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EPR of the Sodium Laurate-Water Lyotropic Mesophases and Micellar Solution

M. Schara ; J. Stefan Institute, University .of Lj·ubljana, Ljubljana, Yugoslavia
F. Pušnik ; J. Stefan Institute, University .of Lj·ubljana, Ljubljana, Yugoslavia
M. Šentjurc ; J. Stefan Institute, University .of Lj·ubljana, Ljubljana, Yugoslavia

Sažetak

The local orienta>tional order of molecules in lameilar and
hexagonal mesophases as well as in micellar aggregates of the
sodium laurate - water system was studied by EPR. As a paramagnetic
probe a fatty acid spin label, dissolved in the hydrophobic
environment was used.
1t was found that the ordering parameter decreases cont1nously
over the whole concentration and temperature range of
the mesophases irrespective of the phase transitions.
From the local ordering parameter observed in cylindrical
micelles, the variation of cylinder dimensions with tempeirature
and concentration was estimated. In the micellar solution the concentration range where cylindrical micelles were the most stable
was determined, and its relation to the maximal stab.ility region in
the hexagonal phase was discussed.
The rate of molecular tumbling around the cylindrical axes in
the hexagonal phase was found faster t han 108 sec-1 at 100 °c.

Ključne riječi

Hrčak ID:

196476

URI

https://hrcak.srce.hr/196476

Datum izdavanja:

30.4.1976.

Posjeta: 621 *