perfluorocarbon polymer - based matrices are coated with a hydrophilic polymer for use in bioaffinity separations . coating is carried out by dispersing porous particles of inert perfluorocarbon polymer in a water - miscible organic solvent such as acetone or tetrafydrofuran to wet surfaces of the particles , forming a dispersion of the wetted particles in an aqueous solution of hydrophilic polymer such as poly containing a plurality of hydroxyl groups , at least one being at an end of a polymer chain , to adsorb the hydrophilic polymer onto the wetted surfaces of the particles , admixing a homobifunctional cross - linking agent such as glutaraldehyde with the particles to cross - link the hydrophilic polymer , activating hydroxyl groups on the surface of the cross - linked hydrophilic polymer and covalently bonding a ligand or ligand binder to the activated hydroxyl groups .