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Volume 56, Issue 6
Displaying 1-12 of 12 articles from this issue
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Yuichiro HARAMOTO1999 Volume 56 Issue 6 Pages 335-340
Published: June 25, 1999
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSNew liquid crystal polymers having a 1, 3-dithiane ring or 1, 3-oxathiane ring were synthesized. First, the syntheses of new polymerizable liquid crystal monomers with a 1, 3-dithiane ring or 1, 3-oxathiane ring in their principal structures are discussed. Then the polymerization of these monomers and syntheses of side chain type polysiloxanes are discussed. The mesomorphic behaviors of these liquid crystal monomers and polymers are also discussed. These new liquid crystal polymers exhibit liquid crystal phase at around room temperature, and have lower nematic-sotropic transition temperatures than those of the corresponding 1, 3-dioxane type liquid crystal polymers.View full abstractDownload PDF (938K) -
Seiji UJIIE, Hiroko UCHINO, Kazuyoshi IIMURA, Moriyuki SATO1999 Volume 56 Issue 6 Pages 341-349
Published: June 25, 1999
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSLiquid crystalline binary systems (P-n-x: n=number of central methylene units of TN-n, x=mole fraction of TN-n) were built. They consisted of a side-chain polymer with ethyl terminal groups and a twin compound (TN-n) with nitro terminal groups. Liquid crystalline binary systems (T-n-x) of TN-n and a twin compound with butyl terminal groups were also built. The liquid crystallinity of P-n-x and T-n-x was examined. The relationship between the liquid crystallinity and the conformation of TN-n was discussed. The use of both the donor-acceptor interactions and the effects of the conformations led to the formation of novel assemblies. Also, the effects of the conformations were available for the control of smectic orientational structures. All the liquid crystalline binary systems produced induced smectic phases by donor-acceptor interactions between distinct mesogenic groups of the components. Even-membered P-8-x and T-8-x, in which TN-8 component has a linear-like molecular shape, showed the induced smectic A phase. Odd-membered P-7-x and T-7-x, having TN-7 component with a banana-like molecular shape, exhibited the induced smectic CA phase. The orientational structures of the induced smectic phases thus strongly depend on the conformations of the twin components.View full abstractDownload PDF (1628K) -
Masayoshi TABATA, Yoshikazu SADAHIRO, Takeyuki SONE, Yasuo INABA, Kazu ...1999 Volume 56 Issue 6 Pages 350-360
Published: June 25, 1999
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSStereospecific polymerization of acetylene esters, HC≡C-COOn-alkyl, was successfully performed using a [Rh (norbornadiene) Cl] 2 catalyst to give rise to the corresponding cis-transoid polyacetylene esters in the presence of alcohol, which is the polymerization solvent by which the dimer catalyst was dissociated. We found that the polyacetylene esters generate pseudohexagonal structures called columnar as the self-assembly in the solid state, although the columnar polymer has a helical structure as correlatively predicted by the semi-empirical quantum chemical calculation method, AM1 method. We also found that the poly (n-propiolate) polymer works as a highly oxygen permeable membrane. The separation factor α, Po2/PN2=3.4, is comparable to that for a typical oxygen permeable polymer reported before. Further we found that the ESR parameters of radicals observed in the pristine cis polymer and thermally treated polymer are quite different from each other and those radicals are created by the rotational scission of the cis C=C bonds to generate π-radicals called solitons. Therefore these facts show that the ESR methods are useful for assignment of the resultant cis and trans geometrical isomers of this polymer because of the different observed ESR parameters.View full abstractDownload PDF (3303K) -
Tadahiro ASADA, Hiroyuki TANAKA1999 Volume 56 Issue 6 Pages 361-369
Published: June 25, 1999
