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

Temperature sensitivity of wormlike micelles in poly(oxyethylene) surfactant solution: Importance of hydrophilic-group size

“…Again, this corresponds well with the variation of the steady low-shear viscosity with temperature of these systems shown in Fig. 1 and can be attributed to the difference in the head-group sizes of ChEO 15 and ChEO 30 . Discussions of these results are presented below.…”

“…Therefore, we have proceeded with the investigation of the temperature sensitivity of the rheology of the ChEO m (m = 15 and 30) micellar systems containing C 12 EO 3 and monolaurin cosurfactant, the same surfactants studied in Ref. [30]. We report our findings in this presentation.…”

“…Recently, we reported the formation of viscoelastic wormlike micellar solutions of poly(oxyethylene) cholesteryl ether surfactant having large head-group (30 ethylene oxide units) [30]. This result opens up the possibility of studying the variation of temperature sensitivity of poly(oxyethylene) surfactant wormlike micelles through changing the chain length of the poly(oxyethylene) head-group over a large range.…”

Viscosity boosting effect of added ionic surfactant in nonionic wormlike micellar aqueous solutions

“…As examples of other systems, which are in salt-free conditions, the cationic-anionic surfactant systems [13][14][15] form wormlike micelles arising from the charge neutralization at the micellar surface. Recently, wormlike micelle formation was also reported in the systems with hydrophilic ionic + lipophilic nonionic surfactant [16][17][18][19][20][21][22][23][24][25], and hydrophilic nonionic + lipophilic nonionic surfactant [22,[26][27][28][29][30][31][32][33]. Although hydrophilic surfactants are prone to form spherical or rod-like micelle in aqueous solutions due to strong repulsion between their head groups, lipophilic cosurfactants decrease the repulsion when they are incorporated in the layer; hence, the growth of wormlike micelle is induced.…”

“…Therefore, we expect an increase in viscosity in nonionic wormlike micellar solutions on increase of the surface charge. There are many works about formation of nonionic wormlike micelles by adding lipophilic surfactant such as poly(oxyethylene) alkylether, etc., to sugar surfactant [26][27][28] or poly(oxyethylene) cholesteryl ether [22,29,32,33] or polysorbate 80 [30] aqueous solutions. According to Yamamoto et al [40], the addition of the ionic surfactant SDS to the wormlike micelle solutions with sucrose hexadecanoate/poly(oxyethylene) alkylether causes a drastic increase in the viscosity.…”