Please use this identifier to cite or link to this item: http://hdl.handle.net/2289/5793
Title: Electric-field-induced switchable dark conglomerate phases in a bent-core liquid crystal exhibiting reverse columnar phases.
Authors: Deepa, G.B.
Radhika, S.
Sadashiva, B.K.
Pratibha, R.
Issue Date: Jun-2013
Publisher: American Physical Society
Citation: Physical Review E, 2013, Vol.87, p062508
Abstract: Electric-field-induced transitions into switchable dark conglomerate (DC) phases from two types of reverse columnar mesophases have been observed in the bent-core (BC) compound 2,7-naphthylene bis[4-(3-methyl-4-n-tetradecyloxybenzoyloxy)] benzoate. Optical and x-ray studies show that the higher temperature columnar phase corresponds to the orthogonal B1rev phase, whereas the lower temperature columnar phase is a variant of the B1revtilt phase. As the layer fragments in this phase are modulated in order to relieve the steric hindrance caused by an anticlinic tilting in adjacent blocks, it has been named B1revtiltM. The shape of the chiral domains are different in the DC phases viz. DC-B1rev and DC-B1revtiltM obtained by applying the electric field in the B1rev and B1revtiltM phases, respectively. While the chiral domains in the DC-B1rev phase appear similar to those observed in other DC phases, the shape of the domains in the DC-B1revtiltM phase appear to have some similarity to the domains in the banana leaf texture in the B1revtiltM phase implying that the detailed structure in this DC phase may be different. Optical observations, electro-optics, and dielectric studies show that the DC-B1rev and DC-B1revtiltM phases are both switchable and possess a local SmCSPF type of structure. As the temperature is decreased the switching behavior changes from ferroelectric to antiferroelectric. The temperature at which this changeover starts occurring coincides with the temperature at which the layer modulation occurs to overcome anticlinic tilt and the B1rev to B1revtiltM phase transition takes place without the application of the electric field. The change in switching behavior is attributed to a transformation into flat layers with the SmCAPA type of structure as also evidenced by the nucleation of bright regions alongside the chiral domains.
Description: Open Access
URI: http://hdl.handle.net/2289/5793
ISSN: 1550-2376 (Online)
1539-3755
Alternative Location: http://dx.doi.org/ 10.1103/PhysRevE.87.062508
http://adsabs.harvard.edu/abs/2013PhRvE..87f2508D
Copyright: 2013 American Physical Society
Appears in Collections:Research Papers (SCM)

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