Swelling of Ionic and Nonionic Surfactant Micelles by High Pressure Gases

Abstract

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.

Microstructure of supercritical CO2-in-water microemulsions: a systematic contrast variation study

“…Using high pressure SANS experiments O'Callaghan et al were able to monitor the swelling behavior of non-ionic Pluronic s F127 and cationic cetyltrimethlyammonium bromide (CTAB) micelles with scCO 2 . 48 Although a swelling of the micelles with scCO 2 was detected as the pressure was increased no bulk-like properties of the scCO 2 in the micelle core were observed.…”

Biphase Stratification Approach to Three-Dimensional Dendritic Biodegradable Mesoporous Silica Nanospheres

“…Several methods have been reported, including the hydrothermal method in aqueous media − and solvent evaporation-induced self-assembly (EISA) in nonaqueous media . It has indicated that the soft-templating approach usually needs a homogeneous reaction system, whether the soft templates are micelles assembled with surfactants or nanoemulsions constituted of surfactants and oil drops. ,− To the best of our knowledge, there were no reports about the preparation of uniform monodispersed mesoporous silica nanospheres with large center-radial pore channels in oil–water biphase stratification reaction system, which is a heterogeneous reaction occurred in the macroscopic interface.…”

Unimer suppression enables supersaturated homopolymer swollen micelles with long-term stability after glassy entrapment

“…15 Equilibrium micelle sizes are also well known to be adjustable with hydrophobic core swelling molecules. For example, organic solvents such as 1,3,5-trimethylbenzene, 16 other hydrocarbons [17][18][19][20][21][22] and even high-pressure gasses 23 can swell micelle cores. Thus, a range of micelle sizes are generally achievable from a single block polymer with a properly selected swelling agent.…”