Determination of the optical properties of ion beam modified polymers

Polyetheretherketone samples were irradiated with 50 kV N+, 10 kV Sn+;++ and 45 kV Sn+;++ ions at various doses ranging from 1 x 10^14 to 1 x 10^17 ions/cm^2. Modification of the optical properties of the polymer samples were investigated using Ultraviolet-Visible-Near Infra-red spectroscopy. Analysis of the optical spectroscopy suggested an increase in reflection and absorption of the samples after ion implantation. An equation that determines a wave- length dependant optical absorption coefficient was then developed using theoretical modelling methods. This optical absorption coefficient equation was then applied to the optical spectroscopy measurements. The equation was compared to existing modelled absorption coefficient equations of ion implanted polymers. The proposed model calculated an absorption coefficient over the highly absorptive modified region of the sample as opposed to most existing models that calculate this over the entire sample. A significant increase in the absorption coefficient of the proposed model was observed compared to existing models. All calculated absorption coefficients were then used to produce Tauc plots that estimate the optical band gap of these modified materials. Significant differences in optical band gap were also observed between the proposed model and existing models. These results and conclusions are discussed along with recommendations on which future research should be taken to validate the results