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSThe second harmonic generations (SHG) of liquid crystalline main-chain type polymers were investigated. The sample polymers are copolymers of 2-hydroxy-6-naphthoic acid (HNA) with 4-hydroxy-benzoic acid (PHB) in various composition ratios. The SHG of the film samples was greatly affected not only by the polymerization conditions, but also by preparation conditions of the films. SHGs for the samples processed by mechanical stretching and for electrically poled samples were compared. The nonlinear optical coefficients dexp of the electrically poled samples evaluated by Maker-Fringe method are 2-2.5 times larger than those of the mechanically oriented sample whose dexp is about 5pm V-1. The high SHG of the main-chain type NLO polymers mainly originates from the additivity of hyperpolarizability (β) of the individual unit due-to-head to tail bonding. To improve the conversion efficiency, the effect of piling mechanically oriented films was investigated. Quasi-phase matching (QPM) was also performed by piling mechanically oriented films.View full abstractDownload PDF (1692K) -
Ken KAWATA, Hideyuki NISHIKAWA, Masayuki NEGORO, Masaki OKAZAKI1999 Volume 56 Issue 6 Pages 370-377
Published: June 25, 1999
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSCoating on an orientation layer, discotic liquid crystals (triphenylene hexa-benzoate with photo-polymerizing groups) formed a uniform mono-domain discotic nematic (ND) phase and aligned to a single direction in a hybrid way. A short exposure of UV light can easily fix the novel alignment of discotic liquid crystal molecules without changing the order parameter.View full abstractDownload PDF (3758K) -
Kohsaku OKUYAMA, Toshiyuki URYU1999 Volume 56 Issue 6 Pages 378-384
Published: June 25, 1999
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSWe have synthesized main-chain type liquid-crystalline alicyclic polyethers, i. e., 2-substituted poly (4-oxycyclohexane) s, by cationic ring-opening polymerization of racemic 7-oxa-bicyclo [2.2.1] heptanes (OBH's) as monomer. Optically pure (+) -exo-2-phenyl-7-oxabicyclo [2.2.1] heptane ((+) -POBH) and (-) -POBH were separated by optical resolution on a silica gel column coated with cellulose phenylcarbamate. The optically pure monomers and monomer mixtures with various proportions were polymerized by Lewis acid catalysts in high vacuum. The NMR data suggested that stereoregular polymers were obtained from optically pure monomers. The poly ((+) -POBH) and poly ((-) -POBH) had a high specific rotation of +536°, suggesting that the polymers take a helix conformation. The stereoregularity of polymers from optically pure monomers was higher than that of polymers from mixture monomers. The optically pure polymers exhibited liquid crystallinity. These polymers showed a nematic phase in the temperature range from Tg (152-195°C) to approximately 310°C.View full abstractDownload PDF (3986K) -
Seiji UJIIE, Yumi YANO, Shinichi TANIMOTO, Moriyuki SATO1999 Volume 56 Issue 6 Pages 385-389
Published: June 25, 1999
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSNew liquid crystalline ion complexes (IC-n) were synthesized by the ion complexation of polyacrylic acid and an azobenzene derivative having an amino group. Both polyacrylic acid and the azobenzene derivative did not show a liquid crystalline phase. IC-n, having a mole fraction (n) of the azobenzene derivative form 0.2 to 0.6, exhibited a smectic A mesophase in heating and cooling processes. IC-n showed a glass transition point. In the smectic A phase, batonnets and focal conic fan textures were observed. IC-n produced a bilayer-like structure consisting of a sublayer formed by hydrophilic groups such as ionic groups and a sublayer in which the azobenzene derivatives were aligned. The ionic sublayer acts in producing and stabilizing the liquid crystalline alignment. A liquid crystalline ion complex (PAa/DA) of polyacrylic acid and dodecylamine was also prepared and compared to IC-n. PAa/DA formed a smectic A phase with a fan texture in heating and cooling processes and showed a similar liquid crystallinity to IC-n. The liquid crystalline PAa/PD does not have an aromatic mesogenic unit. These facts indicate that the liquid crystal alignment of IC-n mainly forms due to the ionic aggregation, and the azobenzene mesogenic units of IC-n do not effectively act in the liquid crystal formation.View full abstractDownload PDF (2027K) -
