An HLD framework for cationic ammonium surfactants

Schirone, Davide; Tartaro, Giuseppe; Gentile, Luigi; Palazzo, Gerardo

doi:10.1016/j.jciso.2021.100033

Cited by 11 publications

(10 citation statements)

References 69 publications

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“…However, it is much lower, around 0.00006 mol/L, for another water-soluble specie like dodecyl pentaethoxylate, because of the importance of head structure on aggregation. Its decimal logarithm decreases almost linearly with the number of carbon atoms in an alkyl tail and also increases linearly as the ethylene oxide number of an ethoxylated nonionic increases. , The CMC is also very sensitive to external effects of solubilization in solution, like the salinity and hardness of the aqueous phase and the temperature.…”

Section: Basic Phase Behavior and Occurrences In A Sow System At Equi...mentioning

confidence: 99%

“…Its decimal logarithm decreases almost linearly with the number of carbon atoms in an alkyl tail and also increases linearly as the ethylene oxide number of an ethoxylated nonionic increases. 6,29 The CMC is also very sensitive to external effects of solubilization in solution, like the salinity and hardness of the aqueous phase and the temperature.…”

Section: ■ Introductionmentioning

confidence: 99%

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Review on Some Confusion Produced by the Bicontinuous Microemulsion Terminology and Its Domains Microcurvature: A Simple Spatiotemporal Model at Optimum Formulation of Surfactant-Oil-Water Systems

et al. 2023

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Fundamental studies have improved understanding of molecular-level properties and behavior in surfactant-oil-water (SOW) systems at equilibrium and under nonequilibrium conditions. However, confusion persists regarding the terms “microemulsion” and “curvature” in these systems. Microemulsion refers to a single-phase system that does not contain distinct oil or water droplets but at least four different structures with globular domains of nanometer size and sometimes arbitrary shape. The significance of “curvature” in such systems is unclear. At high surfactant concentrations (typically 30 wt % or more), a single phase zone has been identified in which complex molecular arrangements may result in light scattering. As surfactant concentration decreases, the single phase is referred to as a bicontinuous microemulsion, known as the middle phase in a Winsor III triphasic system. Its structure has been described as involving simple or multiple surfactant films surrounding more or less elongated excess oil and water phase globules. In cases where the system separates into two or three phases, known as Winsor I or II systems, one of the phases, containing most of the surfactant, is also confusedly referred to as the microemulsion. In this surfactant-rich phase, the only curved objects are micellar size structures that are soluble in the system and have no real interface but rather exchange surfactant molecules with the external liquid phase at an ultrafast pace. The use of the term “curvature” in the context of these complex microemulsion systems is confusing, particularly when applied to merged nanometer-size globular or percolating domains. In this work, we discuss the terms “microemulsion” and “curvature”, and the most simple four-dimensional spatiotemporal model is proposed concerning SOW equilibrated systems near the optimum formulation. This model explains the motion of surfactant molecules due to Brownian movement, which is a quick and arbitrary thermal fluctuation, and limited to a short distance. The resulting observation and behavior will be an average in time and in space, leading to a permanent change in the local microcurvature of the aggregate, thus changing the average from micelle-like to inverse micelle-like order over an extremely short time. The term “microcurvature” is used to explain the small variations of globule size and indicates a close-to-zero mean curvature of the surfactant-containing film surface shape.

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Section: Basic Phase Behavior and Occurrences In A Sow System At Equi...mentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

Review on Some Confusion Produced by the Bicontinuous Microemulsion Terminology and Its Domains Microcurvature: A Simple Spatiotemporal Model at Optimum Formulation of Surfactant-Oil-Water Systems

et al. 2023

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“…The abbreviation

ΔT describes the influence of temperature variations regarding the reference temperature (25 °C), where

is slightly positive for ionic surfactants (0.01–0.02 for cationic surfactants) and is negative for ethoxylated surfactants [ 187 ]; ΔT is the temperature difference between the actual and reference temperatures [ 188 ]. In order to obtain the

value, a graphical relationship between optimal salinity and temperature for a particular surfactant and oil can be used, and the arithmetic slope represents the

.…”

Section: Bitumen Emulsion Formulation Toolsmentioning

confidence: 99%

Current Research and Challenges in Bitumen Emulsion Manufacturing and Its Properties

