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 chemistry of polystyrene (PS) have been investigated using X-ray photoelectron spectroscopy (XPS). Attention was paid to sample storage conditions between treatment and analysis. At low treatment times alcohols and ketones are the only functionalities introduced into the plasma treated surface, offering the potential to tune the surface to these functionalities. At longer treatment times a wider range of functionalities were incorporated into the plasma treated surface. The stability of these surfaces, with respect to washing and ageing has been investigated. Surfaces washed with methanol exhibit stability up to a certain level of treatment (O/C ratio = 0.18), after which some washing away of the functionalities, present as low-molecular-weight material (LMWM), occurs. It is also shown, through contact angle measurements, that surfaces which are stable to rinsing are also stable with respect to ageing after treatment.