Structural study of thermotropic liquid crystalline poly(ethyleneiminium) salts alkylated with mesogenic side chains

Authors

  • Patrick Masson,

    Corresponding author
    1. Institut de Physique et Chimie des Matériaux de Strasbourg, (UMR 46) CNRS-ULP-EHICS, Groupe des Matériaux Organiques, 23 rue du Loess BP 20 CR, 67037 Strasbourg Cédex, France
    • Institut de Physique et Chimie des Matériaux de Strasbourg, (UMR 46) CNRS-ULP-EHICS, Groupe des Matériaux Organiques, 23 rue du Loess BP 20 CR, 67037 Strasbourg Cédex, France
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  • Philippe Gramain,

    1. Institut Charles Sadron, (UPR 22) CNRS-ULP, 6 rue Boussingault, 67083 Strasbourg Cédex, France
    Current affiliation:
    1. Ecole Nationale Supériéure de Chimie de Montpellier, Laboratoire de Chimie Appliquée, URA-CNRS-1193, 8 rue de l'Ecole Normale, 34053 Montpellier Cédex 1, France
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  • Daniel Guillon

    1. Institut de Physique et Chimie des Matériaux de Strasbourg, (UMR 46) CNRS-ULP-EHICS, Groupe des Matériaux Organiques, 23 rue du Loess BP 20 CR, 67037 Strasbourg Cédex, France
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Abstract

Ionic liquid crystalline polymers were obtained from linear poly(ethyleneimine) (PEI) substituted with 6-(4-methoxy-4′-biphenyloxy)hexyl bromide or 12-(4-methoxy-4′-biphenylyloxy)dodecyl bromide, and quaternised with dimethyl sulfate or hydrobromic acid. Their thermotropic polymorphism was studied by means of differential scanning calorimetry (DSC), polarising optical microscopy and X-ray diffraction. A smectic A mesophase was identified and described from a structural point of view with the help of computer modelling. The completely alkylated and quaternised PEI derivative was shown to form a single layered smectic A structure with pendant groups all on the same side of the polymer backbone in a double row ribbon-like configuration. The ribbon-like polymer chains are packed side by side with the polymer backbone parallel to the smectic layers and the mesogenic groups perpendicular to them. For partially alkylated or quaternised PEI derivatives, the layer spacing in the smectic A mesophase is generally different from that of the corresponding molecular length calculated for fully functionalised polymers.

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