Dielectric spectroscopy of liquid crystalline dispersions

Pradeep K. Rai; Morton M. Denn; Boris Khusid

doi:10.1021/la053489o

Dielectric spectroscopy of liquid crystalline dispersions

Pradeep K. Rai, Morton M. Denn, Boris Khusid

Chemical and Materials Engineering

Research output: Contribution to journal › Article › peer-review

9 Scopus citations

Abstract

We describe dielectric spectroscopy measurements on dispersions of two thermotropic liquid crystals (5CB and 8CB) in a poly(dimethylsiloxane) matrix. 5CB exhibits nematic and Isotropic phases, while 8CB exhibits smectic, nematic, and Isotropic phases. The spectra of the dispersions exhibit a temperature-dependent dielectric relaxation in the interval from 100 to 1000 Hz, with relaxation times that depend strongly on whether the dispersed phase is Isotropic, nematic, or smectic. The dielectric relaxation times also depend on the viscosity of the matrix fluid. These results suggest a coupling between the electric field and the mechanics of the interface that affects the spectrum of the dispersed phase and shifts the Maxwell-Wagner interfacial polarization peak.

Original language	English (US)
Pages (from-to)	2528-2533
Number of pages	6
Journal	Langmuir
Volume	22
Issue number	6
DOIs	https://doi.org/10.1021/la053489o
State	Published - Mar 14 2006

All Science Journal Classification (ASJC) codes

Condensed Matter Physics
Spectroscopy
General Materials Science
Surfaces and Interfaces
Electrochemistry

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10.1021/la053489o

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abstract = "We describe dielectric spectroscopy measurements on dispersions of two thermotropic liquid crystals (5CB and 8CB) in a poly(dimethylsiloxane) matrix. 5CB exhibits nematic and Isotropic phases, while 8CB exhibits smectic, nematic, and Isotropic phases. The spectra of the dispersions exhibit a temperature-dependent dielectric relaxation in the interval from 100 to 1000 Hz, with relaxation times that depend strongly on whether the dispersed phase is Isotropic, nematic, or smectic. The dielectric relaxation times also depend on the viscosity of the matrix fluid. These results suggest a coupling between the electric field and the mechanics of the interface that affects the spectrum of the dispersed phase and shifts the Maxwell-Wagner interfacial polarization peak.",

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AU - Rai, Pradeep K.

AU - Denn, Morton M.

AU - Khusid, Boris

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N2 - We describe dielectric spectroscopy measurements on dispersions of two thermotropic liquid crystals (5CB and 8CB) in a poly(dimethylsiloxane) matrix. 5CB exhibits nematic and Isotropic phases, while 8CB exhibits smectic, nematic, and Isotropic phases. The spectra of the dispersions exhibit a temperature-dependent dielectric relaxation in the interval from 100 to 1000 Hz, with relaxation times that depend strongly on whether the dispersed phase is Isotropic, nematic, or smectic. The dielectric relaxation times also depend on the viscosity of the matrix fluid. These results suggest a coupling between the electric field and the mechanics of the interface that affects the spectrum of the dispersed phase and shifts the Maxwell-Wagner interfacial polarization peak.

AB - We describe dielectric spectroscopy measurements on dispersions of two thermotropic liquid crystals (5CB and 8CB) in a poly(dimethylsiloxane) matrix. 5CB exhibits nematic and Isotropic phases, while 8CB exhibits smectic, nematic, and Isotropic phases. The spectra of the dispersions exhibit a temperature-dependent dielectric relaxation in the interval from 100 to 1000 Hz, with relaxation times that depend strongly on whether the dispersed phase is Isotropic, nematic, or smectic. The dielectric relaxation times also depend on the viscosity of the matrix fluid. These results suggest a coupling between the electric field and the mechanics of the interface that affects the spectrum of the dispersed phase and shifts the Maxwell-Wagner interfacial polarization peak.

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Dielectric spectroscopy of liquid crystalline dispersions

Abstract

All Science Journal Classification (ASJC) codes

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