Control of surface morphology by the interplay between phase separation and dewetting

By control of phase separation and dewetting of thin blend films of weakly incompatible polymers, particular surface patterns may be generated. These patterns cover a typical height scale from 0.3 nm to 300 nm and most prominent in-plane length scale from 0.1 μm to 100 μm. Characteristic features are holes, regular continuous structures, and drops of these sizes. In addition, conformal rough surfaces with a morphology dominated by one of the underlying substrates can be prepared. The surface morphology was investigated with scanning force microscopy (SFM), while the interface correlation was measured with diffuse X-ray scattering. Both methods together yield a topological description of the examined samples. Observed morphologies originated from phase separation of the thin blend film and from the dewetting of one blend component on top of a continuous film formed by the other component.