Design and investigation of de Vries liquid crystals based on 5-phenyl-pyrimidine and (R,R)-2,3-epoxyhexoxy backbone

S. P. Sreenilayam, D. Rodriguez-Lojo, V. P. Panov, V. Swaminathan, J. K. Vij, Yu P. Panarin, E. Gorecka, A. Panov, P. J. Stevenson

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

Calamitic liquid crystals based on 5-phenyl-pyrimidine derivatives have been designed, synthesized, and characterized. The 5-phenyl pyrimidine core was functionalized with a chiral (R,R)-2,3-epoxyhexoxy chain on one side and either siloxane or perfluoro terminated chains on the opposite side. The one involving a perfluorinated chain shows SmA∗ phase over a wide temperature range of 82 °C, whereas the siloxane analog exhibits both SmA∗ and SmC∗ phases over a broad range of temperatures, and a weak first-order SmA∗-SmC∗ transition is observed. For the siloxane analog, the reduction factor for the layer shrinkage R (relative to its thickness at the SmA∗-SmC∗ transition temperature, TAC) is ∼0.373, and layer shrinkage is 1.7% at a temperature of 13 °C below the TAC. This compound is considered to have "de Vries smectic" characteristics with the de Vries coefficient CdeVries of ∼0.86 on the scale of zero (maximum-layer shrinkage) to 1 (zero-layer shrinkage). A three-parameter mean-field model is introduced for the orientational distribution function (ODF) to reproduce the electro-optic properties. This model explains the experimental results and leads to the ODF, which exhibits a crossover from the sugar-loaf to diffuse-cone ODF some 3 °C above TAC.

Original languageEnglish
Article number042701
Number of pages13
JournalPhysical Review E
Volume96
Issue number4
DOIs
Publication statusPublished - 03 Oct 2017
Externally publishedYes

ASJC Scopus subject areas

  • Statistics and Probability
  • Condensed Matter Physics
  • Statistical and Nonlinear Physics

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