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Proceedings Paper

Effects of electric fields on the photonic crystal formation from block copolymers
Author(s): Taekun Lee; Jin-wook Ju; Won Ryoo
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Paper Abstract

Effects of electric fields on the self-assembly of block copolymers have been investigated for thin films of polystyrene-bpoly( 2-vinyl pyridine); PS-b-P2VP, 52 kg/mol-b-57 kg/mol and 133 kg/mol-b-132 kg/mol. Block copolymers of polystyrene and poly(2-vinyl pyridine) have been demonstrated to form photonic crystals of 1D lamellar structure with optical band gaps that correspond to UV-to-visible light. The formation of lamellar structure toward minimum freeenergy state needs increasing polymer chain mobility, and the self-assembly process is accelerated usually by annealing, that is exposing the thin film to solvent vapor such as chloroform and dichloromethane. In this study, thin films of block copolymers were spin-coated on substrates and placed between electrode arrays of various patterns including pin-points, crossing and parallel lines. As direct or alternating currents were applied to electrode arrays during annealing process, the final structure of thin films was altered from the typical 1D lamellae in the absence of electric fields. The formation of lamellar structure was spatially controlled depending on the shape of electrode arrays, and the photonic band gap also could be modulated by electric field strength. The spatial formation of lamellar structure was examined with simulated distribution of electrical potentials by finite difference method (FDM). P2VP layers in self-assembled film were quaternized with methyl iodide vapor, and the remaining lamellar structure was investigated by field emission scanning electron microscope (FESEM). The result of this work is expected to provide ways of fabricating functional structures for display devices utilizing photonic crystal array.

Paper Details

Date Published: 14 February 2012
PDF: 6 pages
Proc. SPIE 8249, Advanced Fabrication Technologies for Micro/Nano Optics and Photonics V, 82491G (14 February 2012); doi: 10.1117/12.908423
Show Author Affiliations
Taekun Lee, Hongik Univ. (Korea, Republic of)
Jin-wook Ju, Hongik Univ. (Korea, Republic of)
Won Ryoo, Hongik Univ. (Korea, Republic of)


Published in SPIE Proceedings Vol. 8249:
Advanced Fabrication Technologies for Micro/Nano Optics and Photonics V
Winston V. Schoenfeld; Raymond C. Rumpf; Georg von Freymann, Editor(s)

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