Cryogenic Transmission Electron Microscopic Studies of Micellar Structure Correlated with Solution Viscosity on Perfluorooctyl Sufonates and Their Mixtures with a Nonionic Surfactant

H and 19F NMR Study of the Counterion Effect on the Micellar Structures Formed by Tetraethylammonium and Lithium Perfluorooctylsulfonates. 1. Neat Systems

“…Here, k B is the Boltzmann constant, T is the temperature (303 K), η is the solvent viscosity (9.73 × 10 -4 N s m -2 ), R is the micellar radius (1.50-1.75 nm) obtained from the cryo-TEM, 2 and f is a dimensionless boundary condition factor for the friction coefficient. Equation 12 with f ) 6 is expected to be applicable for sufficiently large uncharged spheres.…”

The critical micelle concentration of tetraethylammonium perfluorooctylsulfonate in water

“…Ionic perfluorosurfactants form spherical or threadlike micelles in water, depending on the nature of the counterion and the concentration of added electrolyte [3]. In particular, alkylammonium counterions are known to induce the transition from spherical to threadlike micelles in a series of perfluorosulfonic and -carboxylic acids, producing a high solution viscosity [4]. Perfluorooctanesulfonate (PFOS) salts or compounds that may degrade to PFOS have been employed since a long time ago in common uses and industrial formulations, such as fabric treatments, antistatic agents, paper coatings approved for food contact, shampoos, corrosion inhibitors, insecticides, and firefighting foams (AFFs) [5,6].…”

Linear Viscoelastic Behavior of Perfluorooctyl Sulfonate Micelles Stabilized with Tetraethylammonium and Tetramethylammonium Cations

“…[1][2][3][4][5][6] Among these aggregates, threadlike micelles exhibiting prominent viscoelasticity have been subjected to extensive rheological studies. [7][8][9][10][11][12][13][14][15] The stress of the threadlike micelles is related to their orientation/stretching, as in the case of unbreakable polymer chains.…”

“…A different type of threads is formed in aqueous solutions of tetraethylammonium (TEA) perfluorooctyl sulfonate (FOS): For these solutions, cryogenic transmission electron microscopy (cryo-TEM) revealed that the FOS molecules aggregate into spherical micelles (with the fluorooctyl groups inside) and these micelles associate with each other to form pearl-necklace shaped threads. 5,6,16,17) These FOS threads, further organized into dendritic networks, exhibit the Maxwell-type terminal relaxation in the linear viscoelastic regime. 16,17) This linear relaxation behavior, being attributed to the thermal scission of the FOS threads, is qualitatively similar to that of the CTAB:NaSal threads, 11,12) although the * To whom correspondence should be addressed.…”

“…For the FOSTEA solution, cryo-TEM confirmed that spherical FOS micelles were connected into threads and further organized into dendritic networks. The bare radius of the spherical FOS micelles (not including the TEA radius), was r FOS ≅ 1.6 nm, 5,16) and each micelle is composed of ≅ 16 FOS units. 18) This r FOS value was close to that estimated from the packing structure of the perfluorooctyl groups in the micelle, and r FOS hardly changed in the presence of other cations (Li).…”