Novel Reverse-Mode Light Switching of (Pseudo Side-Chain Liquid Crystalline Copolymer Resulting in Spontaneous Homeotropic Alignment/Liquid Crystals) Composite System

1999 ◽  
Vol 30 (1) ◽  
pp. 660 ◽  
Author(s):  
H. Yamane ◽  
H. Kikuchi ◽  
T. Kajiyama
Keyword(s):  
Liquid Crystals ◽  
Liquid Crystalline ◽  
Composite System ◽  
Side Chain ◽  
Reverse Mode ◽  
Homeotropic Alignment

Spontaneous homeotropic alignment of nematic liquid crystals induced by a double-armed side chain liquid crystalline polymethacrylate

2017 ◽  
Vol 656 (1) ◽  
pp. 96-104 ◽  
Author(s):  
Osamu Haba ◽  
Wataru Matsuno ◽  
Nao Nakamura ◽  
Hiroshi Awano ◽  
Tatsuhiro Takahashi ◽  
...  
Keyword(s):  
Liquid Crystals ◽  
Liquid Crystalline ◽  
Nematic Liquid Crystals ◽  
Side Chain ◽  
Homeotropic Alignment

Liquid Crystal Elastomers with Piezoelectric Properties

MRS Bulletin ◽  
1991 ◽  
Vol 16 (1) ◽  
pp. 29-31 ◽  
Author(s):  
Wolfgang Meier ◽  
Heino Finkelmann
Keyword(s):  
Liquid Crystals ◽  
Liquid Crystalline ◽  
Three Dimensional ◽  
Polymer Chains ◽  
Side Chain ◽  
Shape Stability ◽  
Technical Application ◽  
Mechanical Field ◽  
Dimensional Network ◽  
Liquid Crystal Elastomers

During the last few years, liquid crystalline elastomers (LCEs) have been systematically produced by cross-linking liquid crystalline side-chain polymers. In these networks, a liquid crystalline molecule is fixed at each monomeric unit. LCEs exhibit a novel combination of properties. Due to liquid crystalline groups, they show anisotropic liquid crystalline properties similar to conventional liquid crystals (LCs); but due to the three-dimensional network-structure of the polymer chains, they show typical elastomer properties, such as rubber elasticity or shape stability. One exceptional property of this combination is demonstrated when a mechanical deformation to the LCE causes macroscopically uniform orientation of the long molecular axis of the LC units (the so-called “director”).This response of the LC-phase structure to an applied mechanical field is similar to the effect of electric or magnetic fields on low molecular weight liquid crystals (LMLC), as illustrated in Figure 1. Figure la shows an undeformed LCE. Because of the non-uniform orientation of the director, the sample scatters light strongly so the elastomer is translucent like frosted glass. On the other hand, applying a mechanical field the director becomes uniformly aligned and the sample is transparent (Figure 1b). Such a macroscopically ordered rubber exhibits optical properties very similar to single crystals. These propertie s of LCEs offer new prospects for technical application, e.g., in nonlinear and integrated optics.

Flory's parameters in solutions of liquid-crystalline side-chain polymers in low-molecular weight liquid crystals

1990 ◽  
Vol 23 (23) ◽  
pp. 5020-5024 ◽  
Author(s):  
Gilles Sigaud ◽  
M. F. Achard ◽  
F. Hardouin ◽  
C. Coulon ◽  
H. Richard ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Liquid Crystals ◽  
Liquid Crystalline ◽  
Side Chain ◽  
Low Molecular Weight

scholarly journals Discotic liquid crystals of transition metal complexes 50: spiranthes-like supramolecular structure of phthalocyanine-fullerene dyads

