The Effect of Hydrogen Bonding on the Mesomorphic Properties for Side Chain Type Liquid Crystalline Polyurethanes

1996 ◽  
Vol 425 ◽  
Author(s):  
T. Mihara ◽  
N. Koide
Keyword(s):  
Hydrogen Bonding ◽  
Liquid Crystalline ◽  
Side Chain ◽  
Flexible Chain ◽  
Remarkable Change ◽  
Polymer Backbone ◽  
Phase Transition Temperatures ◽  
Ft Ir ◽  
Mesomorphic Properties ◽  
Chain Type

AbstractMesomorphic properties and temperature dependence of the hydrogen bonding between urethane bonds (H-bonding) for side chain type liquid crystalline polyurethane(SLCPU)s were studied by thermally controlled FT-IR spectroscopy. A remarkable change in the strength of H-bonding for SLCPUs with a flexible chain in the polymer backbone(flexible SLCPUs) was displayed near the phase transition temperatures, while small changes in the strength of H-bonding for SLCPUs with a rigid moiety in the polymer backbone(rigid SLCPUs) was influenced by a mesogenic group in the side chain and the flexible chain length in the polymer backbone. Furthermore, in order to study the influence of H-bonding in rigid SLCPUs, polyurethane derivatives with methyl group were synthesized replacing hydrogen in urethane bonds. No mesomorphic properties for polyurethane derivatives obtained were exhibited. It was concluded that H-bonding played an important role to exhibit mesomorphic properties of rigid SLCPUs.

Synthesis and Physical Properties of π -Conjugated Polymers Containing Mesogenic Group

1996 ◽  
Vol 425 ◽  
Author(s):  
Y. Watanabe ◽  
N. Koide
Keyword(s):  
Aromatic Compound ◽  
Liquid Crystalline ◽  
Oxidation Potential ◽  
Side Chain ◽  
Mesogenic Group ◽  
Scanning Calorimetry ◽  
Polymer Backbone ◽  
Crystalline Polymers ◽  
Lower Oxidation ◽  
Chain Type

AbstractNovel side chain type liquid crystalline polymers, polythiophene and poly(aryleneethynylene) [PAE], containing a mesogenic group in the side chain were synthesized. Polythiophene derivatives were obtained by dehalogenative polycondensation with zero-valence nickel complex under mild condition. PAE type polymers were obtained by coupling dihalo aromatic compound with diethynyl aromatic compound. Their thermal properties were examined by differential scanning calorimetry, optical microscopy and X-ray diffractometry. All polymers exhibited a smectic or nematic mesophase depending upon the polymer backbone and pendant mesogenic group. Polythiophene derivatives exhibited electrochemical activity. Annealing polythiophene derivatives led to a lower oxidation potential and a higher conductivity. The degree of the orientation of the polymer backbone was supported by polarized UV-vis measurement. An effective conjugated length became longer by introducing thiophene rings into the polymer backbone. A high quantum yield of fluorescence was observed for PAE type polymers.

Double Ordered Layers within Microphase-separated Lamellar Structure of Double Liquid Crystalline Side-chain Type Block Copolymer

2008 ◽  
Vol 37 (11) ◽  
pp. 1174-1175 ◽  
Author(s):  
Rina Maeda ◽  
Teruaki Hayakawa ◽  
Masatoshi Tokita ◽  
Masa-aki Kakimoto ◽  
Hiroaki Urushibata
Keyword(s):  
Block Copolymer ◽  
Lamellar Structure ◽  
Liquid Crystalline ◽  
Side Chain ◽  
Chain Type ◽  
Ordered Layers

Liquid Crystalline Properties of 4,4and#39;-methylenebis(N-(4-Alkanoxybenzylidene)aniline): Synthesis, Characterization, and Theoretical study

2019 ◽  
Vol 41 (6) ◽  
pp. 1107-1107
Author(s):  
Mohammed Taha Yaseen and Abdullah Hussein Kshash Mohammed Taha Yaseen and Abdullah Hussein Kshash
Keyword(s):  
Liquid Crystalline ◽  
Theoretical Study ◽  
Basis Set ◽  
Spectroscopic Techniques ◽  
Benzene Nucleus ◽  
Crystal Properties ◽  
Ft Ir ◽  
Alkoxy Groups ◽  
Gaussian Program ◽  
Mesomorphic Properties

The paper presents six homologues series of Schiff bases ether compounds distinguished by the length of terminal alkoxy groups which substituted on a side benzene nucleus. The above structures were demonstrated through the use of spectroscopic techniques, like FT- IR and 1H-NMR. Polarized hot stage optical microscopy was used to study both mesomorphic properties and phase transitions. The results showed that out of the six compounds only three (B2, B3 and B4) were pure (marble) nematic mesophase, while no liquid crystal properties for (B5, B6 and B7) compounds. The theoretical study for the electronic structures was intended to study the effects of alkyl chain length on the electronic structure by using Gaussian program, DFT and 6-31G as basis set. The theoretical results indicate that there is no effect to the terminal substituted alkoxy groups on the HOMO energies but there is an effect on LUMO energies through decreasing energy for the prepared compounds.

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