Ar-O₂ Plasma-Induced Grafting of Quaternary Ammonium on Polyvinyl Chloride Surface to Improve its Antimicrobial Properties

In this paper, a novel method is presented to enhance the antimicrobial properties of polyvinyl chloride (PVC) via plasma-induced grafting of quaternary ammonium (QA). The results show that the content of oxygen-containing functional groups on PVC surface is significantly increased after Ar-O₂ plasma treatment, beneficially enhancing the thickness and adhesion of QA coating. Plasma treatment time critically affects the morphology of PVC surface, which is closely related to the number, depth and diameter of pit on the surface. With the increase of pits size, the PVC surface forms ridge-like protrusions. The coating formed by grafting QA maintains the morphology characteristics of plasma-treated PVC surface. Results of antibacterial test show that specimens have the best antibacterial activity when there are a high and sharp ridge-like structure of QA coating on the plasma-treated PVC surface.