Surface-induced orientational order in the isotropic phase of a liquid-crystal material

Crawford, G. P.; Stannarius, Ralf; Doane, J. William

doi:10.1103/physreva.44.2558

Cited by 128 publications

(82 citation statements)

References 27 publications

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“…The mosaïcity is about 30 degrees, which is too large to be attributed to the angular distribution of the channel axis, which are straight and parallel to each other up to the macroscopic scale. The alignment results from a combination of the dimensionality of the porous volume and the anchoring conditions induced at the solid interface [30,31,32]. Most probably, the case of PSi does not reflect fluctuations of the uniaxial character of the porous topology but rather some pore surface irregularities.…”

Section: Discussionmentioning

confidence: 99%

Rich polymorphism of a rod-like liquid crystal (8CB) confined in two types of unidirectional nanopores

et al. 2008

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We present a neutron and X-rays scattering study of the phase transitions of 4-n-octyl-4'-cyanobiphenyl (8CB) confined in unidirectional nanopores of porous alumina and porous silicon (PSi) membranes with an average diameter of 30 nm. Spatial confinement reveals a rich polymorphism, with at least four different low temperature phases in addition to the smectic A phase. The structural study as a function of thermal treatments and conditions of spatial confinement allows us to get insights into the formation of these phases and their relative stability. It gives the first description of the complete phase behavior of 8CB confined in PSi and provides a direct comparison with results obtained in bulk conditions and in similar geometric conditions of confinement but with reduced quenched disorder effects using alumina anopore membranes.

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Section: Discussionmentioning

confidence: 99%

Rich polymorphism of a rod-like liquid crystal (8CB) confined in two types of unidirectional nanopores

et al. 2008

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“…Here there is surface induced order in the isotropic phase which has been the subject of several detailed investigations [61]. In this system the two isotopes of xenon give two separate experimental observables of the ordering that would be interesting to compare to theoretical predictions.…”

Section: A)mentioning

confidence: 99%

Applications of highly spin-polarized xenon in NMR

Long

1993

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“…Likewise, solid substrates may induce orientational ordering at temperatures above the bulk clearing point (see e.g. [75,76] and references therein). The observation of such ordering phenomena in thin layers and detailed structure assessment are conveniently performed in freely suspended films, which provide large, molecularly flat surfaces.…”

Section: Introductionmentioning

confidence: 99%

Surfaces and Interfaces of Free-Standing Smectic Films

Schüring¹,

Stannarius²

2004

Molecules in Interaction With Surfaces and Interfaces

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Abstract. Free-standing smectic films are unique fluid objects with an exceptionally large surface-to-volume ratio. They are excellently suited for studies of surface and interface properties of liquids. We describe surface tension measurements in the smectic and isotropic phases, with particular emphasis on anomalies near the phase transitions. A model that considers the excess surface entropy of ordered surface layers is applied to describe the experimental observations qualitatively and quantitatively. From the geometrical properties of isotropic droplets in free-standing films and from the forces acting on these droplets, interface tensions between the smectic and isotropic phases are derived. Finally, we report measurements of the gas permeation through smectic films and develop a model for the description of the film-thickness dependence of the permeation coefficient.

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Surface-induced orientational order in the isotropic phase of a liquid-crystal material

Cited by 128 publications

References 27 publications

Rich polymorphism of a rod-like liquid crystal (8CB) confined in two types of unidirectional nanopores

Rich polymorphism of a rod-like liquid crystal (8CB) confined in two types of unidirectional nanopores

Applications of highly spin-polarized xenon in NMR

Surfaces and Interfaces of Free-Standing Smectic Films

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