Surface-dependent growth of TEMPO polymers. It has been previously reported that TEMPO deposited by plasma polymerisation results in three distinct structures as shown in Figure ; the intact molecule (NO), damaged molecule (N), and a protonated structure (NH2 + ), which are each expected to behave differently against bacteria. Moreover, the orientation and intermolecular packing of TEMPO molecules within plasma polymer films are expected to depend on the surface, so an understanding of growth and its impact on topography (Figure -e), surface area, and chemistry are essential.