Swelling and dissolution of onion phases: the effect of temperature

Citation
M. Buchanan et al., Swelling and dissolution of onion phases: the effect of temperature, COLL SURF A, 183, 2001, pp. 293-302
Citations number
25
Categorie Soggetti
Physical Chemistry/Chemical Physics
Journal title
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
ISSN journal
09277757 → ACNP
Volume
183
Year of publication
2001
Pages
293 - 302
Database
ISI
SICI code
0927-7757(20010715)183:<293:SADOOP>2.0.ZU;2-Y
Abstract
Contact experiments have been performed between an onion lamellar phase and brine in the SDS/octanol/brine system. Using video microscopy we have stud ied the non-equilibrium behaviour of the swelling and dissolution process o f onions. Experiments at T = 20 and 30 degreesC showed that temperature has a strong effect on their behaviour. At low temperature onions are observed to diffuse away from the onion phase and only swell slightly. However, by increasing the temperature we induce the formation of sponge phase (L-3) at the onion/brine interface. Onions that initially swell then dissolve into L-3 phase expel a stable core which moves to the micellar phase and remains there. Over a longer period of time (several days) we have also observed c oalescence leading to the formation of large onions of up to similar to 100 mum diameter. These huge onions have a radial distribution of domains, or solvent cavities, within them. (C) 2001 Elsevier Science B.V. All rights re served.