EFFECT OF LOW ENERGY AND HIGH CHARGE STATE OXYGEN AND NITROGEN ION BEAM IRRADIATION ON POLYMETHYL METHACRYLATE

Abstract

Surface modification of polymethyl methacrylate (PMMA) was done by using low energy and high charge state of Oxygen and Nitrogen ion implantation/irradiation facility using ECR ion source available at VECC Kolkata. Firstly, Oxygen ion beam of 7+ and 2+ charge states of energy 63 keV and doses I x 1016 and 1.4 x 1017 respectively were implanted on 10 x 10 mm2 of 1 mm thick sheet of PMMA. Secondly, high charge state (5+) of Oxygen and Nitrogen ion beam of 45 keV energy was implanted on the 10 x 10 mm2 of PMMA. The particle dose was varied between 1014 to 1017 ions/cm2. Optical responses, (absorbance, reflectance and transmittance), dielectric responses (dielectric response, dielectric loss) and morphological studies by FE-SEM were employed to investigate structure and properties of the as-implanted PMMA samples. The dielectric constant of implanted PMMA as a function of applied frequency of electric field was found to be independent of high charge state ion, but it depends on the implanted dose. The dielectric loss of these samples varied in different frequency range for different high charge state ions. The absorbance of O'+ and 02+ implanted PMMA samples was higher in UV-Vis range and show charge state dependency. The absorbance of 05 " implanted PMMA samples was higher as compared to the N5+ implanted PMMA. Further optical absorbance for N5+ and 05+ implanted PMMA were high for high dose. The diffuse reflectivity (DR) of O5+ implanted PMMA samples were about two times higher than N5+ implanted PMMA. The DR of O5+ and N5+ implanted PMMA was found to be dose dependent. The surface morphology of 02+ and O7+ implanted PMMA samples had shrunken and ripples of different wavelength on the surface were formed. However, such ripples were not observed in the PMMA sample implanted with 45 keV 0 and N beams of 5+ charge state.