Surface modification of polymeric blends by nitrogen plasma implantation

The surfaces of polymeric blends of poly vinyl chloride and poly ethylene terephthalate have been treated by reactive (N2) gas plasma, in order to investigate the effects of low energy ions on the surface modification of polymeric blends. These effects were studied by microhardness testing, thermo-gravimetric analysis (TGA/DSC), optical microscopy, and atomic force microscopy (AFM), as a function of ion fluence. It was observed that hardness of the film increased significantly as fluence increased. The true bulk hardness of the film prevailed at loads greater than 400 mN. The increase in hardness may be attributed to cross-linking effect. The increase in hardness may be attributed due to cross-linking, an interpretation which is also corroborated by TGA thermograms. It was observed that thermal stability increases as fluence increases. The DSC (Differential Scaning Calorimetry) thermograms revealed a quite complex behavior in the temperature range 250–350 °C, where it was seen that with increase in fluence the DSC exotherm changed into the DSC endotherm. The optical micrographs clearly showed the surface roughness resulting from implantation. Atomic force microscopy (AFM) showed that the average roughness (Ra) of the film surface increased from 13.1 nm to 78.1 nm as fluence increased.