Surfactant binding and micellisation in polymer solutions and gels: binding isotherms and their consequences

Abstract

Transient networks are formed by many pairs of polymer and surfactant that associate into mixed micelles. Generally, for a given polymer concentration, the viscosity or the elastic shear modulus of such mixtures first increases and then decreases with the concentration of added surfactant. We point to the importance of considering the general features of the isotherm for the binding of the surfactant to the polymer when analysing these effects. We argue that a break-down of mixed micellar crosslinks between polymers should typically occur only when the added surfactant dominates in the mixed micelles. At this point, the concentration of monomeric surfactant should be of the same order as the relevant c.m.

Controlled Drug Release from Gels Using Lipophilic Interactions of Charged Substances with Surfactants and Polymers

“…4) where rheological measurements show that G is larger than for the pure gel, not only for the 18 mM alprenolol concentration as discussed above, but also for the gels with concentrations of 4.5 and 9 mM. Owing to its amphiphilic properties, alprenolol can probably assist in the formation of micelle-like structures containing the lipophilic modifications of C1342 as has been shown with surfactants (23). These aggregates may explain the increased gel strength in the presence of alprenolol.…”

Controlled drug release from gels using surfactant aggregates: I. Effect of lipophilic interactions for a series of uncharged substances

“…This phenomenon has been seen, for example, for hydrophobically modi®ed EHEC and SDS mixtures. 31 The high G H with no frequency dependence and the low G H in Figure 4b (phase angle`108) indicate that the gel structure was not lost in any of the formulations.…”

Viscosity Effects of a Graft Copolymer with a Hydrophobic Backbone and Hydrophilic Side Chains in a Water/AOT/Cyclohexane Oil-Continuous Microemulsion

“…The HMWSP also interact strongly with surfactants. [2][3][4][5][6][7][8][9][10][11][12] Surfactant addition often gives rise to a great increase of the viscosity, and the rheology is very sensitive to the surfactant-to-polymer ratio. The viscosity enhancement is due to cross-linking of the polymer chains by mixed micelles formed by the surfactant molecules and the hydrophobic side chains of the polymer.…”