(S)-4-(2-Methylbutyl)-4′-Cyanobiphenyl (5*CB) Glass Former: Are the Crystalline Polymorphs Ordered?

Abstract

The studies performed for right-handed (S)-4-(2-methylbutyl)-4′-cyanobiphenyl glass former using calorimetry (down to 0.35 K) and spectroscopy methods are reviewed. The substance reveals isotropic and cholesteric liquid phases, glass of cholesteric phase and two crystalline polymorphs, one of which transforms to glass. Two anomalies in heat capacity below 5 K and their relation to ordering of the molecules in three solid phases are discussed.

Keywords:

• Enthalpy relaxation
• glass transition
• heat capacity
• solid state polymorphism

PACS :

• 61.43.Fs
• 64.70.Md
• 65.50.+m

Acknowledgment

We acknowledge Professor Roman Dąbrowski from Military Academy of Technology, Warsaw, for providing the 5*CB substance. Polish authors (J.K and M.M-A.) express their deep gratitude to The Research Center for Molecular Thermodynamics for invitation, great hospitality and scientific cooperation during their stay at the Osaka University.

Notes

¹In papers [14,16–19] the phase II has been called a metastable crystal, crystal I or C1 while the phase I – a stable crystal, crystal II or C2.

*Contribution No. 11 from the Research Center for Structural Thermodynamic.