Surface characterization and antibacterial adhesion of poly (ethylene terephthalate) modified by acetylene plasma immersion ion implantation

This article reports a study of the behavior of bacterial adhesion to poly□ethylene terephthalate □(PET) which was modified by acetylene (C₂H₂) plasma immersion ion implantation (PIII). These surface-modified PETs were characterized by means of X-ray photoelectron spectroscopy (XPS) and attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). The capacities of Staphylococcus aureus (SA), Staphylococcus epidermidis (SE), Escherichia coli (EC), Pseudomonas aeruginosa (PA) and Candida albicans (CA) for adhesion to PETs were quantitatively determined by the plate counting and Gamma-ray counting of ¹²⁵I radio labeled bacteria in vitro. The results indicated that the capacities of five types of bacteria for adhesion to PETs were all suppressed by PIII treatment. The adhesion of SA on the surface of C₂H₂ PIII modifying was as less as 1/10 on the untreated PET surface. The capacities of SE on the modified surface were 25% comparing with that of the untreated surface. XPS and ATR-FTIR spectra showed amorphous carbon structure appeared after C₂H₂ plasma immersion ion implantation. This suggests that the improvement of bacterial adhesion to PET might come from the formation of an amorphous carbon phase by PIII. It is believed that the composition change of the modified surface layer would cause the improvement of the bacterial adhesion.