Stabilization of TGB Phase in the Binary Mixture of Rod-Shaped Compounds

Abstract

A miscibility study of two cholesterol based rod-shaped compounds (R1 and R2) is presented. Both the compounds possess in common enantiotropic liquid crystalline phase sequence Cr → SmA → N* → Isotropic, which is generally exhibited by cholesterol-based compounds. Additionally, one of the rod-shaped compounds (R1) possesses a twist-grain boundary (TGB) phase over a short temperature range. In the binary mixture of these two rod-shaped compounds the TGB phase was stabilized over a long temperature range compared to that in the individual molecule R1. In the binary mixture up to 20% (w/w) of compound R1 possessing the TGB phase exhibited enhancement of the temperature range of the TGB phase compared to that of individual compound R1. Further gradual increase of percentage of R1 in the binary mixture did not show any enhancement of the TGB phase compared to that of individual R1.

Keywords:

• Binary mixture
• phase diagram
• phase induction
• rod-shaped molecules
• TGB phase

Acknowledgments

We thank the DST (New Delhi) for financial assistance. Two of us are grateful (RKS and SM) to the CSIR (New Delhi) for fellowships.

Notes

Ch = Cholesteric, I = Isotropic.