Abstract
The correlation between plasma optical properties and the treated polyethylene terephthalate (PET) surface characteristics have been studied at various Ar flow rate. The rotational T-rot and vibrational T-vib temperatures of APPJ were determined from SPS emission band. The pristine and plasma-treated PET surfaces were characterized by several techniques including X-ray photoelectrons spectroscopy (XPS), Raman spectroscopy, contact angle (CA), and atomic force microscope (AFM). The CA decreased rapidly in the flow rate range 1-3 L/min and weakly dependent as flow rate > 3 L/min. XPS results showed that C 1s % of plasma-treated PET surfaces decreases and has a minimum for samples treated at 3-4 L/min, while O 1s has a maximum at the same flow rate range. The carbon C 1s peak of pristine and plasma treated PET samples resolved into five subcomponents: C-C, C-O, C=O, O-C=O, and pi-pi bonds with variable percentage ratio accordance to the plasma gas flow rate. Raman data revealed a partial loss in the crystallinity of the treated PET samples and also confirm the incremental of C-O band at Ar flow rate of 3 L/min. AFM images showed that the surface roughness of treated PET films increases as Ar flow rate increases.