Liquid-crystalline behaviour of 4-(ω-aminoalkyloxy)-4′-cyanobiphenyls and their side chain epoxy polymers

Chien, Liang–Chy; Cada, Leonorina G.; Xie, Linghai

doi:10.1080/02678299208029128

Cited by 12 publications

(5 citation statements)

References 3 publications

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“…The mesogenic compound used is novel in that it possesses not only the usual flexible (alkyl chain) and rigid (biphenyl) moieties characteristic of low molar mass liquid crystals but also a polar head group located at the opposite end of one of the alkyl chains from the mesogen. These types of compounds are only recently receiving increased attention. ,,− …”

Section: Resultsmentioning

confidence: 99%

Mixtures of an Acid-Functionalized Mesogen with Poly(4-vinylpyridine)

and

Bazuin

1996

Chem. Mater.

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A thermotropic dialkoxy biphenyl liquid crystal, functionalized by a carboxylic acid group at one extremity, is mixed to varying proportions with poly(4-vinylpyridine) (P4VP). The liquid crystal, LC-4,6A, is characterized by a monotropic smectic A phase and a highly ordered or crystalline lamellar phase formed primarily of acid dimers. In the mixtures with P4VP (studied up to acid/pyridine molar ratios of 1.0), the fluid mesophase is suppressed. A solidisotropic phase transition is present above a molar ratio of about 0.2, whereas for lower LC-4,6A contents the mixtures form an apparently miscible, amorphous material. The glass transition temperature, T g , of the latter is strongly depressed, at a rate of 7 °C/mol % LC-4,6A up to a molar ratio of 0.1, after which the T g remains essentially constant. As supported by infrared analysis, the plasticization behavior is attributed to strong hydrogen bonding between the acid and pyridine moieties, which solubilizes the LC-4,6A molecules within the polymer matrix. When the solubility limit is reached, the excess small molecule solidifies into an ordered phase that is essentially identical to that of neat LC-4,6A. This phase can be modified by quenching from the melt, which freezes in a greater proportion of the acidpyridine interactions and leads to incorporation into this phase of significant amounts of P4VP.

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Section: Resultsmentioning

confidence: 99%

Mixtures of an Acid-Functionalized Mesogen with Poly(4-vinylpyridine)

and

Bazuin

1996

Chem. Mater.

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“…Ethylene glycol diglycidyl ether (EGDE) was obtained from Aldrich Chemical Co. and used as received. Mesogenic amines C6, C7, C8, and C9 were synthesized in our laboratory; the detailed synthesis scheme has been reported elsewhere .…”

Section: Methodsmentioning

confidence: 99%

“…Mesogenic amines C6, C7, C8, and C9 were synthesized in our laboratory; the detailed synthesis scheme has been reported elsewhere. 3 The side-chain liquid crystalline epoxies EGDE-C6, EGDE-C7, EGDE-C8, and EGDE-C9 were synthesized by a ring-operating reaction of EGDE with mesogenic amines, are shown in Figure 1. Equivalent amounts of the EGDE and amine were charged into a polymerization vessel purged with circulating dry nitrogen.…”

Section: Methodsmentioning

confidence: 99%

“…1 In order to gain insight into the structure of dispersed LC domains and to critically match the refractive index of the side-chain liquid crystalline polymers with that of the low molar mass LC, we have synthesized a series of epoxy resins [ethylene glycol diglycidyl ether (EGDE) grafted with mesogenic amines 4-(ω-aminoalkoxy)-4′cyanobiphenyl connected by various methylene linkages (EGDE-Cx, where x is the number of methylene carbons). 3 The dispersing low molar mass LC is the eutectic liquid crystal mixture consisting of cyanobi-phenyl derivatives, commercially known as E7. We first examined the phase behavior for the mixtures of these epoxy polymers and E7 by establishing various phase diagrams of EGDE-Cx/E7 mixtures where x ) 6-9.…”

Section: Introductionmentioning

confidence: 99%

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Phase Diagrams and Phase Separation Dynamics in Mixtures of Side-Chain Liquid Crystalline Polymers and Low Molar Mass Liquid Crystals

Chiu¹,

Zhou²,

Kyu³

et al. 1996

Macromolecules

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Miscibility phase diagrams and phase separation dynamics in mixtures of side-chain liquid crystalline polymers (SCLCP) and monomeric liquid crystals have been investigated experimentally in order to test with theoretical predictions. The theoretical calculation on equilibrium phase diagrams of binary nematic mixtures involves a combination of the Flory-Huggins (FH) free energy for isotropic mixing in conjunction with the Maier-Saupe (MS) free energy for nematic ordering of the mesogenic units. Two orientational order parameters and two nematic-isotropic (NI) transitions of the constituent mesogens are taken into consideration in the calculation. This combined FH-MS theory predicts a variety of phase diagrams depending on the relative strength of the cross-interaction between two dissimilar mesogens as compared to that in the same species. A series of epoxy resins [ethylene glycol glycidyl ether (EGDE)] grafted with mesogenic amines 4-(ω-aminoalkoxy)-4′-cyanobiphenyl were synthesized. The temperature-composition phase diagrams of these SCLCP mixtures and the eutectic low molar mass liquid crystal (E7) have been established by a cloud point method. The calculated phase diagrams are found to accord well with the experimental phase diagrams. The dynamics of phase separation has been investigated by means of time-resolved light scattering and optical microscopy. The time evolution of the structure factor following various temperature quenches into the nematic-liquid and/or nematicnematic coexistence regions has been analyzed in terms of a power law scheme.

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“…S3a in the ESI †). 13 Upon hybridization with ZnO NPs (decreasing the ratio of LC to ZnO/OA from 7.4 to 0.7 molar eq), T m shifts to 44 C and T c increases to 133 C (see Fig. S3b and S4 in the ESI †).…”

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confidence: 99%