2014 ◽  
Vol 18 (05) ◽  
pp. 366-379 ◽  
Author(s):  
Aya Ishikawa ◽  
Kenta Ono ◽  
Kazuchika Ohta ◽  
Mikio Yasutake ◽  
Musubu Ichikawa ◽  
...  
Keyword(s):  
Liquid Crystals ◽  
Transition Metal Complexes ◽  
Supramolecular Structure ◽  
Liquid Crystalline ◽  
Molecular Design ◽  
Glass Plate ◽  
Helical Structure ◽  
Discotic Liquid Crystals ◽  
One Dimensional ◽  
Homeotropic Alignment

We have synthesized novel liquid crystalline Pc - C 60 dyads (CnS)6PcCu-C60 (n = 14, 16, 18: 1a–1c) by using our developed synthetic method in order to investigate the mesomorphism and alignment behavior. Each of the (CnS)6PcCu-C60 dyads shows perfect homeotropic alignment in the Colho mesophase between two glass plates for n = 14, 16, 18 and also on a glass plate for n = 14, although none of the parent Pc compounds (CnS)8PcCu and the Pc precursors (CnS)6PcCu-OH and (CnS)6PcCu-OFBA shows homeotropic alignment. It may be attributed to the strong affinity between fullerene and glass surface. Although the reason is not so clear at the present time, this is very useful guideline for the molecular design to prepare homeotropic alignment-showing discotic liquid crystals. Very interestingly, the spherical C 60 parts form a helical structure around the column formed by the disk-like Pc parts This supramolecular structure very resembles spiranthes. The spiranthes-like supramolecular structure is compatible with one-dimensional nano-array expecting the high conversion efficiency of solar cells.

Rheology of Liquid-Crystalline Polymers

2007 ◽  
Author(s):  
Chang Dae Han
Keyword(s):  
Liquid Crystals ◽  
Polymer Chain ◽  
Liquid State ◽  
Liquid Crystalline ◽  
Main Chain ◽  
Liquid Crystalline Polymers ◽  
Point Of View ◽  
Side Chain ◽  
Crystalline Polymers ◽  
Molecular Features

Liquid crystals (LCs) may be divided into two subgroups: (1) lyotropic LCs, formed by mixing rigid rodlike molecules with a solvent, and (2) thermotropic LCs, formed by heating. One finds in the literature such terms as mesomorphs, mesoforms, mesomorphic states, and anisotropic liquids. The molecules in LCs have an orderly arrangement, and different orders of structures (nematic, smectic, or cholesteric structure) have been observed, as schematically shown in Figure 9.1. The kinds of molecules that form LCs generally possess certain common molecular features. The structural characteristics that determine the type of mesomorphism exhibited by various molecules have been reviewed. At present, our understanding of polymeric liquid crystals, often referred to as liquid-crystalline polymers (LCPs), is largely derived from studies of monomeric liquid crystals. However, LCPs may exhibit intrinsic differences from their monomeric counterparts because of the concatenation of monomers to form the chainlike macromolecules. The linkage of monomers inevitably means a loss of their translational and orientational independence, which in turn profoundly affects the dynamics of polymers in the liquid state. These intramolecular structural constraints are expressed in the flexibility of the polymer chain. Generally speaking, the chemical constitution of the monomer determines the flexibility and equilibrium dimensions of the polymer chain (Gray 1962). Figure 9.2 illustrates the variability of chain conformation (flexible chain, semiflexible chain, and rigid rodlike chain) forming macromolecules. Across this spectrum of chain flexibility, the persistence in the orientation of successive monomer units varies from the extreme of random orientation (flexible chains) to perfect order (the rigid rod). Hence, efforts have been made to synthesize LCPs that consist of rigid segments contributing to the formation of a mesophase and flexible segments contributing to the mobility of the entire macromolecule in the liquid state (Ober et al. 1984). From the point of view of molecular architecture, as schematically shown in Figure 9.3, two types of LCP have been developed: (1) main-chain LCPs (MCLCPs), having the monomeric liquid crystals (i.e., mesogenic group) in the main chain of flexible links, and (2) side-chain LCPs (SCLCPs), having the monomeric liquid crystals attached, as a pendent side chain, to the main chain.

Sign in / Sign up

Export Citation Format

Share Document