Patent ID: 9095834
Filing Date: 2015-08-04
Classification: B01J,H01J,Y02P

Abstract:
1. A method of modifying a substrate using a plasma, comprising: providing a first electrode and a second electrode; arranging the substrate such that only a portion of the substrate is between the electrodes; rotating either the substrate or at least one of the electrodes about an axis so as to cause different portions of said substrate to pass between the electrodes during said rotation; and supplying a voltage to at least one of the electrodes so as to create a plasma discharge between the electrodes which contacts at least said portions of the substrate that pass between the electrodes; wherein the second electrode is a wire electrode, a tubular electrode or a rod electrode that extends along the first electrode and in a direction radially outward from said axis of rotation; wherein the electrodes and the substrate are arranged such that said rotating causes the speed of transit of the substrate portion between the electrodes to vary in a radial direction away from the axis of rotation; wherein said electrodes are arranged and said rotation occurs such that an area of the substrate that is further from the axis of rotation passes between the electrodes and is modified by the plasma discharge at lower rate than an area of the substrate that is closer to the axis of rotation and which passes between the electrodes; wherein the plasma modifies the substrate by one or more of the following processes: modifying the substrate surface to include chemical functionalities; depositing monomers or oligomers on the surface; grafting monomers or oligomers on the surface; or polymerising monomers or oligomers on the surface; and wherein the plasma treatment alters the surface chemistry of the substrate surface by different amounts in different areas of the substrate.