Controlled phase separation in a polymer film, with subsequent morphology rearrangement on the micro-scale, provides novel perspectives in smart materials. Based on our experience on supramolecularly compatibilised polymer blends consisting of polystyrene and poly(butyl methacrylate), we demonstrate here physical segregation of the blend in the solid state by the application of an electrochemical stimulus. The thereby occurring changes in film morphology, namely the appearance of voids and grains, have been characterised by atomic force microscopy in spin coated and in Langmuir-Schaefer deposited films.