Artykuł w czasopiśmie
Brak miniatury
Licencja
ClosedAccessDostęp zamknięty
 

Design and electro-optic investigations of de Vries chiral smectic liquid crystals for exhibiting broad temperature ranges of SmA* and SmC* phases and fast electro-optic switching

Uproszczony widok
dc.abstract.enIn this paper, we report on the design, synthesis and characterisation of two new ferroelectric liquid crystalline compounds based on using the cores of (i) 5-phenyl-pyrimidine benzene and (ii) 5-phenyl-pyrimidine benzoate terminated by achiral trisiloxane chain, and chiral (S) alkyl chain on the opposite ends of their respective mesogens. These compounds exhibit broad temperature ranges of SmA∗ and SmC∗ phases, whereas the latter exists at room temperature down to 11 °C. This is one of the desirable features of the compounds for perspective applications in devices. In both compounds, the differential scanning calorimetry shows a weak first order SmA∗-SmC∗ transition. This observation is supported by determining the critical exponent of the power law as ∼0.2 that describes the dependence of the tilt angle and the spontaneous polarization on temperature. The two compounds show excellent de Vries characteristics in terms of lower layer shrinkages in SmC∗, the maximum shrinkage in both cases is ∼1.5%. Furthermore (i) the birefringence decreases with a reduction in temperature instead of an increase in SmA∗, and (ii) a large field-induced birefringence is observed in SmA∗ close to the SmA∗-SmC∗ transition temperature, (iii) the maximum birefringence measured is much lower than that of a typical FLC material. The characteristics of these compounds when compared to a conventional/typical ferroelectric liquid crystalline mixture show that these materials surpass in performance in terms of having a (i) wider temperature range of both SmA∗ and SmC∗ phases and (ii) higher switching speed. The layer thickness in SmA∗ and SmC∗ is measured using the techniques of (a) small-angle X ray diffraction, and the (b) optical interferometry of free standing smectic films. A comparison of the results is used to determine an exceptionally useful result of the apparent tilt angle as a function of temperature in SmA∗ without the need to apply the electric field across the cell
dc.affiliationUniwersytet Warszawski
dc.contributor.authorVij, Jagdish K.
dc.contributor.authorSwaminathan, V.
dc.contributor.authorStevenson, P. J.
dc.contributor.authorRodriguez-Lojo, D.
dc.contributor.authorPanov, A.
dc.contributor.authorPanov, V. P.
dc.contributor.authorGórecka, Ewa
dc.date.accessioned2024-01-24T21:33:18Z
dc.date.available2024-01-24T21:33:18Z
dc.date.issued2020
dc.description.financePublikacja bezkosztowa
dc.description.number14
dc.description.volume8
dc.identifier.doi10.1039/C9TC04405A
dc.identifier.issn2050-7534
dc.identifier.urihttps://repozytorium.uw.edu.pl//handle/item/104591
dc.identifier.weblinkhttp://pubs.rsc.org/en/content/articlepdf/2020/TC/C9TC04405A
dc.languageeng
dc.pbn.affiliationchemical sciences
dc.relation.ispartofJournal of Materials Chemistry C
dc.relation.pages4859-4868
dc.rightsClosedAccess
dc.sciencecloudnosend
dc.titleDesign and electro-optic investigations of de Vries chiral smectic liquid crystals for exhibiting broad temperature ranges of SmA* and SmC* phases and fast electro-optic switching
dc.typeJournalArticle
dspace.entity.typePublication