The Physicochemical Behavior of Phytosterol Ethoxylates

Phase Behavior of Phytosterol Ethoxylates in an Imidazolium-Type Room-Temperature Ionic Liquid

“…These trends are similar to those observed in the BPS-n water systems 15 , and hence, the data suggest that the overall phase behavior in the BPS-n BmimPF 6 systems is largely similar to that in the BPS-n water systems. However, notable differences in the phase states are observed in each of the two liquid systems.…”

“…It should be recalled here, that in the mixed system comprising BPS-n in BmimPF 6 , the oxyethylene unit of BPS-n acts as a solvophilic group and the phytosterol unit acts as a solvophobic group 4 . This situation is similar to the aqueous BPS-n system 15 , and hence, it is possible to understand the observed phase change using the concept of critical packing parameter CPP 16 ; the increased surfactant concentration results in an increased CPP, and hence, lesser-curved molecular assemblies tend to be formed, as observed in Fig. 2.…”

“…For example, the H 1 phase is observed in the BPS-10 water and BPS-30 water systems 15 , whereas this phase does not appear in the corresponding BmimPF 6 systems. Similarly, the L 2 phase is observed in the BPS-10, BPS-20, and BPS-30 aqueous systems but the observed region is limited at high temperatures and at high surfactant concentrations 15 , whereas the L 2 phase is not identifi ed in the corresponding BmimPF 6 systems within the investigated temperature-concentration range. Second, the temperature-concentration region in which a phase that is common to both systems is observed is somewhat different for the BmimPF 6 versus the aqueous system.…”

“…This is exemplified by the experimental observation that at the fixed temperature of 25 , the I 1 -L 1 phase transition occurs at a BPS-20 concentration of 34-35 wt in the BPS-20 BmimPF 6 system, whereas this transition occurs at a BPS-20 concentration of ca. 26 wt in the BPS-20 water system 15 . The occurrence of the phase transition at higher BPS-20 concentrations in the BmimPF 6 system relative to the water system presumably results from the greater solvophilic nature of BPS-n with BmimPF 6 than with water, as was similarly suggested for the polyoxyethylene alkyl ether surfactants EAN/water systems 8 .…”

Phase behavior and surface tensions of amphiphilic fluorinated random copolymer aqueous solutions

“…3. The time taken to attain constant surface tension during measurement was very long, often 2-3 h. The very long time needed to reach the equilibrium surface tension is most likely related to the conformational change at the air-water interface [23]. The surface tension values were cross-examined by spinning-drop technique at 0.1 and 1 wt.% copolymer concentration.…”