title: Electric-field-induced lamellar to hexagonally perforated lamellar transition in diblock copolymer thin films: kinetic pathways.
abstract: Symmetric block-copolymers, hitherto, are well known to evolve into parallel, perpendicular and mixed lamellar morphologies under the concomitant influence of an electric field and substrate affinity. In the present work, we show that an additional imposed confinement can effectuate a novel parallel lamellar to hexagonally perforated lamellar (HPL) transition in monolayer and bilayer films. Three dimensional numerical studies are performed using the Ohta-Kawasaki functional, complemented with an exact solution of Maxwell's equation. HPL is shown to stabilize at large substrate affinity in a narrow region of the phase diagram between parallel and perpendicular lamellar transitions in ultra-thin films. Additionally, we also identify perforated lamellae as intermediate structures during parallel-to-perpendicular lamellar transition. A systematic analysis using Minkowski functionals yields deeper insights into the associated kinetic pathways.
authors.affiliation: Institute of Materials and Processes, Karlsruhe University of Applied Sciences, Moltkestr. 30, 76133, Karlsruhe, Germany. muar0002@hs-karlsruhe.de and Institute of Applied Materials - Computational Materials Science, Karlsruhe Institute of Technology, Haid-und-Neu str. 7, 76131, Karlsruhe, Germany.
authors.forename: Arnab
authors.identifier: http://orcid.org/0000-0002-6783-8225
authors.initials: A
authors.lastname: Mukherjee
authors.affiliation: Institute of Applied Materials - Computational Materials Science, Karlsruhe Institute of Technology, Haid-und-Neu str. 7, 76131, Karlsruhe, Germany.
authors.forename: Kumar
authors.identifier: http://orcid.org/0000-0001-5283-5139
authors.initials: K
authors.lastname: Ankit
authors.affiliation: Institute of Applied Materials - Computational Materials Science, Karlsruhe Institute of Technology, Haid-und-Neu str. 7, 76131, Karlsruhe, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Reiter
authors.affiliation: Institute of Materials and Processes, Karlsruhe University of Applied Sciences, Moltkestr. 30, 76133, Karlsruhe, Germany. muar0002@hs-karlsruhe.de and Institute of Applied Materials - Computational Materials Science, Karlsruhe Institute of Technology, Haid-und-Neu str. 7, 76131, Karlsruhe, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Selzer
authors.affiliation: Institute of Materials and Processes, Karlsruhe University of Applied Sciences, Moltkestr. 30, 76133, Karlsruhe, Germany. muar0002@hs-karlsruhe.de and Institute of Applied Materials - Computational Materials Science, Karlsruhe Institute of Technology, Haid-und-Neu str. 7, 76131, Karlsruhe, Germany.
authors.forename: Britta
authors.initials: B
authors.lastname: Nestler