Experimental investigation of phase transitions exhibited by symmetric liquid crystal dimers

✍ Scribed by B. Gogoi; T. K. Ghosh; P. R. Alapati

• Publisher: John Wiley and Sons
• Year: 2005
• Tongue: English
• Weight: 112 KB
• Volume: 40
• Category: Article
• ISSN: 0232-1300
• DOI: 10.1002/crat.200410413

✦ Synopsis

As a part of our systematic study of phase transitions in liquid crystal dimers we report here the variation of density across the phase transitions Isotropic -Smectic A and Smectic A -Smectic F exhibited by the Schiff base liquid crystal dimeric compounds of α,ω-bis(4-alkylanilinebenzylidene-4′-oxy)alkane (m.OnO.m) homologous series. The compounds studied are 6.O5O.6 and 6.O6O.6. The compound 6.O5O.6 exhibits only Smectic A phase, whereas the compound 6.O6O.6 exhibits Smectic A and Smectic F phases. The density jumps and peak in thermal expansion coefficient at the transitions confirm the first order nature of the transitions with a smaller density jumps compared to the monomeric liquid crystals. The calculated pressure dependance of the transition temperatures using Clauasius-Clapeyron equation is also reported.