Surface structures of fluoropolymer, polyolefin and polyester films after modification by graft polymerization

Abstract

AbstractPristine and argon plasma pretreated polytetrafluoroethylene (PTFE), polystyrene (PS), high‐density polyethylene (HDPE) and poly(ethylene terrephthalate) (PET) films have been subjected to near‐UV light‐induced graft polymerization with water‐soluble acrylamide (AAm), the sodium salt of styrene sulfonic acid (NaSS), acrylic acid (AAc) and N,N‐dimethylaminoethylmethylacrylate (DMAEMA) monomers. The structure and composition at the substrate surface with grafted polymer were studied by angle‐resolved X‐ray photoelectron spectroscopy (XPS). In most cases, the density of surface grafting is enhanced by plasma pretreatment. For each polymer substrate with a substantial amount of grafting, the hydrophilic graft penetrates or becomes partially submerged beneath a thin surface layer of dense substrate chains. This stratified microstructure is consistent with the static secondary ion mass spectroscopy (SIMS) and Ar+beam depth profiling results. The two latter techniques also suggest that when the grafted polymer has a bulky substituent, there is less efficient penetration of the grafted polymer below the surface.