Surfactant adsorption and surface micellization

Gu, Tingyue; Zhu, Bu-Yao; Rupprecht, H.

doi:10.1007/bfb0114420

Cited by 57 publications

(35 citation statements)

References 25 publications

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“…It can be determined with different methods, but for our calculations the Gu and Zhu adsorption isotherm equation [13][14][15] as well as the Langmuir equation modified by de Boer [1,16] were chosen.…”

Section: Gibbs Standard Free Energy Of Ethanol Adsorption At the Solumentioning

confidence: 99%

“…The Gu and Zhu adsorption isotherm equation [13][14][15] was developed for the hydrophilic high-energy solids, but it turned out that it can be also useful for the investigation of adsorption process of ethanol at the solution-air interface. It has the following form: (k 1 and k 2 are the equilibrium constants of the surface monolayer and aggregate formation, respectively, n is the aggregation number of ethanol surface aggregates, 2 C is the molar concentration of ethanol and ∞ Γ 2 is the maximal surface excess concentration of ethanol).…”

Section: Gibbs Standard Free Energy Of Ethanol Adsorption At the Solumentioning

confidence: 99%

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Ethanol behaviour at the solution-air interface in the presence of Triton X-100 and cetyltrimethylammonium bromide mixture

Bielawska

Zdziennicka

2015

Annales UMCS, Chemia

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On the basis of the surface tension ( LV γ ) data of the aqueous solutions of p-(1,1,3,3-tetramethylbutyl)phenoxypoly(ethylene glycol) (Triton X-100 or TX-100) and cetyltrimethylammonium bromide (CTAB) mixture with ethanol published in our previous paper, the process of ethanol adsorption was investigated. For that reason, the values of Gibbs surface excess concentration of ethanol at the solution-air interface and Gibbs standard free energy of its adsorption at that interface were calculated and compared with those determined for the aqueous solutions of ethanol. The surface excess concentration of ethanol at the solution-air interface was calculated with two different methods. The standard free energy of alcohol adsorption was determined from both the Gu and Zhu and Langmuir equations.

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Section: Gibbs Standard Free Energy Of Ethanol Adsorption At the Solumentioning

confidence: 99%

Section: Gibbs Standard Free Energy Of Ethanol Adsorption At the Solumentioning

confidence: 99%

Ethanol behaviour at the solution-air interface in the presence of Triton X-100 and cetyltrimethylammonium bromide mixture

Bielawska

Zdziennicka

2015

Annales UMCS, Chemia

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“…5 The area occupied by one emulsifier molecule, A E [m 2 /(mol emulsifier)], is affected by the emulsifier used, temperature, electrolyte concentration, particle size, and nature of the polymer surface. 6 According to Gu et al, 7,8 surfactant adsorption differs for low and high surface concentrations of emulsifier. At low surface concentrations, the emulsifier is adsorbed through emulsifier particle surface interactions.…”

Section: Adsorption Of Emulsifier On Latex Particle Surfacesmentioning

confidence: 99%

“…9 At higher surface concentrations, hydrophobic interactions of the adsorbed surfactant molecules come into play. 8 The emulsifier molecules adsorb cooperatively, 9 favoring so-called surface micellization. 7 The adsorption isotherm of emulsifier on the surface of latex particles can take various forms, including Langmuir (L type), S-shaped (S type), and LS type.…”

Section: Adsorption Of Emulsifier On Latex Particle Surfacesmentioning

confidence: 99%

Colloidal stability of high-solids polystyrene and polyvinyl acetate latices

Kemmere

Meuldijk

Drinkenburg

et al. 1999

J. Appl. Polym. Sci.

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Commercial emulsion polymerization processes are often done with highsolids recipes (e.g., about 50 wt % monomer), resulting in relatively viscous, pseudoplastic reaction mixtures. The change in rheological behavior during high-solids emulsion polymerization complicates the operation in terms of imperfect mixing, increasing heat transfer resistance and reactor fouling. In this article, we report the influence of solids content on the colloidal stability of polystyrene (PS) and polyvinyl acetate (PVAc) latex systems. For the systems investigated, solids content up to 50 wt % had no influence on the colloidal stability of the latex. The influence of recipe on colloidal stability is more pronounced than the influence of operating conditions. Brownian coagulation dominates over shear coagulation for both low-and high-solids systems, although in some cases the operating conditions appear to have some effect on the course and outcome of high-solids emulsion polymerization.

