Oxygen plasma irradiation-induced surface modifications on HDPE and PET polymeric films

Nowadays, plasma treatments are one of the powerful techniques usually accomplished to change the surface characteristics of polymeric films. This study presents the influence of oxygen plasma irradiation on the structural and the optical properties of high-density polyethylene (HDPE) and polyethylene terephthalate (PET) films that will be used in optoelectronic devices. The films were irradiated with an oxygen plasma for duration of 3, 4.5, and 6 min. The surface structure of the films was investigated utilizing X-ray diffraction (XRD). For an irradiation time of 6 min, the crystallite size changes from 13.9 to 19.7 nm and from 5.7 to 6.5 nm for pristine HDPE and PET, respectively. The UV–Vis optical absorption spectrum demonstrates a slight shift in the absorption edge towards the visible region caused by the oxygen irradiation time for both the HDPE and the PET films. Increasing the irradiation time leads to a slight decrease in the optical energy band gap Eg and to an improvement in the carbon cluster number N. The results show clear improvements in the optical properties of HDPE and PET due to plasma irradiation that make them good candidates for use in optoelectronics applications.