Faculté des sciences

Fullerene-containing liquid-crystalline dendrimers

Dardel, Blaise ; Guillon, Daniel ; Heinrich, Benoît ; Deschenaux, Robert

In: Journal of Materials Chemistry, 2001, vol. 11, p. 2814 - 2831

Addition reaction of mesomorphic malonate-based dendrimers (up to the fourth generation) with C60 gave liquid-crystalline fullerene derivatives. The cyanobiphenyl unit was used as liquid-crystalline promoter. The malonates presented nematic and/or smectic A phases. The fullerenes showed only smectic A phases, with the exception of the second generation dendrimer for which smectic A and... More

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    Summary
    Addition reaction of mesomorphic malonate-based dendrimers (up to the fourth generation) with C60 gave liquid-crystalline fullerene derivatives. The cyanobiphenyl unit was used as liquid-crystalline promoter. The malonates presented nematic and/or smectic A phases. The fullerenes showed only smectic A phases, with the exception of the second generation dendrimer for which smectic A and nematic phases were observed. The supramolecular organization of the fullerene-based molecular units within the smectic A layers was investigated by X-ray diffraction. Two structural regimes were determined. For the low generation dendrimers, the supramolecular organization is determined by steric factors. For the high generation dendrimers, the mesogenic groups impose a microphase organization: due to lateral extension of the branching part of the molecule, the cyanobiphenyl groups arrange in a parallel fashion as in classical smectic A phases, the rest of the macromolecule being located between the mesogenic sublayers.