Synthese und ferroelektrische Eigenschaften chiraler Ester von 2,5-Diphenylpyrimidinen mit α-Fluorcarbonsäuren / Synthesis and Ferroelectric Properties of 2,5-Diphenylpyrimidines with Different α-Fluorocarboxylic Acids

Abstract

Chiral esters of 2-[4-n-hexylphenyl]-5-[4-hydroxyphenyl]pyrimidine and 2-[4-n-hexyloxyphenyl]-5-[4-hydroxyphenyl]pyrimidine with four different α-fluorocarboxylic acids have been synthesized. The spontaneous polarization and the tilt angles in the smectic C* phase were measured as a function of temperature. All compounds exhibit wide range smectic C* phases, the highest values of the spontaneous polarization being about 400 nC/cm2. Additionally the spontaneous polarization in a higher ordered smectic phase was determined, the values ranging up to about 600 nC/cm2. The spontaneous polarization/tilt angle ratio strongly increases with decreasing temperature.