Effect of temperature and counterion on the micelle formation process studied by positron annihilation techniques
The positron annihilation technique was applied to the study of the micelle formation process in micellar systems Aerosol OT and dodecylammonium propionate (DAP) in apolar solvents, such as benzene and isooctane. At certain surfactant concentrations abrupt changes in the number of thermal o-Ps atoms formed can be observed. The surfactant concentration at which this effect can be seen is widely temperature independent in Aerosol OT solutions while a significant shift to higher surfactant concentrations can be found with increasing temperature in DAP solutions. The effect of the nature of the counterion on the mechanism of micelle formation is further investigated by substituting the counterion Na/sup +/ in Aerosol OT by tetraalkylammonium ions, N/sup +/H/sub 4/, N/sup +/(CH/sub 3/)/sub 4/, and N/sup +/(C/sub 2/H/sub 5/)/sub 4/. The results are discussed in terms of the pseudophase model and multiple equilibrium model for micelle formation.
- Research Organization:
- Virginia Polytechnic Inst. and State Univ., Blacksburg
- OSTI ID:
- 6197199
- Journal Information:
- J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 83:19; ISSN JPCHA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400201* -- Chemical & Physicochemical Properties
AMINES
AMMONIUM COMPOUNDS
ANNIHILATION
ANTILEPTONS
ANTIMATTER
ANTIPARTICLES
BASIC INTERACTIONS
ELECTROMAGNETIC INTERACTIONS
ELEMENTARY PARTICLES
FERMIONS
INTERACTIONS
LEPTONS
MICELLAR SYSTEMS
ORGANIC COMPOUNDS
ORGANIC SOLVENTS
PHASE TRANSFORMATIONS
POSITRONS
QUATERNARY COMPOUNDS
SOLVENTS
SURFACTANTS