Exploiting Molecular Symmetry Reduction to Enrich Liquid Crystal Phase Diversity

Peer reviewed: 
Yes, item is peer reviewed.
Scholarly level: 
Faculty/Staff
Final version published as: 

David F. Ester & Vance E. Williams (2019) Exploiting molecular symmetry reduction to enrich liquid crystal phase diversity, Liquid Crystals, DOI: 10.1080/02678292.2019.1575991 

https://doi.org/10.1080/02678292.2019.1575991

Date created: 
2019-02-17
Identifier: 
DOI: 10.1080/02678292.2019.1575991
Keywords: 
Liquid crystals
Phase transitions
Symmetry
Abstract: 

The strategic tuning of liquid crystalline phase behaviour by adjusting molecular symmetry was investigated. A family of sixteen symmetrical and unsymmetrical 2,6-di(4’-n-alkoxybenzoyloxy) naphthalene derivatives were prepared and their liquid crystal properties examined by differential scanning calorimetry, polarised optical microscopy, and x-ray diffraction. All mesogens formed nematic phases, with longer-chain analogues also exhibiting smectic C phases at lower temperatures. Melting temperatures of the compounds strongly depend on molecular symmetry, whereas clearing transitions are relatively insensitive to this effect. A detailed analysis indicates that the clearing point can be predicted based on the nature of the terminal alkyl chains, with only a secondary effect from molecular symmetry. Moreover, low symmetry molecules showed a greater tendency to form smectic C phases, which was ascribed to the selective depression of the melting point versus the SmC-N transition. This demonstrates that molecular symmetry-breaking is a valuable tool both for tuning liquid crystalline phase range and for increasing a material’s polymorphism.

Description: 

The fulltext of this paper and supplementary material will be available in March 2020 in keeping with the 12 month embargo policy of the journal Liquid Crystals and the publisher Taylor and Francis. 

If you require access to the fulltext before this time please contact summit@sfu.ca

Language: 
English
Document type: 
Article
Rights: 
Rights remain with the authors.
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