Bulk and microscopic properties of surfactant-bridged hydrogels made from an amphiphilic graft copolymer

Abstract

Water-swollen hydrogels characterized by hydrophobic microdomains within an aqueous polymer network have been prepared and investigated. The microdomains consist of comicelles of sodium dodecyl sulfate (SDS) and alkyl grafts from a hydrophobically modified water-soluble polymer and form at concentrations below the critical micelle concentration of the surfactant alone. These aggregates behave like pseudo-crosslinks, bridging together many polymer molecules to form a viscoelastic network. The comicelles have the ability to solubilize water-insoluble dyes; hence, these materials may be of use in separations and controlled release processes.

Interactions between Quaternary Ammonium Surfactant Oligomers and Water-Soluble Modified Guars

“…Figure 10 also shows the variations of N tot , N HM , and N S for the HMHPG/12-3-12 system and of N S (c P ϭ 0), the value of the aggregation number in polymer-free solutions, with the 12-3-12 concentration. N HM is seen to continuously decrease, whereas N S increases, with increasing c. A similar behavior has been reported for other associating polymer/surfactant systems (40,57). At the maximum value of N tot the mixed polymer hydrophobe/surfactant aggregates contain approximately 6 hydrophobes and 19 dimeric surfactant ions (or 38 surfactant dodecyl chains).…”

Interaction of surfactants with thickeners used in waterborne paints: A rheological study

“…Sometimes there is a range of surfactant concentrations where phase separation occurs into a nonviscous supernatant and a viscoelastic hydrogel precipitate [15][16][17][18][19][20][21]. In other cases, an increase on viscoelasticity is observed when surfactant is added, up to a maximum at a surfactant concentration, followed by a catastrophic decrease of viscoelastic properties at higher surfactant concentrations [13,14,16,19,[21][22][23][24][25][26][27][28]. This behavior has been attributed to the fact that added surfactant molecules permit the formation of more hydrophobic domains and the formation of surfactantpolymer mixed micelles.…”

Interactions between anionically modified hydroxyethyl cellulose and cationic surfactants

“…The hydrophobic parts seemingly do not contribute to network formation in the resolubilization area. The discussion of a mixed micelle conformation from surfactant molecules and polymer side chains in the preprecipitation region implies a maximum in viscosity as also found for hydrophobic nonionic polymers (5,36,37). An increasing amount of surfactant molecules causes formation of more mixed micelles in which the number of involved polymer side chains decreases until a situation is reached where every side chain is covered by its own micelle.…”