5693-28-7Relevant academic research and scientific papers
Synthesis and thermal properties of cholesteryl 4-n-alkoxy-3-methoxybenzoates
Kasuga, Kazuyuki,Hatakeyama, Hyoe,Hatakeyama, Tatsuko
, p. 1 - 14 (2007/10/02)
A homologous series of new liquid crystalline compounds, cholesteryl 4-n-alkoxy-3-methoxybenzoate were synthesized from vanillin and their mesomorphic properties were studied by differential scanning calorimetry, polarizing microscopy and x-ray diffractometry.Each of the homologues from cholesteryl 3,4-dimethoxybenzoate (n=1) to cholesteryl 4-n-hexyloxy-3-methoxybenzoate (n=6) showed a cholesteric-nematic phase (NCh).The other higher homologues (from n=7 to n=18) indicated smectic A (SA) and NCh phases.The temperature region of smectic phases increased with the increase of the chain length of the n-alkoxy group.Transition temperatures in each of the homologues were lower than those in a corresponding non-3-methoxy substituted benzoate ester, due to the destabilizing effect of the lateral methoxy group.The effect was more significant on the homologues having a shorter n-alkoxy chain.It was also found that these esters formed a glassy state by quenching from mesophases and/or the isotropic liquid phase.The change of the glass transition temperature on each homologue (from n=1 to n=6) suggested the effect of the chain length of the n-alkoxyl group on the formation of the glassy state.Keywords: liquid crystals, thermal properties, differential scanning calorimetry, cholesteric phas, smectic A phase, glassy phase.
