Improve the structure and optical surface properties of LDPE by ion bombardment technique

Abstract

Nowadays, ion bombardment became one of the powerful methods usually carried out to modify the surface characteristics of the polymeric materials. In this work, low-density polyethylene (LDPE) polymer samples were bombarded with different fluences by 130 keV He-ion beam. The X-ray diffraction patterns of the untreated sample as well as those exposed to He-ion beam revealed the crystalline nature of the samples. The effects of He-ion beam bombardment on the structural parameters e.g. crystal size, dislocation density, inter-chain separation, micro-strain, and distortion were studied. The optical absorption coefficient and refractive index were calculated as a function of He-ion beam fluences. The optical energy gap and Urbach energy were also evaluated. Wemple-DiDomenico effective single oscillator and Sellmeier models were both used to describe adequately the refractive index dispersion in the low absorption region. Graphical representation of the complex dielectric constant and dissipation factor was also presented. A significant modification in the structural and optical parameters was obtained by ion bombardment technique.