in colloidally stable region. Further, PAni-g-CS was tested against Escherichia coli and showed an improved antibacterial activity when compared to that of pristine PAni and CS. © 2014 Elsevier B.V.