The Influence of Hydrogen Bonding on the Mesomorphic Properties of Side Chain Type Liquid Crystalline Polyurethanes with Rigid Moieties in the Polymer Backbone

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.

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Hydrogen Bonding and Mesomorphic Properties for Side Chain Type Liquid Crystalline Polyurethanes Containing Rigid Moieties in the Polymer Backbone

Polymer Journal ◽

10.1295/polymj.29.134 ◽

1997 ◽

Vol 29 (2) ◽

pp. 134-137 ◽

Cited By ~ 3

Author(s):

Takashi Mihara ◽

Naoyuki Koide

Keyword(s):

Hydrogen Bonding ◽

Liquid Crystalline ◽

Side Chain ◽

Polymer Backbone ◽

Mesomorphic Properties ◽

Chain Type

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Mesomorphic Properties of Side Chain Type Liquid Crystalline Copolyesters with Polar and Non-Polar Groups in the End of the Mesogen

Polymer Journal ◽

10.1295/polymj.29.142 ◽

1997 ◽

Vol 29 (2) ◽

pp. 142-146

Author(s):

Kohji Ogawa ◽

Takashi Mihara ◽

Naoyuki Koide

Keyword(s):

Liquid Crystalline ◽

Side Chain ◽

Polar Groups ◽

Mesomorphic Properties ◽

Chain Type

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

MRS Proceedings ◽

10.1557/proc-425-79 ◽

1996 ◽

Vol 425 ◽

Cited By ~ 1

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.

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