Small angle neutron scattering of D2O–Brij 35 and D2O–alcohol–Brij 35 solutions and their modelling using the Percus–Yevick integral equation

Abstract

Small angle neutron scattering of direct micelles in binary and ternary surfactantÈalcoholÈ surfactantÈD 2 O systems has been measured. The nonionic surfactant was poly(oxyethylene-23) lauryl ether D 2 O (C 12 E 23, commercial name : Brij 35) which was used at concentrations far beyond its critical micellar concentration : between 0.1 and 15 mass% (about 1.0 ] 10~3È1.5 ] 10~1 mol l~1). The alcohols were butan-1-ol, pentan-1-ol, hexan-1-ol, and heptan-1-ol at concentrations of about 0.25 mol l~1. The spectra could quantitatively be modelled by the PercusÈYevick integral equation method in combination with a core/shell model yielding detailed information about the size, the (ellipsoidal) shape, the aggregation number, the internal structure and the distribution of the micelles. The ternary systems were modelled with an additional parameter, the partition of the alcohol between the outer aqueous bulk and the inner micellar pseudo-phase. In the case of the pentanol system the partition coefficient inferred from NMR self-di †usion measurements was used to describe the scattering result.

Biooxidation of n‐hexanol by alcohol oxidase and catalase in biphasic and micellar systems without solvent

“…Both the initial velocity of the bioconversion to propanal and the yield after 24 h turned out to be independent of the presence of Brij 35, even at surfactant concentrations as high as 20 mass%. A second test showed that results similar to those given in Figure 2 were (Preu et al, 1999). obtained in the microemulsion systems. Furthermore, a linear increase in both the initial activity and in the conversion yield after 24 h as a function of enzyme unities was observed as in the case of biphasic systems, suggesting that, in both cases, the enzymatic activity was controlled by kinetics and not by diffusion.…”

“…In an earlier study, the molecular architecture of these systems was studied in some detail using neutron scattering and statistical mechanics, and by using another type of enzyme (Preu et al, 1999;Schirmer et al, 2002). It turned out that the solutions with compositions similar to those used in the present study (up to 12 mass% of hexanol, up to 20 mass% of surfactant, and the rest being water or an aqueous solution; see Fig.…”

“…The phase diagram of water/hexanol/Brij 35 has already been investigated along with the accompanying micellar systems and microemulsions (Preu et al, 1999;Schirmer et al, 2002).…”

Glucose-induced sphere to ellipsoid transition of polyoxyethylene–polyoxypropylene block copolymer micelles in aqueous solutions

“…by the nonionic surfactants polyoxyethylene(5)-dodecylether [1], polyoxyethylene(6)-hexadecylether [2,3], and sucrose laurate [4] change shape from sphere to rod with increasing temperature. The micelle shape can also be affected by varying the solvent properties [5][6][7][8][9][10][11][12][13]. The synergistic effects of solvent quality and temperature can be very important in modulating the self-assembly of nonionic amphiphiles in aqueous solutions.…”

Effect of perfluorinated surfactant as additive of background electrolyte for capillary electrophoresis of inorganic cations

“…The fact was expected to cause the diffusion of sample zone in the capillary, because the velocity of divalent cations penetrating to the PFOSA micelle was slower than that of the BGE [31]. The BGE containing 30 mM Brij 35 as a nonionic surfactant and those containing 30 mM C12N3S and 20 mM DPC as zwitterionic surfactant, which are well above the critical micellar concentration (CMC) [32][33][34], were attempted for cation separations. As can be seen in Fig.…”