A multiple-stage activation of the catalytically inhomogeneous Cu(0) wire used in SET-LRP

Abstract

The surface of a Cu(0) wire used as a catalyst in the single electron-transfer living radical polymerization (SET-LRP) is inhomogeneous since it contains predominantly a combination of Cu(111) and Cu(100) faces of the face centered cubic unit cell of copper single crystals. The ratio between the areas of these two orientations is determined by the method of fabrication of the copper wire. The activity of these faces towards SET reactions is substrate dependent, and therefore, aside from the Cu₂O available on the surface, the ratio between the areas of these two crystal faces determines the catalytic activity of the wire. The inhomogeneous morphology of the Cu(0) wire is well-established and known in the scientific community of metallurgy but apparently is not known by the community of polymer chemistry. Here, we report a multiple-stage activation of the catalytically inhomogeneous Cu(0) wire used in SET-LRP by a combination of acetone washing, razor blade scratching, and either reduction or acid dissolution of the Cu₂O from the surface. An increase of Cu(0) wire activity up to 82% was accomplished via this new and simple activation method.