Reactivity of surface groups attached on a plasma treated poly(propylene) film. Application to a new concept of a chelating membrane

The goal of the present work is the synthesis of a new chelating membrane f rom a trivial material, such as poly(propylene), through the fixation of th e chelating groups after a cold plasma irradiation. The cold plasma treatment compared to the electron beam irradiation is less degrading since only a few layers are affected. It leads to a surface bear ing two types of reactive species: radicals able to initiate a post-graftin g reaction of any kind of vinyl monomer and new surface functional groups - depending on the chemical nature of the cold plasma - able to react with a chelating molecule. So the modulation of the plasma conditions and the cho ice of the attached chelating groups onto the material can control the chel ating capacity of such irradiated material. The nitrogen plasma modificatio n of poly(propylene) (PP) lends to a weakly cross-linked and slightly degra ded surface bearing alkyl radicals and amino groups in various densities de pending on plasma conditions. After the plasma irradiation, N-acryloylglyci ne (NAG) and diethylenetriamine-pentaacetic acid (DTPA) possessing specific chelating properties are grafted successfully onto the PP surface in diffe rent ways. All the grafted films present an important selectivity towards s ilver ions and consequently towards soft metallic ions, too. The ion capaci ty of NAG grafted films remains higher than with DTPA whatever the density of amino groups attached on the surface is.