화학공학소재연구정보센터
Molecular Crystals and Liquid Crystals Science and Technology. Section A. Molecular Crystals and Liquid Crystals, Vol.287, 69-82, 1996
Thermal Study of an Antiferroelectric Liquid-Crystal
A full thermal study of the antiferroelectric liquid crystal (R)-1-methylheptyl 4’-(4"-decyloxybenzoyloxy)biphenyl-4-carboxylate (MHDOBBC) has been carried out by high resolution ac calorimetry, DSC and the analysis of the implemented and denoted "thermistor method". The melting and the freezing transitions of Sc-A* have been studied using the latter method, with regard to pre-transitional effects, conversion rates, metastability and latent heat ratio. A new monotropic phase has been detected following investigations by ac calorimetry, X-rays, dielectric measurements and optical observation and its possible identity is discussed. The S-A-S-C* transition is well described by the extended Landau model and a comparative analysis is performed with the related compounds MHPOBC and MHPOCBC. No clear evidence of phase restructuring appears in ac calorimetry and DSC measurements, except for an anomaly close to the Sc*gamma-Sc-A* transition.