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

Wieczorek, Stefan A.

doi:10.1006/jcht.1999.0621

Cited by 4 publications

(1 citation statement)

References 17 publications

(51 reference statements)

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“…The Table 2. Aggregation Numbers from the Literature compound literature C6E3 30,32,33,59 24−57 C6E4 33 28 C6E5 32,33,38,59,60 21−55 C8E4 32,61−63 23−147 C8E5 59,64−68 17−90 C8E6 43,69,70 30−41 C10E5 59,71 17−172 C10E6 67,69−71 66−105 C10E8 44,50,67,72 46−70 C12E5 1,66,73,74 112−4460 C12E6 1,43,65,70,73,75−83 100−555 C12E8 1,57,61,65,74,83−88 39−159 intensity−intensity time correlation function of the detected signal, called a correlogram, is computed, which exhibits a characteristic decay with increasing lag time. (See left graph in Figure 1.)…”

Section: Methodsmentioning

confidence: 99%

Challenge to Reconcile Experimental Micellar Properties of the CnEm Nonionic Surfactant Family

et al. 2019

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We wished to compile a data set of results from the experimental literature to support the development and validation of accurate computational models (force fields) for an important class of micelle-forming nonionic surfactant compounds, the poly(ethylene oxide) alkyl ethers, usually denoted C n E m . However, careful examination of the experimental literature exposed a striking degree of variation in values reported for critical micelle concentrations (cmc) and mean aggregation numbers (N agg ). This variation was so large that it masked important trends known to exist within this family of molecules, thereby rendering most of the literature data to be of limited utility for force field development. In this work, we describe some reasons for the wide variability in the experimental literature, and we present a set of cmc and aggregation number data for 12 C n E m compounds that we feel is appropriate to use for the construction of and validation of computational models. The cmc values we selected are from the existing experimental literature and represent a carefully chosen and consistent subset that conveys important trends seen by many of the experimental studies. However, for a corresponding and consistent set of weight-averaged aggregation numbers, we needed to perform new dynamic light scattering (DLS) experiments. The results of these experiments were carefully analyzed to obtain not just mean aggregation numbers but also the underlying micelle size distribution functions. Several trends observed in the cmc and N agg observables are highlighted and serve as challenges for developers of force field and simulation methodology. The analysis of the DLS experiments accounts for the fact that a broad distribution of micelle sizes exists for many of these compounds and that one must be careful to use the appropriate weighted averages (e.g., mass-weighted vs number-weighted averages) in comparing results from different types of experiments and in comparing results from experiments with those from simulations.

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