The influence of molecular shape and electronic properties on the formation of the ferroelectric nematic phase.

Cruickshank, Ewan; Tufaha, Naila; Walker, Rebecca; Brown, Stevie; Gorecka, Ewa; Pociecha, Damian; Storey, John M.D.; Imrie, Corrie T.

Abstract

The synthesis and characterisation of two series of ferroelectric nematogens based on RM734 having an additional methoxy group on the central phenyl ring are reported, the 3-methoxy-4-((4-nitrophenoxy)carbonyl)phenyl 2-alkoxy-4-alkoxybenzoates (7-m-n) and the 3-methoxy-4-((3-fluoro-4-nitro-phenoxy)carbonyl)phenyl 2-alkoxy-4-alkoxybenzoates (8-m-n). In order to compare the behaviour of these series to those of the corresponding materials that do not contain the methoxy group on the central phenyl ring, we also report the synthesis and characterisation of 4-[(4-nitrophenoxy)carbonyl] phenyl 4-methoxybenzoate (11-0-1), 4-[(3-fluoro-4-nitrophenoxy)carbonyl]phenyl 4-methoxybenzoate (12-0-1) and 4-[(3-fluoro-4-nitrophenoxy)carbonyl]phenyl 2,4-diethoxybenzoate (12-2-2). Two compounds in which a lateral ethoxy chain is attached to the central ring, 3-ethoxy-4-[(4-nitrophenoxy)carbonyl]phenyl 2,4-dimethoxybenzoate (18-2-1) and 3-ethoxy-4-[(3-fluoro-4-nitrophenoxy) carbonyl]phenyl 2,4-dimethoxybenzoate (19-2-1), are also described. The behaviour of these materials shows that the relative stabilities of the ferroelectric nematic, NF, and conventional nematic, N, phases are governed by a subtle interplay of steric and electronic factors. Furthermore, the electronic factors are better understood in terms of isolated regions of electron density rather than by a single large longitudinal dipole moment. In terms of molecular shape, to observe the NF phase it appears that the molecular structure must include one or more lateral substituents that enhance molecular biaxiality and destabilise the N phase.

Citation

CRUICKSHANK, E., TUFAHA, N., WALKER, R., BROWN, S., GORECKA, E., POCIECHA, D., STOREY, J.M.D. and IMRIE, C.T. 2024. The influence of molecular shape and electronic properties on the formation of the ferroelectric nematic phase. Liquid crystals [online], 51(3), pages 401-415. Available from: https://doi.org/10.1080/02678292.2024.2304598

• Journal Article Type: Article
• Acceptance Date: Jan 2, 2024
• Online Publication Date: Jan 25, 2024
• Publication Date: Mar 31, 2024
• Deposit Date: Jan 26, 2024
• Publicly Available Date: Jan 29, 2024
• Journal: Liquid crystals
• Print ISSN: 0267-8292
• Electronic ISSN: 1366-5855
• Publisher: Taylor and Francis
• Peer Reviewed: Peer Reviewed
• Volume: 51
• Issue: 3
• Pages: 401-415
• DOI: https://doi.org/10.1080/02678292.2024.2304598
• Keywords: Ferroelectric nematic phase; Fluorine; Lateral substituents; Liquid crystals; Nematic phase
• Public URL: https://rgu-repository.worktribe.com/output/2218701
• Additional Information: This article has been published with separate supporting information. This supporting information has been incorporated into a single file on this repository and can be found at the end of the file associated with this output.