Simulation insights into the role of antiparallel molecular association in the formation of smectic A phases

Walker, Martin; Wilson, Mark R.

Abstract

A simple dissipative particle dynamics (DPD) model is introduced, which can be used to represent a broad range of calamitic mesogens. The model allows for antiparallel association that occurs naturally in a number of mesogens with terminal dipoles, including the 4-n-alkyl-4′-cyanobiphenyl (nCB) series. Favourable antiparallel interactions lead to the formation of SmAd phases in which the layer spacing is intermediate between monolayer and bilayer. The model is easily tuned to vary the strength of antiparallel association and the SmA layer spacing, and to give either isotropic–smectic or isotropic–nematic–smectic phase sequences. The model allows for a range of other smectics: including SmA1 phases exhibiting microphase separation within layers, and smectics A structures with more complicated repeat units. For large system sizes (≥50 000 molecules) in the nematic phase, we are able to demonstrate the formation of three distinct types of cybotactic domains depending on the local interactions. Cybotactic domains are found to grow in the nematic–smectic pretransitional region as the system moves closer to TSN.

Citation

Walker, M., & Wilson, M. R. (2016). Simulation insights into the role of antiparallel molecular association in the formation of smectic A phases. Soft Matter, 12(43), 8876-8883. https://doi.org/10.1039/c6sm01920j

• Journal Article Type: Article
• Acceptance Date: Sep 29, 2016
• Online Publication Date: Sep 29, 2016
• Publication Date: Nov 21, 2016
• Deposit Date: Oct 7, 2016
• Publicly Available Date: Sep 29, 2017
• Journal: Soft Matter
• Print ISSN: 1744-683X
• Electronic ISSN: 1744-6848
• Publisher: Royal Society of Chemistry
• Peer Reviewed: Peer Reviewed
• Volume: 12
• Issue: 43
• Pages: 8876-8883
• DOI: https://doi.org/10.1039/c6sm01920j
• Public URL: https://durham-repository.worktribe.com/output/1395740