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“…The next few decades witnessed the development of numerous adsorption models (based on a variety of assumptions) to describe the adsorption thermodynamics of different surfactant systems, among which were the Helfand-Frisch-Lebowitz (HFL) equation for freely moving hard discs on a fluid surface (Helfand et al, 1961), the Lucassen-Reynders thermodynamic approach (LucassenReynders, 1994(LucassenReynders, , 1966, and the Gu-Zhu isotherm for non-Langmuir adsorption undergoing surface aggregation (Gu et al, 1992), to just name a few. .…”

Section: Models For Nonionic Surfactantsmentioning

confidence: 99%

Molecular insights of adsorption and structure of surfactants and inorganic ions at fluid – liquid interfaces

Shahir¹

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Traditional approaches to studying fluid -liquid interfaces include the macroscopic measuring of interfacial properties such as surface tension and matching the collected data against adsorption models. This method is capable of producing valuable data about the thermodynamics of adsorption and has been widely used by the community to extract information about the adsorption of thousands of different surface-active molecules. Nonetheless, this methodology cannot produce any molecular-level information about the microscopic structure of adsorption layers and interfaces.As a result, the molecular origins of many interfacial phenomena remained unknown until the advent of surface-sensitive techniques such as computer simulation and non-linear spectroscopy.The new insights provided by these methods have challenged the traditional views about the origins of some interfacial phenomena and promise modification of classical theories which were developed to explain these phenomena.In general, this thesis aims to study the interfacial structure and adsorption of ionic surfactants, some surface-active alcohols as model nonionic surfactants including, n-pentanol, methyl isobutyl carbinol (MIBC) and n-hexanol and inorganic salts including LiCl, NaCl and CsCl at both microscopic and macroscopic levels. The employed methodology involves a combination of traditional adsorption modelling with some macroscopic measurements and sum frequency generation (SFG) spectroscopy, which is capable of distinguishing between bulk and interfacial molecules. Using SFG spectroscopy, the interfacial structure of adsorption layers and the composition of interfaces were investigated in detail and independently of the bulk solution.Specifically, the surface saturation of solutions of MIBC was identified directly using SFG spectroscopy and was then compared to equilibrium surface tension data to find that surface tension surprisingly continued to decrease even after full surface saturation. This is in contradiction to the traditional view that all surfactants adsorb at the outermost adsorption monolayer. Because of the limited surface area of the topmost adsorption monolayer, its full saturation is considered as the end of the adsorption process. This view is based on the notion of Gibbs dividing plane, which is usually taken as being equal to the physical adsorption monolayer in a surfactant solution. The postsaturation surface tension decrease, therefore, cannot be explained by the Gibbs convention. A different adsorption geometry, which considers the under-monolayer adsorption of alcohols, was proposed based on the Guggenheim extended interface model. In Chapter 5, a recent controversy about the applicability of the famous Gibbs adsorption isotherm to the analysis of surface tension data was addressed with regards to the new concept of under-monolayer adsorption. The results showed that the linearity of a surface tension plot is not necessarily indicative of a fully saturated ii surface. The same adsorption geometry was also proposed for t...

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Surfactant adsorption and surface micellization

Cited by 57 publications

References 25 publications

Ethanol behaviour at the solution-air interface in the presence of Triton X-100 and cetyltrimethylammonium bromide mixture

Ethanol behaviour at the solution-air interface in the presence of Triton X-100 and cetyltrimethylammonium bromide mixture

Colloidal stability of high-solids polystyrene and polyvinyl acetate latices

Molecular insights of adsorption and structure of surfactants and inorganic ions at fluid – liquid interfaces

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