Using quasi-in-situ scanning force microscopy we study the details of nanopattern alignment in ABC terblock copolymer thin films in the presence of an in-plane electric field. Because of the surface interactions and electric field the lamellae are oriented both perpendicular to the plane of the film and parallel to the electric field. We identified two distinct defect types which govern the orientation mechanism. Ring-like (tori) and open-end defects dominate at the early stage of the orientation process, while mainly classic topological defects (disclinations and dislocations) are involved in long-range ordering at the late stages. Comparison of the time evolution of the defect density with the evolution of the orientational order parameter suggests that tori-defects are essential for the effective reorientation. Further, the quasi-in-situ SFM imaging allowed us to elucidate the influence of the electric field strength on the propagation velocity of the topological defects.

We study the wetting behaviour of thin polystyrene (PS) films on regularly corrugated silicon substrates. Below a critical film thickness the PS films are unstable and dewet the substrates. The dewetting process leads to the formation of nanoscopic PS channels filling the grooves of the corrugated substrates. Films thicker than the critical thickness appear stable and follow the underlying corrugation pattern. The critical thickness is found to scale with the radius of gyration of the unperturbed polymer chains.

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The near-surface rheology of polystyrene films at temperatures around T g was probed via the decay kinetics of shallow, nanoscale surface corrugation gratings. The gratings were created via hot embossing with a stepped silicon template. The wavelengths are distributed in a range between 25 and 60 nm and have a modulation depth of about 0.8 nm peak-to-peak. Upon heating, one observes a surface tension-driven decay of the surface corrugation at temperatures more than 30 deg below the bulk T g. Such a fast decay is unexpected and indicates a strongly lowered glass temperature near the surface.