Water uptake in polyethylene terephthalate irradiated by medium energy O+ and Au+ ions

ABSTRACTThe effect of the ion irradiation on the water uptake in polyethylene terephthalate (PET) was examined. The PET samples were irradiated with MeV Au+ and O+ ions to different fluencies and then exposed to a water solution of LiCl, serving as a marker, for one month. After drying and removing of excessive surface LiCl the depth profiles of incorporated Li were measured by nondestructive neutron depth profiling (NDP). The ion species of different mass were chosen in order to examine the role of different mechanisms of energy transfer, nuclear and electronic ones, in PET modification. It was found that the ion irradiation to the fluencies below 1012 cm-2 has no visible effect on the water uptake into PET. For higher fluencies, a noticeable water penetration was detected and for the fluencies above 3.0 × 1013 cm-2 a water-soaked region was formed from the sample surface up to the depth roughly correlated with the ion projected range.