Macromol. Rapid Commun. 5/2007

Abstract

Cover: The article by Potemkin and coworkers provides free-energy considerations to explain the molar mass dependent morphology of lamellar diblock copolymer thin films of poly(styrene-b-butadiene). Atomic force microscopy (AFM) and grazing-incidence small-angle scattering (GISAXS) data were instrumental to establish the lamellar orientation as a function of the interaction parameter xN and the ratio of film thickness over lamellar thickness D red . The relevant free-energy contributions are discussed that determine the boundary between the observed orientational phases. Further details can be found in the article by

Probing the Self-Organization Kinetics in Block Copolymer Thin Films

“…The scattering image of the dried film was again different from earlier images: The film had regained the equilibrium parallel lamellar orientation [8]. The overall scattering intensity was stronger than during the vapor treatment, however, the radial width of the lamellar signal remained broad, as opposed to the much sharper peak width obtained for this lamellar orientation at low swelling ratio.…”

“…This procedure yields highly oriented block copolymer films, e.g. parallel or perpendicular lamellae [6][7][8], standing or lying cylinders [3,4,9,10], or monolayers of spheres [10].…”

Structural Rearrangements in a Lamellar Diblock Copolymer Thin Film during Treatment with Saturated Solvent Vapor

“…In the bulk, the diblock copolymer morphology is controlled by the overall degree of polymerization, N , the volume fraction of one of the blocks, f , and the Flory-Huggins segment-segment interaction parameter χ between the two blocks. For thin films, confinement effects are important as well,7 which are reflected in the interfacial tensions and additional entropic contributions to the free energy at the air-polymer and the polymer-substrate interface 8-11. These parameters together with the roughness of the substrate12 and the molar mass of the copolymer13 determine the degree of preferential orientation of domains in the block copolymer film with regard to the substrate.…”

Synthesis, characterization, and electroluminescence properties of poly(fluorenevinylene benzobisthiazoles)

“…Powder diffraction patterns of thin films were obtained using a Riguku Ultima IV X‐Ray diffractometer equipped with an MPA‐U4 multipurpose Eulerian cradle and 1.76 kW Cu Kα radiation. Samples were first scanned from 0.05 to 0.501° 2θ using parallel‐beam optics to determine the critical angle of the films 20. The incident angles of the X‐ray beam for the diffraction studies were chosen to be at a value slightly above the external critical reflection for the polymer films.…”

“…Samples were first scanned from 0.05 to 0.501 2h using parallel-beam optics to determine the critical angle of the films. 20 The incident angles of the X-ray beam for the diffraction studies were chosen to be at a value slightly above the external critical reflection for the polymer films. Fluorescence lifetime measurements were performed using the timecorrelated-single-photon counting method.…”