A comparative study of the surface activation of polyamides using an air dielectric barrier discharge

Nylon-6 and Nylon-12 films were modified in an air dielectric barrier discharge (DBD) to understand the contributions of parent polymers structure to the resulting surface modification. The modified polyamide films were characterised by contact angle measurement, XPS, SIMS and ATR-FTIR techniques. For DBD treatment under similar experimental conditions, the resultant surface hydrophilic modification of the Nylon-12 film (based on contact angle measurement) was slightly greater than that of the Nylon-6 film. In contrast, the oxygenation of the surface achieved by the DBD treatment of the Nylon-6 film (in terms of XPS derived O/C ratios) was significantly greater than that of the Nylon-12 film. Post-processing storage study after one-month show recovery of modifications (in terms of the contact angle and O/C ratios) induced by DBD treatment. The recovery of modified surface was relatively marked for the Nylon-6 film. On the basis of SIMS investigations of the Nylon-12 film, formation of low molecular weight oxidised material at the treated surface after DBD treatment and their subsequent decay with extended storage is arguably responsible for the greater recovery from modification. On the other hand, relatively stable hydrophilic modification of the Nylon-12 film was associated with the chemically bonded surface oxygen formed during DBD treatment.