Solvent Effect on Viscoelastic Behaviour and Morphology of Polyaniline Coating at QCM Sensor

Abstract

The effect of different solvents and solution concentration on viscoelastic behaviour and morphology of polyaniline (PANi) coating was investigated in this study. The PANi coating on a QCM sensor was created by spin coating with various solvents, such as NMP, m-cresol, and DMF with varying concentrations of 1-4% by weight of PANi. The viscoelastic behaviour was observed by impedance analyser and morphology of the PANi coating was observed via optical microscope and SEM/EDX. The viscoelasticity was measured to determine whether the coating produces an acoustic load (loading effect). The observations showed that the different solvents give a different effect on the impedance value of the PANi coating. With m-cresol solvent, the impedance value in the series resonant frequency was so large, indicating the PANi coating was not rigid and produce a loading effect on QCM sensor. From morphology observation showed that homogeneity of the polyaniline coating is still poor. There is an agglomeration of polyaniline powder which is insoluble in the solvent used. From the viscoelastic properties of the coating, the optimum value was obtained in PANi coating with NMP solvent.