Effect of Evaporation Deposition Time on Thickness and Impedance Value of Polyaniline Layers

Abstract

Abstract Quartz Crystal Microbalance (QCM) works by using the principle of frequency shifting in quartz crystals due to mass deposition on the surface of the crystals. QCM sensors can be applied as chemical sensors and gas sensors. To increase its sensitivity and selectivity, QCM must be coated with active ingredients, one of which is Polyaniline (Pani). There are several methods for the Pani layer deposition above QCM. In this study, the evaporative deposition method was carried out. The purpose of this study was to analyse the effect of deposition time on the thickness and impedance value of the Pani layer. Before being coated by Pani, QCM was given a polystyrene coating to increase its adhesion. The variation of deposition time used was 10; 15; 30 and 60 seconds. The characterization carried out was measured the impedance of the layer by using an impedance analyser, observing the layer morphology by using an optical microscope, and determining the thickness of the layer using the Saurbrey equation approach. The results showed that the longer the deposition time caused the Pani layer to be deposited thicker and had a more even morphology. The layer impedance value was also getting bigger. The maximum thickness obtained at the deposition time of 60 seconds was 32.21 μm with a layer impedance value of 891.57 Ω. With a huge impedance value, the Pani layer provides a substantial damping effect on QCM.