New insights into corona discharge surface ionization of polyethylene terephthalate via a combined computational and experimental assessment

The aim of the present work is to demonstrate the influence of corona discharge ionization on chemical and physical properties of polyethylene terephthalate (PET) fibers using computational and experimental studies. In the computational section, the vibrational frequencies of proposed models for PET before and after corona discharge treatment were predicted in the liquid phase at both the B3LYP/6-31G/COSMO and B3PW91/6-31G/COSMO level of theories using the harmonic approximation. When compared to B3LYP, the frequencies obtained for the B3PW91 show a better linear correlation with the experimental data. Furthermore, experimental studies were carried out by the use of Fourier transform infrared spectroscopy (FTIR), X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), and reflectance spectroscopy (RS). Experimental evidence indicated that the corona discharge modifies the surface of fibers and also increases the reactivity of PET toward cationic dyes. Our combined computational and experimental parametric study clearly confirms that the changes occurred on the PET surface due to corona discharge ionization.