Large C12TAB Micelles Formed in Complexes with Polyvinylsulfate and Dextran Sulfate

Abstract

The aggregation of alkyltrimethylammonium bromide (C"TAB) surfactants in very dilute aqueous solutions of sodium polyvinylsulfate (NaPVS) and sodium dextransulfate (NaDxS) has been investigated. The aggregation number, JVS, for the surfactant in complexes with the polyions was estimated with time-resolved fluorescence quenching. For C12TAB-NaPVS the aggregates at 50 °C are considerably larger ( -120) than free micelles, in contrast to what was found earlier (Hansson, P.; Almgren, M. Langmuir 1994M. Langmuir , 10, 2115 for complexes with sodium polyacrylate. The interaction with NaDxS also results in large micelles (Ns = 107). Binding isotherms for C12TAB in 0.5 mM NaPVS solutions at 25 and 50 °C were determined. The effect of temperature is small. The observed high cooperativity in the binding is consistent with the large aggregation number. The effect of NaDxS concentration on the cac was investigated and found to be equivalent to the effect of simple salt. The relation between intrinsic binding strength, cooperativity, and aggregation number is discussed.

Interactions between cationic starch and anionic surfactants

“…The N agg values for polyelectrolyte-bound aggregates increase with the surfactant chain length as in polymer-free systems (Almgren et al, 1992), but decrease with temperature (Hansson and Almgren, 1995) and are independent of the nature of the surfactant counterion (Hansson and Almgren, 1994) and of the added electrolyte (Hansson and Almgren, 1995). Thus, there is series of results in contrast with the behaviour of polymer-free surfactant solutions.…”

“…Almgren et al have performed extensive determinations of N agg for variety of systems (NaPSS/C n TAB and C n TAC (Almgren et al, 1992); NaPAA or NaPSS and C n TAB (Hansson and Almgren, 1994); NaPVS or NaDXS and C 12 TAB (Hansson and Almgren, 1995); NaHy and C 10 TAB or C 12 TAB (Thalberg et al, 1991 a, d). The N agg values were found to be close to those for polymer-free aggregates for PS1("=1)/C 12 TAC, NaPAA/C 12 TAB, NaHy/C 12 TAB and NA-CMA (sodium carboxyamylose)/C 16 TAB (Zhen and Tung, 1992).…”

“…Finally, the N agg values in the NaPVS/C 12 TAB and NaDXS/C 12 TAB systems were found to be larges than for pure C 12 TAB micelles. This was interpreted as due to the special nature of sulphate group (Hansson and Almgren, 1995), as similarly the nature of counterion can affect micelle aggregation number.…”

DNA-lipid systems: A physical chemistry study

“…Only recently have we started to learn about how polymers modify surfactant self-assembly structures (2,3,9,46). The first studies probing the surfactant aggregates in the concentrated phase in a phase separated polyion-surfactant system revealed by fluorescence that the aggregates are discrete and have low aggregation numbers; they are small globular, closely spherical micelles (47)(48)(49)(50). Later work has demonstrated the rich morphology possible.…”

Aggregation of Non Ionic Surfactant Igepal in Aqueous Solution: Fluorescence and Light Scattering Studies

“…An advantage with the FQ method is that n can be determined also when the micelles interact in solution [21][22][23][24][25]. This is because the method does not rely on diffusive properties.…”