Alignment of unconventional nematic liquid crystals

被引:8
|
作者
Kumar, T. Arun [1 ]
Le, K. V. [2 ]
Kim, Jin Ki [2 ]
Takezoe, H. [2 ]
Dhara, Surajit [1 ]
机构
[1] Univ Hyderabad, Sch Phys, Hyderabad 500134, Andhra Pradesh, India
[2] Tokyo Inst Technol, Dept Organ & Polymer Mat, Tokyo, Japan
关键词
bent-core liquid crystals; planar alignment; homeotropic alignment; dielectric anisotropy; BENT-CORE; TRANSITIONS; PHASE;
D O I
10.1080/02678292.2011.585522
中图分类号
O6 [化学];
学科分类号
0703 ;
摘要
Planar (homogeneous) and homeotropic alignment of some unconventional nematic liquid crystals with both positive (Delta epsilon 0) and negative (Delta epsilon<0) dielectric anisotropies are studied on planar (AL-1254) and homeotropic (JALS-204, SE-1211) alignment layers. Irrespective of the sign of dielectric anisotropy and molecular structure, uniform planar alignment of the director is observed in Al-1254 coated cells whereas no stable homeotropic alignment of bent-core compounds with Delta epsilon<0 is observed in cells coated with JALS-204 or SE-1211. Alignment properties of these two types (Delta epsilon>0 and Delta epsilon<0) of unconventional nematic liquid crystals are explained considering the steric, short-range dipolar and long-range van der Waals interactions at the interface. A bent-core compound (Delta epsilon<0) which has no higher-order liquid crystalline phase except for the nematic exhibits a narrow temperature range of homeotropic state (on JALS-204) while cooling from the isotropic phase followed by an anchoring transition to a planar state as the temperature is further lowered. The measured polar anchoring energy of this compound on JALS-204 is significantly lower than many known calamitic liquid crystals and is responsible to the anchoring transition observed.
引用
收藏
页码:917 / 924
页数:8
相关论文
共 50 条
  • [1] ALIGNMENT OF NEMATIC LIQUID CRYSTALS
    LEE, JD
    ERINGEN, AC
    [J]. JOURNAL OF CHEMICAL PHYSICS, 1971, 55 (09): : 4504 - &
  • [2] MAGNETIC ALIGNMENT OF NEMATIC LIQUID CRYSTALS
    KESSLER, JO
    [J]. ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, 1969, (SEP): : CO88 - &
  • [3] Symmetries and alignment of biaxial nematic liquid crystals
    Karahaliou, Panagiota K.
    Vanakaras, Alexandros G.
    Photinos, Demetri J.
    [J]. JOURNAL OF CHEMICAL PHYSICS, 2009, 131 (12):
  • [4] Surface alignment of ferroelectric nematic liquid crystals
    Caimi, Federico
    Nava, Giovanni
    Barboza, Raouf
    Clark, Noel A.
    Korblova, Eva
    Walba, David M.
    Bellini, Tommaso
    Lucchetti, Liana
    [J]. SOFT MATTER, 2021, 17 (35) : 8130 - 8139
  • [5] ALIGNMENT OF NEMATIC LIQUID-CRYSTALS - COMMENT
    SHAHINPOOR, M
    [J]. JOURNAL OF CHEMICAL PHYSICS, 1975, 63 (03): : 1319 - 1320
  • [6] Alignment of carbon nanotubes in nematic liquid crystals
    van der Schoot, Paul
    Popa-Nita, V.
    Kralj, S.
    [J]. JOURNAL OF PHYSICAL CHEMISTRY B, 2008, 112 (15): : 4512 - 4518
  • [7] Photocontrolled alignment of chiral nematic liquid crystals
    Ruslim, C
    Ichimura, K
    [J]. ADVANCED MATERIALS, 2001, 13 (09) : 641 - 644
  • [8] ALIGNMENT OF NEMATIC LIQUID-CRYSTALS AND THEIR MIXTURES
    COGNARD, J
    [J]. MOLECULAR CRYSTALS AND LIQUID CRYSTALS, 1982, : 1 - 77
  • [9] ALIGNMENT OF NEMATIC AND SMECTIC LIQUID-CRYSTALS
    HAUCK, G
    KOSWIG, HD
    [J]. MOLECULAR CRYSTALS AND LIQUID CRYSTALS, 1990, 179 : 435 - 444
  • [10] MOLECULAR ALIGNMENT IN NEMATIC LIQUID-CRYSTALS
    RAO, NVS
    [J]. MOLECULAR CRYSTALS AND LIQUID CRYSTALS, 1984, 108 (3-4) : 231 - 243