Regensburg 2010 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 31: Poster: Polymer Dynamics
CPP 31.11: Poster
Mittwoch, 24. März 2010, 17:30–19:00, Poster C
Electric Field Induced Alterations of Block Copolymer Domain Spacings — •Christian W. Pester, Heiko G. Schoberth, and Alexander Böker — Lehrstuhl für Makromolekulare Materialien und Oberflächen and DWI an der RWTH
We investigate the effects of direct current electric fields on a concentrated lamellar polystyrene-b-polyisoprene (SI) block copolymer system in toluene by using synchrotron small angle X-ray scattering (SAXS). Measurements were performed in a home-built capacitor with parallel gold electrode geometry at the European Synchrotron Radiation Facility (ESRF) in Grenoble, France. As previously shown, electric fields are able to align bulk copolymer morphologies, whereas increasing field strengths lead to both sub-nanometer size variations of SI block copolymer lamellae in the phase separated regime, as well as to alteration of correlation hole scattering lengths in the mixed state. In this work we were able to show, that the sensitivity (ΔL/E) of the SI copolymer chains towards the electric field varies strongly with the temperature of the system, and a shift in the order-disorder transition temperature regime occurs. Furthermore, non-Gaussian behavior of SI-chains in the phase separated regime was discovered, as various field strengths deform the present lamellae to different degrees. Above TODT Gaussian behavior is adopted, and, due to the lack of morphology based pre-alignment of the polymer chains, their sensitivity towards the electric field increases. In this state chains themselves can be influenced and deformed away from their Gaussian state.