This article will review some of our recent work concerning the relationships between molecular structure and the observation of the fascinating twist-bend nematic, NTB, phase. From a chemist’s perspective, understanding the molecular features influencing the formation and stabilisation of the NTB phase is of paramount importance, and allows for the design of new materials that have targeted properties. As such, recent work in Aberdeen has had the primary aim of enhancing our current understanding of these relationships in dimeric liquid crystals, through the synthesis and characterisation of a diverse range of materials, including a selection of supramolecular liquid crystals. A second aim has been to explore the intriguing question as to how the NTB phase, having spontaneous structural chirality, would respond at a microscopic level to the presence of intrinsic molecular chirality – the inclusion of chiral fragments in the dimers – and to obtain examples of the ‘chiral’ twist-bend nematic phase (N*TB) for comparative study alongside the conventional NTB phase. We also show that bent achiral molecules form heliconical smectic phases, as predicted by Dozov in his seminal 2001 work.
I would like to firstly thank Professor Corrie Imrie for ongoing mentorship, encouragement and many invaluable discussions on the twist-bend phases. I thank Professor Ewa Gorecka and Dr Damian Pociecha for welcoming me into their laboratory in Warsaw for many fruitful research visits, and for lengthy discussions on my materials. I also thank current and former colleagues who have been involved in this work: Professor John Storey, Dr Peter Henderson, Dr Alfonso Martinez-Felipe, Daniel Paterson, Jordan Abberley and Ewan Forsyth; former project students Gaynor Lawrence, Catriona Crawford and Ross Killah; and collaborators at the Universities of Warsaw, Maribor, Kent State and the Lawrence Berkeley National Laboratory for their contributions to these projects. Lastly, I would like to thank the Carnegie Trust for the Universities of Scotland for awards of Vacation (2014) and PhD Scholarships (2015-2018) during which the bulk of this work was completed, and the Royal Society of Chemistry for the award of a Mobility Grant to visit the University of Warsaw.
- liquid crystal dimers
- twist- bend nematic phase
- structure-property relationships
- hydrogen- bonding