Organic counterions and micellar parameters: substituent effects in a series of benzoates

Effects of chemical structures of para-halobenzoates on micelle nanostructure, drag reduction and rheological behaviors of dilute CTAC solutions

“…Generally, there are two basic types/locations of binding: interfacial (Stern layer) binding, driven by prevailing electrostatic forces which are predominant for small inorganic counterions such as Cl − , Br − and penetrating (micelle core) binding, driven by prevailing hydrophobic forces which are predominant in large organic counterions such as salicylate or naphthoate. While interfacial counterion binding can generally stabilize micelles and lower their CMC to some extent, penetrating counterion binding can greatly promote micellar growth and induce morphological change (spherical to threadlike and further to vesicles) at much lower concentrations [21]. Counterion to surfactant molar concentration ratio, ξ, is an important factor affecting DR ability, rheological properties and nanostructures of DR ionic surfactant solutions [22][23][24][25].…”

Self-assembly and influence of the organic counterion in the ternary systems dodecylamine/acrylic acid/water and dodecylamine/methacrylic acid/water

“…It is also well known that the presence of an organic counterion reduces the CMC compared to more hydrophilic inorganic counterions. Several studies have been devoted to determining the role played by organic counterions in the surfactant properties of diverse systems [3][4][5][6][7][8][9][10][11][12][13][14][15][16]. The hydrophobicity of organic counterions may promote a higher degree of binding onto the micelle surface [11][12][13]17,18], and can even cause a change in the shape of the micelles [14].…”

Occurrence of shear thickening in aqueous micellar solutions of CTAB with some added organic counterions

“…NMR spectroscopy [16] has revealed that when C , 1 4C !2 (R"C 1 /C " 41), almost all NaSal dissociate and Sal\ ions form complexes with CTA> to form thread-like micelles. Salicylate inserts its benzene ring into the hydrophobic part of the micelle as an intercalation of the salicylate between RTA> molecules [9,17,18]. For tosylate, Bunton et al [19] found that the viscosity of a solution of CTAB increases very markedly when NaTos is added.…”