Dresden 2003 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

CPP: Chemische Physik und Polymerphysik

CPP 22: POSTER C

CPP 22.44: Poster

Donnerstag, 27. März 2003, 12:00–14:00, ZEU/250

Influence of molecular architecture on the phase behavior in thin films of cylinder forming block copolymers — •L. A. Tsarkova, A. Knoll, and R. Magerle — Physikalische Chemie II, Universität Bayreuth, 95440 Bayreuth

We report on experiments with thin films of polystyrene-block-polybutadiene diblock copolymer melts and concentrated solutions in chloroform. During annealing, either by heating (melts) or by exposing the films at room temperature to a well controlled chloroform vapor (solutions), the films form terraces with energetically favored film thickness. With TappingMode scanning force microscopy we study the resulting microdomain structures as function of film thickness, polymer concentration, and annealing temperature. The general phase behavior of melts as well as of concentrated solutions of diblock copolymers is found to be very similar to that of concentrated solutions of triblock copolymers of twice the diblock copolymer length [A. Knoll et al., Phys. Rev. Lett. 89, 035501 (2002)]. This confirms the universality of the reported phenomena. In addition to the disordered phase and the perforated lamella phase, the studied diblock copolymers form also the lamella phase as predicted by MesoDyn computer simulations. Details, however, such as the position of phase boundaries and the structure of steps between terraces, are different to triblock copolymers.