Non-symmetric dimeric liquid crystals The preparation and properties of the α-(4-cyanobiphenyl-4′-yloxy)-ω-(4-<i>n</i>-alkylanilinebenzylidene-4′-oxy)alkanes

Attard, George S.; Date, Richard W.; Imrie, Corrie T.; Luckhurst, G. R.; Roskilly, S. J.; Seddon, John M.; Taylor, L.

doi:10.1080/02678299408036531

Cited by 308 publications

(87 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Thus many series of non-symmetric dimers have now been characterised and, as we shall see, this resulted in the discovery of a novel family of smectic phases [68]. Most recently, nonsymmetric dimers have been reported in which one of the two mesogenic units is assembled via hydrogen bonding [101] The most extensively characterised examples of non-symmetric dimers are the a-(4-cyanobiphenyl-4¢-yloxy)-x-(4-n-alkylanilinebenzylidene-4¢-oxy)alkanes, 13 and the acronym used to refer to this family is CBOnO.m where n refers to the number of methylene groups in the spacer and m the length of the terminal alkyl chain [68,69]. This particular family of materials was chosen, in part, because, as we have seen, the properties of the parent symmetric dimers, ie the BCBOn and m.OnO.m series, are known [18,37].…”

Section: Non-symmetric Calamitic Liquid Crystal Dimersmentioning

confidence: 99%

Liquid Crystal Dimers

Imrie

1999

Structure and Bonding

231

104

View full text Add to dashboard Cite

A liquid crystal dimer is composed of molecules containing two conventional mesogenic groups linked via a¯exible spacer. These materials show quite different behaviour to conventional low molar mass liquid crystals and in particular their transitional behaviour exhibits a dramatic dependence on the length and parity of the¯exible spacer. In this review a comprehensive overview of the relationships between molecular structure and liquid crystallinity in dimers is provided. This includes a description of the novel modulated and intercalated smectic phases exhibited by dimers.

show abstract

Section: Non-symmetric Calamitic Liquid Crystal Dimersmentioning

confidence: 99%

Liquid Crystal Dimers

Imrie

1999

Structure and Bonding

231

104

View full text Add to dashboard Cite

show abstract

“…Plot of the nematic to isotropic liquid and the nematic to smectic A (a) and smectic C (b) phase transition temperatures (°C) [35,36]. Figure 4.…”

Section: −1mentioning

confidence: 99%

“…Therefore, if we compare the results for homologous materials with odd methylene parity (bent shape shown in Figure 3) with examples of some similar materials of even parity (rod-like), we find that the relationship between the liquid to nematic phase and the nematic to smectic A phase or nematic to smectic C phase transitions for the even parity materials is not linear but randomly scattered, as shown in Figure 4(a,b) [35,36].…”

mentioning

confidence: 99%

Free volume, molecular grains, self-organisation, and anisotropic entropy: machining materials

Goodby

2017

Liquid Crystals

View full text Add to dashboard Cite

“…The compounds were synthesized following a standard procedure as discussed in literature [1,3]. The crude product was repeatedly recrystallized from ethyl acetate until the transition temperatures were found to be constant and reproducible.…”

Section: Methodsmentioning

confidence: 99%

“…This surprising observation was rationalized by proposing a novel intercalated structure for the smectic A phase exhibited by short chain lengths and the conventional interdigitated structure for long chain lengths. The driving force for the intercalated structure was considered to be mixed mesogenic unit-mesogenic unit interaction, while for the interdigitated phase, the driving force for association was thought to be electrostatic interaction between polar and polarizable cyanobiphenyl groups and the smectic phase resulted from the molecular inhomogenity produced by the long terminal chains [3].…”

Section: Introductionmentioning

confidence: 99%

Phase transition studies in mesogenic dimers

Gogoi¹,

Alapati²,

Verma³

2002

Cryst. Res. Technol.

View full text Add to dashboard Cite

Phase transition studies in mesogenic dimersSchiff base liquid crystal dimers, both symmetric and non-symmetric, in which two anisotropic groups are linked by a flexible spacer, exhibit a rich variety of smectic mesomorphism. The interest in this class of mesogens stems not only from their ability to act as model compounds for semi-flexible mainchain liquid crystal polymers but also from their quite different properties compared to conventional low molar mass liquid crystals (monomers). We report here the phase transition studies on two examples of these schiff base liquid crystal dimers using the Differential Scanning Calorimetry and density measurements as a function of temperature. The symmetric liquid crystal dimer, α,ω-bis (4-ndodecylaniline benzylidene-4′-oxy)decane (10.O12O.10) exhibits a very rare Isotropic to G transition. Where as, the non-symmetric dimer, α-(4-cyano biphenyl-4′-yloxy)-ω-(4-n-decylanilinebenzylidene-4′-oxy)decane (CB.O10O.10) exhibits a rare nematic to intercalated smectic A phase transition. The transitions studied, isotropic to nematic and isotropic to G exhibit a large density jump at the transition confirming their first order nature. Nematic to intercalated smectic A transition is found to be a second order transition whose behavior is similar to nematic to smectic A transition. Calculated values of pressure dependence of transition temperature and thermal expansion coefficient are also reported.

show abstract

Non-symmetric dimeric liquid crystals The preparation and properties of the α-(4-cyanobiphenyl-4′-yloxy)-ω-(4-n-alkylanilinebenzylidene-4′-oxy)alkanes

Cited by 308 publications

References 40 publications

Liquid Crystal Dimers

Liquid Crystal Dimers

Free volume, molecular grains, self-organisation, and anisotropic entropy: machining materials

Phase transition studies in mesogenic dimers

Contact Info

Product

Resources

About