Impact of local inhomogeneities on the complexation between poly(diallyldimethylammoniumchloride) and sodium dodecyl sulfate

Self-Consistent Mean Field Calculations of Polyelectrolyte-Surfactant Mixtures in Solution and upon Adsorption onto Negatively Charged Surfaces

“…The most important drawback which restricts the progress of the understanding of the behavior of polyelectrolyte-surfactant mixtures is the strong controversy associated with the physico-chemical nature of the complexes formed in solution: equilibrium versus kinetically-arrested states [14][15][16][17][18][19][20][21][22][23]. It is worth mentioning that recent studies have suggested that the nature of the complexes may be related to the incorporation of counterions within the aggregates, with their absence favoring the formation of equilibrium complexes [24][25][26].…”

“…The formation of such kinetically trapped aggregates is the result of local surfactant concentration gradients (Marangoni stresses) that lead to the formation of compact aggregates, with a core which is supposed to be neutral, even though their net charge remains undercompensated [22,38,39]. Thus, such aggregates remain dispersed in the aqueous medium, with their sedimentation being slower than that corresponding to the true equilibrium complexes [18,19,38].…”

Determination of SLES in Personal Care Products by Colloid Titration with Light Reflection Measurements

“…Adding sodium chloride in a concentration of 40 mM decreased determination recovery to 93% ( Figure 6 a). The adverse effect of sodium chloride on the binding of SDS anions to polyDADMAC cations is well known [ 17 , 26 , 27 ]. Its mechanism is the electrostatic shielding of both the organic ions by inorganic counterions.…”

“…Sodium chloride in concentrations 100–200 mM leads to a substantial decrease in SDS association with polyDADMAC (at SDS concentration 0.1–1 mM [ 26 ] and 4–6 mM [ 27 ]). At a sodium chloride concentration equal to 200 mM and SDS concentration equal to 0.5–8 mM, no stable colloidal dispersion was observed [ 17 ]. Citric acid has a milder interfering effect than sodium chloride ( Figure 6 b).…”

“…The main role it plays is electrostatic attraction due to a high cationic charge density on polyDADMAC macromolecules. Alongside this, hydrophobic interaction provides a secondary association resulting in the formation of various globular architectures [ 13 , 16 , 17 , 18 ]. In general, hydrophobic interaction and secondary aggregation increase with the increase of the hydrophobic chain length in the surfactant molecule [ 19 ].…”