Investigating the effect of a simplified perfume accord and dilution on the formation of mixed-surfactant microemulsions

Abstract

Structural changes and phase analyses of a three-PRM accord in sodiumtrideceth-2 sulfate and cocamidopropyl betaine, citric acid and diproplylene glycol surfactant system as a function of dilution.

Structural alterations of branched versus linear mixed-surfactant micellar systems with the addition of a complex perfume mixture and dipropylene glycol as cosolvent

“…This observation implies that the PRMs (irrespective of their individual log P values) are preferentially located near the micelle core. This finding is very similar to our recent results for a 3 PRM system, 7 but the implication here is more significant, as the increased complexity in the system with 12 PRMs did not alter the perfume localization tendency. Furthermore, this finding differs from the behavior reported for individual PRMs in earlier studies.…”

“…When the 3 PRM accord and the present 12 PRM accord were added to a concentrated ST2S/CAPB system, self-assembly began with the formation of spherical structures that enlarged and eventually formed oblate ellipsoids in both cases. 7,31 Although the oil composition influences the extent to which a microemulsion can be diluted and the range of compositions which form microemulsions, 31 the differences in size and geometry between the present work and our past work could be caused by a few key differences—namely, the total surfactant concentration (7.5 wt% versus 20–32.5 wt%, respectively), and the ratio of perfume : surfactant : DPG, or both.…”

“…Nevertheless, these changes provided useful information about the preferential distribution of perfumes in the micelles. 7 In the SLE3S/CAPB system, protons ‘1’, ‘2’, and ‘3’ exhibited shielding effects upon perfume addition, indicating the localization of the perfume molecules near these surfactant protons. Similar effects were observed in the ST2S/CAPB system, but the shielding effect was more prominent for hydrophobic protons ‘1’ and ‘2’ than the more hydrophilic proton ‘3’.…”

“…As the fragrance is generated based on a complex PRM mixture, the relationship of the fragrance with the overall formulation is not straightforward. 3 Our previous work with a 3 PRM accord in a mixed-surfactant system with a cosolvent 7 revealed that surfactant, cosolvent, and oil combinations were not conducive to the formation of single-phase microemulsions. NMR analysis showed that the 3 PRMs were preferentially localized within the micelle core, regardless of their lipophilicities, indicating that perfume–perfume interactions strongly influence the location of a PRM within a surfactant self-assembly.…”

“…These surfactant systems were chosen as representative of the mixed-surfactant systems commonly used in personal care products for mildness. Moreover, these systems allowed us to expand upon our previous work 7 by investigating the influence of surfactant structure (branched (ST2S) versus linear (SLE3S)) on perfume localization. Furthermore, we determined the concentration of each PRM in the headspace of each mixed-surfactant system.…”