Keiichi MORIYA, Yasuyuki KAWANISHI, Toshiya SUZUKI, Shinichi YANO, Mei ...1999 Volume 56 Issue 6 Pages 390-395
Published: June 25, 1999
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSOrganophosphazenes with similar mesogenic moieties were prepared and their mesogenicity was studied by use of DSC measurements and polarizing microscope observations. In cyclotriphosphazenes with octyloxybiphenyl moieties, mesomorphic phase transitions of Cr-SmC-I were observed, but no mesomorphic phase was observed for the corresponding tetramer and polymer. In cyclotriphosphazenes and cyclotetraphosphazenes with Schiff base moieties, enantiotropic mesomorphisms of Cr-Sml-SmC-SmA-I and Cr-SmA-I were observed. In polyphosphazenes with similar Schiff base moietities, a mesomorphic phase was observed. A higher mesomorphic ability of the Schiff base moeties than those of alkoxybiphenyl reflects on the phase transition of organophosphazenes. The molecular structure and mesogenicity was discussed in the organophosphazenes with similar alkoxybiphenyl side groups.View full abstractDownload PDF (1154K) -
Naoko MIKAMI, Masao HONMA1999 Volume 56 Issue 6 Pages 396-400
Published: June 25, 1999
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSPoly (DL-amino acid) s (poly-DL-Leu, Ala, Gly, and Phe) and fibrous proteins (fibroin, keratin, and sericin) are studied as alignment films for ferroelectric liquid crystal (FLC) devices. On the alignment film obtained from fibroin, the average director of FLC molecules was oriented normal to the rubbing direction of the film. The optically inactive poly (DL-alanine) film showed the same orientation of FLCs.View full abstractDownload PDF (897K) -
Hiroyuki NOHIRA, Michihiro YAMADA, Daiyou TERUNUMA, Misako NOHIRA1999 Volume 56 Issue 6 Pages 401-405
Published: June 25, 1999
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSThree kinds of liquid crystal monomers which have a trifluoromethyl asymmetric frame and a terminal vinyl group were synthesized. They were then dimerized by hydrosilylation reaction to give dimeric liquid crystals and polymerized to give side-chain liquid crystal polymers. By measuring the physical properties of these liquid crystals, we found that dimers and polymers synthesized from ferroelectric monomers showed broad temperature ranges of ferroelectric phases, spontaneous polarizations of between 1000-2500μCm-2, and response times of between 115-2800μs. They also showed large tilt angles. The dimer and polymer derived from an antiferroelectric liquid crystal monomer did not show any antiferroelectric phases, but did show a highly-ordered smectic X* phase.View full abstractDownload PDF (759K) -
Effects of Addition of Calamitic Liquid Crystal Molecule on the Poly (di-n-hexylsilane) ConformationShusaku NAGANO, Takahiro SEKI, Kunihiro ICHIMURA1999 Volume 56 Issue 6 Pages 406-409
Published: June 25, 1999
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSMixed films consisting of poly (di-n-hexylsilane) (PDHS) and three kinds of calamitic liquid crystals (LCs) were prepared. The conformational state of PDHS was evaluated by UV spectroscopy. In these mixed films, the absorption band corresponding to the crystalline phase showed a red shift from that of the pure PDHS film. This shift was obvious at a low molar mixing ratio [LC] / [PDHS] of 0.05. Thus, calamitic liquid crystal molecules promoted the extention of the all-trans-zigzag conformation of PDHS.View full abstractDownload PDF (720K) -
Takashi KATO, Masumi OGASAWARA, Seiji UJIIE1999 Volume 56 Issue 6 Pages 410-413
Published: June 25, 1999
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSThe formation of double hydrogen bonds between a 2, 6-bis (acylamino) pyridine group and a benzoic acid moiety in the side-chain of polyacrylates or a polymethacrylate leads to the induction of a mesophase. Monotropic mesophases are observed for these complexes below about 120°C. The growth of dendritic textures at the isotropic-mesomorphic transition is seen for a polymeric complex under polarizing microscope observation, which suggests that these complexes show a hexagonal mesomorphic phase.View full abstractDownload PDF (1967K)
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