Preparation method effect on antibacterial properties of silver nanoparticles grafted onto polyethylene terephthalate

We report preparation of antibacterial polymer by grafting silver nanoparticles (Ag NPs) onto plasma activated polyethylene terephthalate (PET) via biphenyl-4,4'-dithiol interlayer . Used Ag NPs were synthesized by chemical (Ag NPCH), electrochemical (Ag NPE) and physical (Ag NPP) methods. Ag NPs dispersions were characterized by UV-Vis spectroscopy and transmission electron microscopy. Surface properties of PET were studied before and after each preparation step. Chemical composition was determined using X-ray photoelectron and energy dispersive X-ray spectroscopies. Morphology changes were observed on atomic force and scanning electron microscopes. Prepared substrates wettability and zeta potential were also investigated. PET samples before and after modifications were subjected to antibacterial test against Escherichia coli and Staphylococcus epidermidis. Ag NPP sample was the most effective even though analyses determined Ag NPE to be the smallest and their number on PET surface was the greatest. Far greater amount of Ag NPP was revealed to be in the volume than on top of PET sample. Good wettability also enabled bacterial solution to be in contact with larger area of Ag NPP sample surface. (authors)