DIFFERENTIAL THERMAL-ANALYSIS (DTA) UNDER HIGH-PRESSURE .6. PHASE-TRANSITIONS OF SOME LIQUID-CRYSTALS UP TO 3-KBAR

被引：26

作者：

SPRATTE, W ^{[1
]}

SCHNEIDER, GM ^{[1
]}

机构：

[1] UNIV BOCHUM,INST PHYS CHEM,BOCHUM,FED REP GER

来源：

BERICHTE DER BUNSEN-GESELLSCHAFT-PHYSICAL CHEMISTRY CHEMICAL PHYSICS | 1976年 / 80卷 / 09期

关键词：

Thermoanalysis;

D O I：

10.1002/bbpc.19760800913

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

The phase transition temperature solid/nematic (melting temperatures) and nematic/liquid isotropic (clearing temperatures) of the liquid crystals MBBA, EBBA, PBBA, PEBAB, PAA, and PAP were measured as a function of pressure up to 3 kbar and in the temperature range 273 K to 550 K. For PBBA the pressure dependence of the transition temperature smectic/nematic was additionally determined. For all compounds arising pressure causes an increase of the transition temperatures as well as an extension of the nematic range (especially for PAA and PEBAB). According to the thermal pretreatment two different melting curves were found for MBBA, EBBA and PEBAB separating the nematic liquid from a stable and a metastable solid phase repectively. The melting curves diverge slightly for MBBA and EBBA; for PEBAB, however, an intersection point can be extrapolated at about 2600 bar and 450 K.

引用

页码：886 / 891

页数：6

共 27 条

[1]

ARNOLD H, 1964, Z PHYS CHEM-LEIPZIG, V226, P146

[2]

BARRALL EM, 1964, J PHYS CHEM, V68, P2801

[3] The paraazoxyphenetol dilation and the nature of phase changing, isotropic mesomorph-liquid state [J].