Bent-core mesogens - substituent effect and phase behavior [Elektronische Ressource] / von Hajnalka Nádasi

BENT-CORE MESOGENS – SUBSTITUENT EFFECT AND PHASE BEHAVIOR DISSERTATION zur Erlangung des akademischen Grades doctor rerum naturalium (Dr. rer. nat) vorgelegt der Mathematisch-Naturwissenschaftlich-Technischen Fakultät (mathematisch-naturwissenschaftlicher Bereich) der Martin-Luther-Universität Halle-Wittenberg von Frau Dipl.- Chem. Hajnalka Nádasigeboren am 14.08.1975 in Budapest Gutachter 1. Prof. Wolfgang Weissflog 2. Prof. Gerhard Pelzl 3. Dr. Katalin Fodor-Csorba Halle (Saale), den 06. 05. 2004 urn:nbn:de:gbv:3-000007274[http://nbn-resolving.de/urn/resolver.pl?urn=nbn%3Ade%3Agbv%3A3-000007274]To the memory of my grandfather Table of Contents Chapter 1 Introduction 1 1.1 Bent-shaped mesogens: a topic area of liquid crystals 11.1.1 Structure of bent-core mesogens 1 1.1.2 Structure of liquid crystalline phases of bent-shaped molecules 3 1.1.3 Experimental techniques 4 1.2 This thesis 5Chapter 2 The field of bent-shaped mesogens 7 2.1 Mesophases of bent-shaped mesogens 72.1.1 Predicted banana mesophases 7 2.1.2 Realization of banana mesophases 9 2.2 Experimental techniques 122.2.1 Polarizing microscopy 12 2.2.2 Calorimetric studies 12 2.2.3 X-ray diffraction 13 2.2.4 Electro-optical studies 14 2.2.5 Nuclear magnetic resonance studies 16 2.2.6 Dielectric spectroscopy 18 2.3 Chemical structure-property relationships in bent-shaped molecules 212.3.1 The central unit 222.3.2 The connecting groups 23 2.3.3 Lateral substitution 26 2.