NMR investigation of a thermotropic liquid crystal showing isotropic-isotropic'-(columnar)-cubic phase transitions

• In this work, we report a first detailed study of the mesophasic behaviour of the calamitic liquid crystal, a (4,4′-bis(4″-carboxybelzyloxy)biphenyl derivate, labelled 9/2 RS/RS, showing an isotropic-isotropic-(columnar)-cubic phase behaviour on cooling. 1H NMR diffusometry allowed to distinguish between the two isotropic phases in terms of diffusion characterized by different Arrhenius activation energy, while 13C NMR static measurements and 2H NMR investigations were of help in understanding the orientational ordering properties of the metastable columnar phase and confirmed the isotropic state of the sample in the cubic phase.

Ämnesord

NATURVETENSKAP  -- Kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences (hsv//eng)

Nyckelord

Liquid crystals

Metastable phases

Thermotropic liquid crystals

Arrhenius activation energy

Calamitic liquid crystal

Columnar phase

Isotropic phasis

Isotropic state

NMR diffusometry

Orientational orderings

Static measurements

Activation energy

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