Variations in the micelle size of non-ionic detergents

Abstract

A light-scattering study has been made of the effect of concentration and temperature on the micellar size in a series of homogeneous non-ionic detergents in aqueous solution. It has been found that above the critical micelle concentration, as determined by surface tension measurements, an increase in micellar size takes place until a critical concentration is reached. Above this value, constant micellar molecular weights are observed for a finite concentration increase.All the compounds examined show an approximately exponential dependence of micellar molecular weight on temperature. The logarithmic temperature coefficients are similar for the higher homologues examined.

Microcalorimetric Study of Some Short-Chain Nonionic Surfactants

“…Nevertheless, although a lot of information has been pubAll experiments were performed at 25.00 { 0.01ЊC. In the lished on compounds with hydrophobic chains having ten case of C 8 E 5 a set of dilutions was performed starting from or more methylene groups (1)(2)(3), there are relatively few the pure surfactant. The C 8 E 5 is slightly hygroscopic, and studies on short-chain surfactants whose aggregation mechathe original product contains a small amount of water (about nism is only weakly cooperative.…”

Thermodynamics of aqueous mixtures of polyoxyethene glycol monoethers V. Excess molar volumes of (n-decyl hexaoxyethene glycol monoether + water) in the vicinity of the critical micelle composition

“…aggregation number N were held fixed during the fit of V E m in the vicinity of the c.m.c. On the basis of light scattering measurements (4) we have used N = (73, 260, and 640) at T = (298.144, 308.141, and 318.143) K, respectively. For the experimental results of V E m over the whole range of composition (Run III at T = 298.144 K) two different ranges of x were fitted.…”

“…(8) The micelles are formed only in two of them, i.e. in the aqueous solution of C 6 H 13 O(CH 2 CH 2 O) 3 H (6) 4 H. (8) These two systems exhibit a reasonably high value for the critical micelle composition (c.m.c.) which is easily accessible to experimental investigation.…”

“…with a very flat minimum at T c = 332.15 K. The authors (1,2) found a substantial area (0.028 < x < 0.073) of the hexagonal phase in which lyotropic liquid crystals in equilibrium with the micellar phase are formed. Earlier measurements of vapour pressures, (1) enthalpies of mixing, (1) surface tension, (3) and light scattering (4) for the system studied are available in the literature.…”

Intermolecular association and molecular weight of aggregates of a monodisperse homohexapeptide, Nps‐[Glu(OBzl)]6‐NHEt, in solution

“…If the content of 0-form is represented by f , the molar extinction coefficient, c-,, at wave number G, is given by (17) where c-,P and cf are the molar extinction coefficients of 0-and a-forms, respectively. Choosing two peak positions of the amide I bands at 1630 and 1670 cm-l as ij, the content of 0-form can be obtained by…”