title: Collapse of homeotropic liquid-crystal alignment by increased molecular packing on comb-like polymer surfaces.
abstract: We report an unusual alignment behavior of liquid crystals (LCs) on well-ordered comb-like poly(oxyethylene) surfaces. The homeotropic LC alignments that are observed on as-coated surfaces of the polymers are transformed to the random planar type after annealing treatment, even though the molecular structure of the polymer surface becomes more ordered and the surface energy decreases. Studies of the surface properties, such as molecular structure, morphology, and wettability, reveal that such an unexpected alteration of the LC alignment originates from the density of the alkyl side chains being enhanced by localized packing.
authors.affiliation: Department of Advanced Materials Engineering for Information & Electronics, Kyung Hee University, 446-701 Seoul, South Korea.
authors.forename: Eun-Ho
authors.initials: EH
authors.lastname: Sohn
authors.forename: Hyo
authors.initials: H
authors.lastname: Kang
authors.forename: Dong-Gyun
authors.initials: DG
authors.lastname: Kim
authors.forename: Kigook
authors.initials: K
authors.lastname: Song
authors.forename: Jong-Chan
authors.initials: JC
authors.lastname: Lee
mesh_terms: D050866:Liquid Crystals / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D011108:Polymers / Q000737:chemistry*; D013499:Surface Properties; D017155:Wettability
chemical_list: D011108:Polymers