Al-Mohammedawi

Mollenhauer

2022

Materials

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The global increase of road infrastructure and its impact on the environment requires serious attention to develop sustainable and environmentally friendly road materials. One group of those materials is produced by using bitumen emulsion. However, there are still scientific and technical obstacles standing against its regular application. The bitumen emulsion formulation process and compositional optimization are subjected to a high number of degrees of freedom. Consequently, obtaining the desired product is mostly based on a series of random and tedious trials because of the enormous number of tests that are carried out to meet the required properties, such as emulsion stability, viscosity, droplet size (and distribution), and bitumen emulsion chemistry. Several pre-established formulation procedures have been presented in the literature. Some of them have technical limitations to be utilized for practical industrial application, whereas others are still not understood enough to be applied in bitumen emulsion formulation. Therefore, discussing some important issues in this field could be useful to offer a practical guide for bitumen emulsion manufacturers when trying to formulate a well-defined bitumen emulsion to best fit its use in pavement infrastructure rather than to simply to meet standard specifications. This review paper aims to enable the ultimate potential of bitumen emulsion by further reviewing the research progress of bitumen emulsion manufacturing and discussing the literature available up to now on this topic, in the realm of bitumen emulsion manufacturing and emulsion chemistry.

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“…This observation is consistent with the bi reported for DPCl is the lowest among the surfactants reported in this work. The group of Palazzo has recently introduced novel methods to measure Cc using mixtures of test cationic surfactants with a reference surfactant, didodecyl dimethyl ammonium bromide (DDAB) (Schirone et al, 2022(Schirone et al, , 2021. Using mixtures of DDAB and DTAB (dodecyl trimethyl ammonium bromide, a molecule similar to DPCl), Schirone et al determined that the Cc of DTAB was -10, with an EACN prefactor "k" of ~ 0.7.…”

Section: Experimental Determination Of Ccbi and CC For Cationic Surfa...mentioning

confidence: 99%

“…and Schirone et al(Schirone et al, 2021); for C16DPODS from Shiau et al(Shiau et al, 2013) inspired this work, can the characteristic curvature (Cc) definition be used to measure Cc values? The hypothesis was that if the correlation equation for HLD did express the chemical potential difference between the surfactant in oil and the surfactant in water, then the normalized net curvature interpretation was expected to hold (HLD ~ -L•Hn).…”

mentioning

confidence: 95%

The characteristic curvature (Cc) definition and its use in assessing Cc for single ionic surfactants

Leng

Acosta

2022

Preprint

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The Hydrophilic-Lipophilic-Difference (HLD) is a set of empirical equations that correlate the formulation conditions at phase inversion (HLD=0). Based on partition studies for nonionic surfactants, the HLD can be interpreted as a normalized chemical potential difference between the surfactant dissolved in water and oil. The Net-Average Curvature (NAC) model extrapolates this interpretation into a curvature form that has been used to fit and predict the phase behavior of surfactant-oil-water (SOW) systems. The curvature interpretation of HLD led to the renaming of the HLD surfactant parameter, sigma (σ), as the characteristic curvature (Cc). This work addresses two concerns around this interpretation; first, for ionic surfactants, an HLD≠0 value for one surfactant might not mean the same for another (breaking the chemical potential interpretation), and second, the Cc interpretation has not been demonstrated. To this end, the net curvature (Hn) of six anionic and two cationic surfactants was evaluated (individually) from solubilization data at the characteristic condition of 25°C, no added cosolvent, in the presence of an oil mixture with equivalent alkane carbon number (EACN) of zero, and as a function of salinity. These studies showed that, indeed, the original HLD equation for ionic surfactant could not be interpreted as chemical potential or curvature because a salinity prefactor "bi" was missing. The revised equation, HLDbi = bi∙ln(S)-kbi∙EACN+Ccbi -aTbi∙(T-25°C), could now be interpreted as a curvature expression, and it was demonstrated that Cc could be obtained from curvature at characteristic conditions, only that the proper expression is Cc = Ccbi/bi.

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An HLD framework for cationic ammonium surfactants

Cited by 11 publications

References 69 publications

Review on Some Confusion Produced by the Bicontinuous Microemulsion Terminology and Its Domains Microcurvature: A Simple Spatiotemporal Model at Optimum Formulation of Surfactant-Oil-Water Systems

Review on Some Confusion Produced by the Bicontinuous Microemulsion Terminology and Its Domains Microcurvature: A Simple Spatiotemporal Model at Optimum Formulation of Surfactant-Oil-Water Systems

Current Research and Challenges in Bitumen Emulsion Manufacturing and Its Properties

The characteristic curvature (Cc) definition and its use in assessing Cc for single ionic surfactants

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