Study Optical and Structural Properties of Polyaniline films using Laser Irradiation

1. Abstract
In this study, a thin film of poly(aniline) was prepared by spin coating. The aim of this study was to evaluate the effect of pulsed Nd:YAG laser irradiation on the properties of poly(aniline) thin films at a wavelength of 532 nm, a repetition rate of 5 Hz, and pulse energies of of 0 ,150, 250, and 350 mJ for a fixed duration of 30 seconds. The optical, structural, and surface properties of the films were analyzed before and after irradiation using UV–Vis, AFM, FTIR, and XRD.The results showed a decrease in the energy gap from 2.35 eV to 2.2 eV, an increase in the absorption coefficient from 0.025 cm⁻¹ before irradiation to 0.033 cm⁻¹ after irradiation, improved polymer chain regularity, and increased chain length and charge carrier mobility. An increase in surface roughness and improvement in microstructure were also recorded, without significant thermal damage, and an increase in particle size from 26.0 nm before irradiation to 363.5 nm after irradiation. The results also indicate that pulsed laser at 532 nm provides measurable and controllable modification of the optical, structural, and surface properties of poly(aniline).