Phase and Rheological Behavior of Surfactant/Novel Alkanolamide/Water Systems

Abstract

Phase diagrams of water; sodium dodecyl sulfate (SDS); and a new foam booster, alkanoyl-Nmethylethanolamide (C8, NMEA-8; C12, NMEA-12; C16, NMEA-16), were constructed at 25 °C. NMEA is hardly soluble in water: liquid-liquid phase separation occurs with NMEA-8, lamellar-phase formation occurs with NMEA-12, and solid precipitation occurs with NMEA-16. In the presence of a small amount of NMEA, the surfactant hexagonal phase (H1) is extended to the dilute region. In the aqueous micellar solution beyond the H1 phase, the viscosity dramatically increases and a viscoelastic solution is formed in NMEA-12 and NMEA-16 systems. The viscoelastic micellar solution formed in SDS-NMEA-12 systems follows the Maxwell model typical of wormlike micellar systems at low shear frequencies. In the SDS-NMEA-16 system, a gel-like highly viscoelastic solution is formed in the maximum-viscosity region. Rheological measurements show that the ability of NMEA to induce micellar growth increases in the following order: NMEA-8 , NMEA-12 < NMEA-16. In agreement with this result, dynamic light scattering measurements show that with an increasing mixing fraction of NMEA-12 or NMEA-16 in SDS-NMEA systems the micellar size increases, leading to the formation of wormlike micelles.

Wormlike micelles and microemulsions in aqueous mixtures of sucrose esters and nonionic cosurfactants

“…The phase behavior depicted in Fig. 1 shows similarities to systems in which viscoelastic solutions are found between hexagonal and lamellar phases [5]. …”

“…At certain concentrations, wormlike micelles overlap in transient networks, showing viscoelasticity and other interesting properties that have been extensively investigated, which opens the possibility of several applications [3]. Wormlike micelles are also formed in mixtures of cationic-anionic [4] and ionic-nonionic surfactants [5,6], among others. Ionic surfactants, however, are not always suitable for commercial products, due to their toxicity and sensibility to electrolytes.…”

Wormlike micelles in poly(oxyethylene) surfactant solution: Growth control through hydrophilic-group size variation

“…Thus, these systems are very interesting from scientific and industrial standpoints. Therefore a large amount of research employing different materials and various techniques (such as rheology, cryo-TEM, light scattering, small-angle X-ray, and neutron scattering) has been carried out to characterize these systems [2,[5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. However, most of the past and recent work is focused on ionic surfactant systems [20][21][22][23][24][25].…”

Wormlike Micelles in Mixed Amino Acid Surfactant/Nonionic Surfactant Aqueous Systems and the Effect of Added Electrolytes

“…Salt induced wormlike micelles in ionic surfactants have been widely reported [17][18][19][20] . A few papers are available in the literature on the rheological behavior of wormlike micelles in mixed system of ionic/nonionic surfactant systems [21][22][23][24][25] . Cationic surfactant in the presence of strongly binding counterions or excess salts, forms viscoelastic wormlike micelles 26,27) .…”