Effects of Temperature, Salt, and Deuterium Oxide on the Self-Aggregation of Alkylglycosides in Dilute Solution. 1. n-Nonyl-β-d-glucoside

Abstract

The influence of salt, temperature, and deuterium oxide on the self-aggregation of n-nonyl-beta-D-glucoside (beta-C9G1) in dilute solution has been investigated by static and dynamic light scattering, neutron scattering, and tensiometry. Scattering data show that the micelles can be described as relatively stiff, elongated structures with a circular cross section. With a decrease of temperature, the micelles grow in one dimension, which makes it surprising that the critical micelle concentration (cmc) shows a concomitant increase. On the other hand, substitution of D2O for H2O causes a large increase in micelle size at low temperatures, without any appreciable effect on cmc. With increasing temperature, the deuterium effect on the micelle size diminishes. The effects of salt on the micelle size and cmc were found to follow the Hofmeister series. Thus, at constant salt concentration, the micelle size decreased according to the sequence SO4(2-) > Cl- > Br- > NO3- > I- > SCN-, whereas the effect on cmc displays the opposite trend. Here, I- and SCN are salting-in anions. Similarly, the effects of cations decrease with increasing polarizability in the sequence Li+ > Na+ > K+ > Cs+. At high ionic strength, the systems separate into two micellar phases. The results imply that the size of beta-C9G1 micelles is extremely sensitive to changes in the headgroup size. More specifically, temperature and salt effects on effective headgroup size, including intermolecular interactions and water ofhydration, are suggested to be more decisive for the micelle morphology than the corresponding effects on unimer solubility.

Effect of NaCl on the Self-Aggregation of n-Octyl β-d-Thioglucopyranoside in Aqueous Medium

“…This loss of solvate molecules is likely to reduce the effective headgroup size. 51 A volume decrease of the polar part of the surfactant molecule will lead to a decreased stability of a spherical, but a stabilization of a planar, arrangement of the surfactant molecule. 52 A reduction of curvature, i.e., a tendency toward a more planar arrangement will, of course, favor association and the subsequent growth of micelles.…”

Synthesis, preliminary characterization, and application of novel surfactants from highly branched xyloglucan oligosaccharides

“…CMC values obtained from the break-points of the surface tension isotherms (estimated as the intersection of lines fitted to the descending and flat portions of the curves) were in good agreement with those obtained by the dye-inclusion method (Table I). The minimum surface tension, γ min , was in the range 47-53 mN/m, which is remarkably high compared to many sugar-based surfactants (Augé and LubinGermain, 2000;Ericsson et al, 2004;Ferrer et al, 2002;Garofalakis et al, 2000;Kjellin et al, 2001;Persson et al, 2000;Söderberg et al, 1995;Waltermo et al, 1996). An anomalously high γ min value can result when the Krafft point of the surfactant is passed at high concentration, which effectively results in the precipitation of the surfactant from solution.…”

“…In particular, recent fundamental studies have sought to elucidate the behavior of the simple alkylglucosides in the context of other well-characterized nonionic surfactants, namely, those based on poly(ethene oxide) head groups (Ericsson et al, 2004). Interest in surfactants derived from sugars other than glucose has been extended to include other monosaccharides, as well as linear di-, tri-, and tetrasaccharides (Costes et al, 1995;Ferrer et al, 2002;Garofalakis et al, 2000;Kjellin et al, 2001;Plou et al, 2002;Söderberg et al, 1995).…”

Mixed micelles of series of monomeric and dimeric cationic, zwitterionic, and unequal twin-tail cationic surfactants with sugar surfactants: A fluorescence study

“…Recently, some interesting research works have appeared in the literature [1][2][3][4][5][6][7] regarding the mixed micelle behavior of nonionic sugar surfactants. A sugar surfactant is widely used in various fields of biochemistry, which includes biomembranes and bilayer assemblies [8,9].…”