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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-22 1:31 |
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Conference: Bucharest University Faculty of Physics 2011 Meeting
Section: Polymer Physics
Title:
Electro-optical properties of disperse systems with anisotropic fluid
Authors:
F. M. ION
Affiliation:
Faculty of Physics, University of Bucharest
E-mail
ionflorinmarius@yahoo.com
Keywords:
electro-optical, dispersed liquid crystal system, nanotubes, singlewall nanotube, multi-wall nanotube
Abstract:
There were studied the electro-optical properties of a dispersed liquid crystal system – nanotubes
E7 (Merck)
- mesophase in the range between 20 °C and 61 °C
- dielectric anisotropy between 13.8 to 20 °C
- refractive index n = 1.6
- singlewall nanotube (SWNT)
- multi-wall nanotube (MWNT) CN3017-Seedchem
The tube diameter is 20-30 nm, wall thickness 1-2 nm, tube length 0,5-2 m.
Particular problems arising in such systems are related to the tendency of clustering of nanotubes:
- singlewall nanotube (SWNT) form clusters
- multi-wall nanotube (MWNT) form fibrils
This trend is accelerated by temperature and is independent of cell thickness. Note the clear tendency of the fibrils in the same direction. We observed no dependence on the concentration of nanotubes(in conditions c< 0.05%.).
To obtain a homogeneously dispersed system to assess the electro-optical properties we used the ultrasonic classical technique. Thuse, the mixture is dispersed by ultrasonic 40-45KHz (30-50Watt) for 1- 2 hours at a temperature as close as possible to the nematic isotropic transition.
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