The Effect of Solution Concentration and Deposition Time on Viscoelasticity and Morphology of Polyaniline Coating

Abstract

As one of the most studied conductive polymers, polyaniline (PANi) has a variety of applications, one of which is an active gas sensor, due to the presence of amine and imine groups in PANi that can easily react with gas. Quartz crystal microbalance (QCM) is a piezoelectric sensor with the working principle of frequency changes as a result of changes in mass on its surface. As an active gas sensor material on the QCM substrate, PANi must be deposited in the form of a thin layer. A good quality of thin film is if the film does not give loading the effect on QCM and has a homogeneous morphology. This research has succeeded in depositing PANi thin films by surface polymerization method by varying the parameters of PANi solution concentration and deposition time. Deposition parameters that are varied can be seen its effect on the viscoelasticity and morphology of PANi thin film formed. The viscoelasticity of the thin film was interpreted from the measurement of the thin layer impedance using an impedance analyser, while the morphology of the thin film was characterized using SEM. From the results of this study it was found that with the surface polymerization method, the PANi thin layer impedance value changes with the deposition time which is getting longer, but the change in impedance value is not significant and does not give a loading effect on QCM. At the same deposition time with different solution concentrations, the impedance value of the formed layer also does not give a loading effect on QCM. Although it has successfully deposited PANi with a surface polymerization method, the morphology of the PANi film formed is not yet homogeneous, as seen from the formation of PANi agglomeration on the QCM surface.

The Effects of Potentiostat Scan Rate Variation on Impedance Value, Topography, and Morphology of the Polyaniline Thin Film

“…In this research, variations of scan rates and HCl concentrations were conducted, the impedance values for all samples are still below 100 Ω, which does not have a damping effect on QCM. The result of PANi thin film deposition with this potentiostat method is better than that of previous researchers in the spin coating method [17] and surface polymerization [18].…”

“…The frequency shift is affected by the addition of dopant concentrations and differences in scan rates [18]. It appears from the impedance curve.…”

“…The impedance value in the HCl 3 sample deposited at the 30 mV/s scan rate also high value (Figure 3), but does not show damping effects on QCM. Saurbrey's equation explains that the more PANi mass deposited on the QCM surface, the more significant the frequency change of QCM [18]. Excessive frequency shifting will cause a damping effect so that the sensor cannot function properly.…”

“…There are several deposition methods of PANi layer which have done by many previous researchers, including that reported by Rahayu et al [18], which used the surface polymerization method. Rahayu et al [18] reported that the concentration and deposition time of PANi did not affect the damping of QCM despite powder agglomeration PANi which deposited above the QCM.…”

“…There are several deposition methods of PANi layer which have done by many previous researchers, including that reported by Rahayu et al [18], which used the surface polymerization method. Rahayu et al [18] reported that the concentration and deposition time of PANi did not affect the damping of QCM despite powder agglomeration PANi which deposited above the QCM. Another study also reported by Putri et al [17], who used the spin coating method, showing that the deposition carried out at low rotational speeds could affect the damping effect on QCM due to the PANi agglomeration.…”