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Order parameter studies on EPAP alkanoate mesogens
- Source :
- Liquid Crystals. 39:295-301
- Publication Year :
- 2012
- Publisher :
- Informa UK Limited, 2012.
-
Abstract
- The refractive indices of p(p-ethoxyphenylazo) phenyl (EPAP) alkanoates, which are the nematic liquid crystals where the alkyl chain n is 5, 6, 7 and 11, were measured as a function of temperature at λ = 6328 A using a wedge technique. The temperature variation of the orientational order parameter (S) is calculated at this wavelength using the Vuks model (with consideration of internal field) and by different methods excluding the internal field – Haller and Kuczynski models, and involving effective geometry parameter (αg). The intensity of light deflection in a uniaxial EPAP alkanoate with a particular molecular configuration and ordering by varying temperature is discussed. The temperature gradients of the ordinary (∂no /∂T) and extraordinary (∂ne /∂T) refractive indices are analysed. Due to a high clearing temperature with low molecular chain length, EPAP valerate exhibited low deviation of light with a large positive value of ∂no /∂T.
- Subjects :
- chemistry.chemical_classification
Birefringence
Materials science
Field (physics)
business.industry
Thermodynamics
General Chemistry
Molecular configuration
Condensed Matter Physics
Wedge (geometry)
Wavelength
Optics
chemistry
Liquid crystal
General Materials Science
business
Refractive index
Alkyl
Subjects
Details
- ISSN :
- 13665855 and 02678292
- Volume :
- 39
- Database :
- OpenAIRE
- Journal :
- Liquid Crystals
- Accession number :
- edsair.doi...........16527f65b4846224dee2fd73d0980199