Surface characterisation of ultraviolet-ozone treated PET using atomic force microscopy and X-ray photoelectron spectroscopy

The effects of ultraviolet-ozone (WO) oxidation of polyethyleneterephthalat e (PET) surfaces have been studied using atomic force microscopy and X-ray photoelectron spectroscopy. Surface oxygen increases from 26 at.% (untreate d) to 37 at.% for the most oxidised surfaces produced and an increase in me an surface toughness and grain size is also observed. The larger grains app ear to result from the formation of low molecular weight oxidised species b y PET chain scission at the eater group and the material formed is therefor e COOH/COOR rich. These species are mobile on the polymer surface and coale sce to form 200 nm grains which can be partially removed by water washing. The surface beneath is still rougher and more highly oxidised than untreate d PET but the increase in stable oxygen is due to the formation of COH/COR groups. (C) 1999 Published by Elsevier Science B.V. All rights reserved.