Grafting of Metal Nanoparticles with Specific Properties on Activated PET

Abstract

The aim of this work is grafting of metal nanoparticles (Ag, Au and Pt) onto plasma activated polyethylene terephthalate (PET) using polyethylene glycols (PEG). Colloidal nanoparticles were prepared by direct cathode sputtering of the metal into a solution of PEG:PEG-NH₂ and PEG:PEG-SH. Colloidal dispersions and grafted substrates were characterized by a number of analytical methods. The nature of the surface plasmon resonance band detected by UV-Vis analysis suggests a spherical shape of the nanoparticles, which corresponds well with transmission electron microscopy results. Size of the prepared nanoparticles ranged from 1.9 to 4.1 nm. Grafted substrates were more hydrophilic than pristine PET and their wettability did not depend much on the type of nanoparticles or stabilization agent. Nanoparticles grafted onto the PET surface were confirmed by X-ray photoelectron spectroscopy only in the case of the PEG-NH₂ stabilized nanoparticles. Due to its high affinity to metals, the thiol groups were bound to nanoparticles and did not form a bond with the activated PET surface. Atomic force microscopy showed an increased fragmentation of the PET surface after modification; spherical structures belonging to nanoparticles were also detected on the PET surface. The composites of metal nanoparticles with polymer substrates prepared in this way have a great potential in bioapplications (antibacterial coatings) or in electronics (data storage).