Hydrophilic surface modification of poly(vinyl chloride) film and tubing using physisorbed free radical grafting technique

The grafting of hydrophilic monomers from the surface of PVC films and complex geometries, such as tubing, was executed by a novel two-step process: physisorption of a hydrophobic free radical initiator onto a polymer surface followed by radical polymerization with hydrophilic monomers. The key step is creating a hydrophobic/hydrophilic diffusional barrier that promotes radical generation upon heating at the polymer surface. Transmission infrared spectroscopy, X-ray photoelectron spectroscopy, surface wettability and capillary rise, gravimetric analysis, UV-vis spectroscopy and gel permeation chromatography were utilized to prove successful covalent grafting of poly(hydroxyethylmethacrylate), poly(dimethylacrylamide), poly(hydroxyethylacrylate), poly(dimethylaminoethylmethacrylate), poly(acrylic acid), and poly(4-vinyl pyridine).