We have studied the microdomain morphology of thin ABC triblock copolymer films supported by a solid substrate. The films were exposed to various solvent vapors, and the effect of the solvent removal speed on the resulting morphologies is investigated. Slow solvent extraction rates lead to a parallel alignment of lamellar microphases within the plane of the film. On fast drying, a perpendicular orientation of the lamellae is found. In the case of block copolymer samples with a highly anisotropic macroscopic shape, the microdomains can be aligned over large lateral areas. The results are discussed in view of the mechanical strain fields present during the drying process.

We combine scanning force microscopy experiments with ex-situ swelling in different solvent vapors to investigate the microdomain structure of a thin ABC triblock copolymer film (poly(styrene-b-2-vinylpyridine-b-tert-butyl methacrylate)). We demonstrate that short treatment in a selective vapor and subsequent drying lead to characteristic changes in the surface morphology. The use of different solvents then allows to unambiguously identify the different phases present at the surface. This approach is established studying polymer blend and diblock copolymer thin films of known morphology. It is then applied to the a priori unknown morphology of the ABC triblock copolymer thin film. The results indicate a laterally microphase-separated polymer surface in agreement with recent theoretical considerations. The conclusions are corroborated by XPS measurements monitoring the average surface composition of the copolymer films.

We have studied the thin film morphologies of polystyrene-b-poly(2-vinylpyridine) diblock copolymers and polystyrene-b-poly(2-vinylpyridine)-b-poly(tert-butyl methacrylate) triblock copolymers after “annealing” in the vapor of different solvents. We find distinct differences in the resulting thin film morphologies. The differences are explained qualitatively on the basis of concentration-dependent Flory−Huggins interaction parameters of the different components.

We investigate the microdomain orientation kinetics of concentrated block copolymer solutions exposed to a dc electric field by time-resolved synchrotron small-angle X-ray scattering. As a model system, we use a lamellar polystyrene-b-polyisoprene block copolymer dissolved in toluene. Our results indicate two different microscopic mechanisms, i.e., nucleation and growth of domains and grain rotation. The former dominates close to the order-disorder transition, while the latter prevails under more strongly segregated conditions. This conclusion is corroborated by computer simulations based on dynamic density functional theory. The orientation kinetics follows a single-exponential behavior with characteristic time constants varying from a few seconds to some minutes depending on polymer concentration, temperature, and electric field strength. From the experimental results we deduce optimum conditions for the preparation of highly anisotropic bulk polymer samples via solvent casting in the presence of an electric field.