Electric field effects on alignment of lamellar structures in diblock copolymer thin films studied by neutron scattering [Elektronische Ressource] / vorgelegt von Xiuli Jiang

Electric Field E ects on Alignment of LamellarStructures in Diblock Copolymer Thin FilmsStudied by Neutron ScatteringDissertationzur Erlangung des akademischen Gradesdoctor rerum naturalium(Dr. rer. nat.)genehmigt durchdie Naturwissenschaftliche Fakult at IIInstitut fur Physikder Martin-Luther-Universit atHalle-Wittenbergvorgelegt vonFrau M. Sc. Xiuli Jianggeboren am 15.05.1977 in Jilin, ChinaGutachterin / Gutachter:1. Prof. Dr. Thomas Thurn-Albrecht2. Prof. Dr. Bernd Stuhn3. Prof. Dr. Christine M. PapadakisHalle (Saale), Oktober 2006Verteidigungsdatum: 07.12.2006urn:nbn:de:gbv:3-000011227[http://nbn-resolving.de/urn/resolver.pl?urn=nbn%3Ade%3Agbv%3A3-000011227]AbstractWe investigated the lamellar orientation in thin lms of a diblock copolymer P(S-b-MMA), under competing e ects of surface interactions and an electric eld appliedperpendicular to the substrate. The e ects tend to align the lamellae parallelto the substrate while the electric eld tends to align the lamellae perpendicular tothe substrate. Using neutron re ectivity, neutron di use scattering, and neutron small-angle scattering, we achieved a quantitative analysis of the internal structure of the lms. Film thickness was found to play a non-trivial role in determining the structure ofthe lms. A complete alignment by the surface e ects was observed in the thinner lmsby annealing. The parallel orientation remains stable even if an electric eld as strongas 40 V/„m is applied.