Plasma deposition of thin fluorocarbon films for increased membrane hemocompatibility

Plasma polymerization of gases present in a low temperature plasma is a “clean” technique that is particularly well suited for biomedical material processing. This paper presents the first results of a project which studies the possibilities offered by this technique to prepare commercial lowcost membranes with the required bio- and hemocompatibility to be implanted in an organism. The deposition on polysulfone of films from a plasma containing a mixture of ethylene oxide and perfluorohexane in order to obtain very hydrophobic, less hydrophobic and intermediate coatings was studied. Results obtained by adding hydrogen to perfluorohexane are also discussed. The deposition of a thin coating from a perfluorohexane and hydrogen plasma was studied in order to optimize the surface properties of the treated membranes without affecting their filtering properties. The treated substrates have been characterized by measuring mass variations, by surface profilometry and contact angle techniques as well as by scanning electron microscopy and electron spectroscopy for chemical analysis.