Abstract
A series of cyclic siloxane tetramers covering the whole composition range were synthesised using cyclotetrasiloxane, cholestryl-4-allyloxy-benzoate and biphenyl-4-yl 4-allyloxybenzoate, and the effects of the cholesteryl-based mesogenic units on liquid crystalline and thermo-optical properties were studied. The presence of a cholesteric mesogen was observed to widen the mesogenic temperature range and tended to induce smectic A phases in the tetramers containing a higher mole fraction of cholestryl-4-allyloxy-benzoate (X chol). The selective reflection of cholesteric tetramers shifted to shorter wavelengths with increasing X chol and temperature. Blue phases can be easily observed for those tetramers containing more than 50.0 mol% cholesteric mesogen. The shorter pitch sample showed the wider blue phases range. The blue phases range width increased from 2.8°C to 18.5°C as X chol increased from 0.5 to 1.0.
Published Version
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