Surface modification of polyethylene terephthalate by plasma treatment

The surfaces of polyethylene terephthalate (PET) films have been treated by reactive gas (N2) plasma to determine the effects of low-energy ions on the surface modification of PET. The surface morphology of the PET was studied by the microhardness tester, atomic force microscope (AFM), FTIR spectroscopy as a function of fluence. DSC studies of pristine and irradiated samples are also reported here. It is observed that the hardness of the film increases significantly as the fluence increases. The bulk hardness of the film was measured at loads greater than 400mN. The increase follows a linear trend with fluence and has been explained in terms of cross-linking as observed from FTIR spectra. AFM shows that the average roughness (Ra) of the film surface decreases from 51-6nm after plasma treatment as fluence increases. DSC thermograms indicate changes in the melting properties of the system