Deposition of polyaniline (PANI) monolayer onto indium tin oxide using Langmuir Blodgett (LB) technique

Polyaniline (PANI) monolayers can be formed and transferred onto indium tin oxide (ITO) glass using the Langmuir-Blodgett (LB) technique. Polyaniline emeraldine base (PANI-EB) was dissolved in methanol to observe the effect of polyaniline (PANI) solubility in alcohol. The results found that methanol provided a higher absorption rate for PANI-EB as compared to other alcohol solvents. The protonation process of PANI-EB to polyaniline salts (PANI-S) with the addition of doping substances, such as p-toluene sulfonic acid (PTSA), caused disruption to the back chain structure of PANI-EB. The elongation effect of the back chain of PANI allowed more reactions to occur and polarons to form. Polaron is important in imparting conductivity properties to materials. Factors such as pH and material concentration were found to influence the monolayer formed with pH 1 and 0.1M PANI concentration to be the study choice. The four-point probe analysis confirmed that PANI-S gave a lower resistance value than PANI-EB. Low resistivity exhibited high material conductivity because resistance is the inverse of conductivity. The formation of a PANI monolayer in a subphase with pH 1 caused the obtained resistance to be low due to the formation of polarons as a result of the reaction on the PANI back chain. Ultraviolet-Visible (UV-Vis) Spectroscopy and Fourier-Transform Infrared Spectroscopy (FTIR) analysis confirmed that there were peaks proving that PANI-S had formed through changes in absorption and the existence of new peaks. The particle size of the formed PANI-S was almost equal to the roughness value obtained, which was 1.50 nm. Based on the roughness and even distribution of polyaniline particles, it indirectly indicated that this is a suitable medium for the formation of monolayer.