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.

We have studied the adsorption of poly(styrene-b-2-vinylpyridine) block copolymers from a selective solvent onto a flat solid substrate, resulting in the formation of laterally ordered microdomains. We address the question whether the lateral domain structure is due to adsorption of entire micelles from the solution. Dynamic light scattering, atomic force microscopy, surface plasmon spectroscopy, and transmission electron microscopy were used to characterize the polymer solution, the adsorption process, and the resulting polymer layer, respectively. A quantitative comparison of the results obtained with different techniques strongly indicates direct adsorption of whole micelles onto a brush formed from free copolymer chains. Furthermore, the adsorption process is found to depend strongly on the velocity at which the samples are withdrawn from the solution.

We investigate the microscopic mechanisms responsible for microdomain alignment in block copolymer solutions exposed to an electric field. Using time-resolved synchrotron small-angle x-ray scattering, we reveal two distinct processes, i.e., grain boundary migration and rotation of entire grains, as the two dominant microscopic mechanisms. The former dominates in weakly segregating systems, while the latter is predominant in strongly segregated systems. The kinetics of the processes are followed as a function of polymer concentration and temperature and are correlated to the solution viscosity.

We have aligned the microdomains of a polystyrene-b-poly(2-hydroxyethyl methacrylate)-b-poly(methyl methacrylate) (PS-b-PHEMA-b-PMMA) triblock copolymer during preparation from solution by virtue of an external electric dc field (1.8 kV/mm). Bulk samples cast in the presence of an electric field exhibit lamellar microdomains highly oriented parallel to the electric field vector, as shown by small-angle X-ray scattering and transmission electron microscopy.

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