Swelling of ionic and nonionic surfactant micelles by high pressure gases.
The influence of different solvent environments on the size, shape, and characteristics of surfactant micelles of Pluronic F127 and CTAB was investigated by small-angle neutron scattering (SANS). SANS experiments were undertaken on dilute micellar surfactant solutions of F127 and CTAB that between them were exposed to liquid and supercritical carbon dioxide, liquid propane, ethane, and heptane under various pressures and temperatures. Swelling of the surfactant micelles could be directly related to the solubility of the solvents within the micelles, especially within their cores. Carbon dioxide produced the largest swelling of the Pluronic F127 micelles, compared to propane and ethane, which mirrors the solubility of the gases in the PPO core of the micelles. Conversely, the extent of swelling of the cores of CTAB micelles was greater with propane compared to carbon dioxide, which again relates to the solubility of the solvents in the alkane core of the CTAB micelles.
Materials and Supercritical Fluids Group, Department of Chemistry, Tyndall National Institute, University College Cork, Cork, Ireland.
John M
JM
O'Callaghan
Hugh
H
McNamara
Mark P
MP
Copley
John P
JP
Hanrahan
Michael A
MA
Morris
David C
DC
Steytler
Richard K
RK
Heenan
Justin D
JD
Holmes
D000077286:Cetrimonium; D002593:Cetrimonium Compounds; D005740:Gases; D007477:Ions; D008823:Micelles; D020442:Poloxamer; D011312:Pressure; D013501:Surface-Active Agents
D002593:Cetrimonium Compounds; D005740:Gases; D007477:Ions; D008823:Micelles; D013501:Surface-Active Agents; D020442:Poloxamer; D000077286:Cetrimonium