Phase behavior and morphology of equimolar mixed cationic–anionic surfactant monolayers at the air/water interface: Isotherm and Brewster angle microscopy analysis

Stability enhancement effect of normal long-chain alcohols on ion pair amphiphile monolayers at the air/water interface

“…In addition, a Brewster angle microscope (BAM) (BAM2 plus, Nanofilm Technologies GmbH, Germany) was applied to obtain the images of monolayer morphology in situ with the monolayer behavior. Detailed information regarding the BAM principle and operation can be found in the literature [16,17]. Before each run, the Teflon trough (trough size 700 × 70 mm) was washed with ethanol and rinsed with purified water.…”

On the origin of the stability of foams made from catanionic surfactant mixtures

“…mixtures of cationic and anionic surfactants. 11,12 Generally speaking, such mixtures are expected to show good properties with respect to foam formation and stabilisation for three principal reasons: (i) catanionic mixtures are known to pack very efficiently at the gas/water interface, [12][13][14][15][16][17] rendering the interfaces themselves strongly viscoelastic; 13,14,[18][19][20][21][22][23] (ii) the critical micelle (or aggregation) concentration, although generally low in these strongly non-ideal mixtures, has a finite value which provides free surfactant in solution 24 and (iii) these mixtures form vesicles 25 usually considered at thermodynamic equilibrium. 26 The presence of vesicles provides bulk viscoelastic properties (ref.…”

Physicochemical studies on ion-pair amphiphiles: Solution and interfacial behaviour of systems derived from sodium dodecylsulfate and n-alkyltrimethylammonium bromide homologues

“…Different techniques have been employed to study the phase behaviours and the interfacial morphologies of the IPAs; they are epifluorescence, polarization and Brewster angle microscopy, etc. [18][19][20] Besides atomic force microscopic measurements of the transferred monolayer and Langmuir-Blodgett (LB) technique have been used to understand their microstructural information. 21,22 Although physicochemical studies have been made on the bulk as well as the interfacial properties of IPAs, still the efforts are considered fragmentary in nature.…”