title: Macroscopic alignment of chromonic liquid crystals using patterned substrates.
abstract: We demonstrate an efficient technique to align lyotropic chromonic liquid crystals (LCLCs) using secondary sputtering lithography (SSL). Monodomains of LCLCs prepared using SSL maintained their stable alignment for days. A generalization of Berreman's theory was employed to determine the anchoring strength of LCLCs on tessellated surface patterns. The anchoring energy initially increases with the amplitude (A) of the grooves and excellent alignment of LCLCs was observed when the amplitude of the grooves is equal to half its wavelength (λ). We also note that the anchoring energy levels off above qA∼ 3 (where q = 2π/λ), which suggests that increasing qA beyond a certain value does not provide any further advantage for the alignment of LCLCs. This finding provides a useful optimization criterion for the fabrication of the patterned cells to achieve stable monodomain alignment of LCLCs. Our analysis also explains why good alignment of LCLCs has been a difficult task.
authors.affiliation: National Research Laboratory for Organic Opto-Electronic Materials, Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Korea. heetae@kaist.ac.kr.
authors.forename: Jeong Yeon
authors.initials: JY
authors.lastname: Kim
authors.forename: Karthik
authors.initials: K
authors.lastname: Nayani
authors.forename: Hyeon Su
authors.initials: HS
authors.lastname: Jeong
authors.forename: Hwan-Jin
authors.initials: HJ
authors.lastname: Jeon
authors.forename: Hae-Wook
authors.initials: HW
authors.lastname: Yoo
authors.forename: Eun Hyung
authors.initials: EH
authors.lastname: Lee
authors.forename: Jung Ok
authors.initials: JO
authors.lastname: Park
authors.forename: Mohan
authors.initials: M
authors.lastname: Srinivasarao
authors.forename: Hee-Tae
authors.initials: HT
authors.lastname: Jung