PLASMA TREATMENT OF POLYMERS - EFFECTS OF ENERGY-TRANSFER FROM AN ARGON PLASMA AND POST-PLASMA STORAGE ON THE SURFACE-CHEMISTRY OF POLYSTYRENE

The effects of a radio-frequency (RF) argon plasma on the surface chem istry of polystyrene (PS) have been investigated using X-ray photoelec tron spectroscopy (XPS). Attention was paid to sample storage conditio ns between treatment and analysis. At low treatment times alcohols and ketones are the only functionalities introduced into the plasma treat ed surface, offering the potential to tune the surface to these functi onalities. At longer treatment times a wider range of functionalities were incorporated into the plasma treated surface. The stability of th ese surfaces, with respect to washing and ageing has been investigated . Surfaces washed with methanol exhibit stability up to a certain leve l of treatment (O/C ratio = 0.18), after which some washing away of th e functionalities, present as low-molecular-weight material (LMWM), oc curs. It is also shown, through contact angle measurements, that surfa ces which are stable to rinsing are also stable with respect to ageing after treatment.