Effects of Salts Containing Mono-, Di-, and Trivalent Ions on Electrical and Rheological Properties of Oil-Water Interface in Presence of Cationic Surfactant: Importance in the Stability of Oil-in-Water Emulsions

Ghosh, Pallab; Banik, Meneka

doi:10.1080/01932691.2013.791990

Cited by 12 publications

(23 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The observation of an increase in AOT surface concentration in this study is consistent with previous studies investigating the adsorption of ionic surfactants to both the air–water and oil–water interfaces which found that the presence of salt will increase the interfacial surfactant concentration. − For ionic surfactants, such as AOT, the increased surface population of surfactants can be linked to a reduction in the Debye screening length. As salt is added to the solution, increases in ionic strength result in decreases in the Debye screening length .…”

Section: Resultssupporting

confidence: 91%

“…This study takes advantage of the screening nature of aqueous solution salts on the field generated by charged surfactants at the nanoemulsion surface. For ionic surfactants, repulsive interactions between the nearest-neighbor surfactant head groups can be screened by changing the identity and concentration of ions in solution. , The addition of mono- and multivalent salts to the aqueous phase has been shown to increase the density of ionic surfactants at planar air–water and oil–water interfaces. − Changes in the surfactant density at nanoemulsion surfaces have also been observed to result from changes to the surfactant counterion, as well as the addition of salt to the continuous aqueous phase. ,,, The common finding across all of these studies is that the density of ionic surfactants at both the planar and nanoemulsion surfaces is affected by screening repulsive interactions between ionic head groups and that this can be controlled by altering the ionic properties of the surfactant counterion and the ionic strength of the aqueous solution.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Effects of Salt-Induced Charge Screening on AOT Adsorption to the Planar and Nanoemulsion Oil–Water Interfaces

et al. 2021

View full text Add to dashboard Cite

Nanoemulsions, nanosized droplets of oil, are easily stabilized by interfacial electric fields from the adsorption of ionic surfactants. While mean-field theories can be used to describe the impact of these interfacial fields on droplet stability, the influence of these fields on the adsorption properties of ionic surfactants is not well-understood. In this work, we study the adsorption of the surfactant sodium dioctyl sulfosuccinate (AOT) at the nanoemulsion and planar oil–water interfaces and investigate how salt-induced charge-screening affects AOT adsorption. In the absence of salt, vibrational sum-frequency scattering spectroscopy measurements reveal the ΔG ads and the maximum surface density is the same for AOT at the hexadecane nanoemulsion surface as at the planar hexadecane–H2O interface. Upon the addition of NaCl, an increase in AOT surface density is detected at both interfaces, indicating that repulsive electrostatic interactions between AOT monomers are the dominant force limiting surfactant adsorption at both interfaces. The bulky alkyl chains of AOT molecules cause our observations in this study to differ from those found in previous studies investigating the adsorption of linear-chain ionic surfactants to the nanoemulsion surface. These results provide necessary information for understanding factors limiting the adsorption of ionic surfactants to nanodroplet surfaces and highlight the need for further studies into the adsorption properties of more complex macromolecules at nanoemulsion surfaces.

show abstract

Section: Resultssupporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Effects of Salt-Induced Charge Screening on AOT Adsorption to the Planar and Nanoemulsion Oil–Water Interfaces

et al. 2021

View full text Add to dashboard Cite

show abstract

“…Figure 4B shows the 0-day ζ potential of the emulsion droplets studied in the previous section. Increasing the NaCl concentration decreased γ eq , 28,46,47 and the rate of change in γ eq decreases. A plateau in γ eq was achieved at approximately 0.5 M NaCl as this γ eq was within the measurement precision (0.3 mN/m) of the minimum γ eq measured (1.0 M NaCl).…”

Section: Resultsmentioning

confidence: 91%

“…If emulsion stability is only measured during this initial period, then one may conclude that the overall emulsion is unstable. 25,27,28 However, the stability of the droplets that did not coalesce and phase separate likely increases as the S/O increases.…”

Section: Resultsmentioning

confidence: 99%

Impact of Saltwater Environments on the Coalescence of Oil-in-Water Emulsions Stabilized by an Anionic Surfactant

et al. 2021

View full text Add to dashboard Cite

The impact of salts on the stability of oil-in-water emulsions to coalescence was studied to aid in minimizing the impact of emulsified oils on natural water systems. Oil-in-water emulsions were fabricated from mineral oil, deionized water, and sodium lauryl ether sulfate. As salt (NaCl) concentrations increased from 0 to 1.25 M, an increase in emulsion stability to coalescence was observed over an aging period of 56 days. ζ potential and interfacial tension measurements showed that salt decreased the electrostatic repulsion of the anionic surfactant and allowed the surfactant to pack more densely at the oil−water interface. Dynamic interfacial tension measurements showed that surfactant adsorption rates increased with salt. As a result of faster adsorption kinetics, oscillating droplet tensiometry showed a decrease in the dilatational modulus when salt was present. An extended DLVO theory was used to calculate the interaction energy between droplets. These calculations agreed well with our experimental results indicating the importance of hydration forces at high salt concentrations and small droplet separation distances. The presence of salt allowed for close surfactant packing and faster surfactant adsorption kinetics, which prevented coalescence and created conditions favorable for the formation of a stable Newton black film.

show abstract

“…From application based objectives, studies reported on the emulsion stability governed by electrolyte addition in the mixture of phospholipids with varied nonionic surfactants, ABA poly(oxyethylene) (POE), poly(oxypropylene) (POP) block copolymers (poloxamers), where POE segments provided stability in the aqueous media by a repulsion effect and POP acted as the initiator of monomer formation. , Meanwhile, a recent study explored the non-Newtonian and shear thinning behavior of a cationic-nonionic surfactant (CPB-Span-40) with varied nonionic head groups on sodium carboxymethyl cellulose (NaCMC). These interactions were studied in bulk as well as at the air–water interface using solution theory insight providing applications as viscosity modifiers in food additives, as a thickener and binder in cosmetic products and in enhanced oil recovery …”

Section: Introductionmentioning

confidence: 99%

Effect of Electrolytes on Solution and Interfacial Behaviors of Double Chain Cationic–Nonionic Surfactant Mixtures for Hydrophobic Surface Wetting and Oil/Water Emulsion Stability Applications

Banerjee

Paria

2021

Langmuir

View full text Add to dashboard Cite

The solution behaviors of the binary mixture of double chain cationic surfactant didodecyldimethylammonium bromide (DDAB) with nonionic surfactants of varied head groups, EO-9 and EO-40, in the presence and absence of electrolytes were studied and found nonideal behavior. The different physicochemical properties such as Gibb’s surface excess (Γ), minimum area per molecule (A min), and interaction parameters at bulk (β M ) and interface (β σ ) were calculated. In the presence of nonionic surfactants, lowering of CMC, CVC, and surface tension at these two concentrations of DDAB were observed. The β M and β σ values indicate strong interaction between DDAB and EO-40 mixed system. Further, addition of electrolytes to the mixed systems show increased interaction and change of physicochemical properties because of the combination of electrical and salting out effects.

show abstract

Effects of Salts Containing Mono-, Di-, and Trivalent Ions on Electrical and Rheological Properties of Oil-Water Interface in Presence of Cationic Surfactant: Importance in the Stability of Oil-in-Water Emulsions

Cited by 12 publications

References 38 publications

Effects of Salt-Induced Charge Screening on AOT Adsorption to the Planar and Nanoemulsion Oil–Water Interfaces

Effects of Salt-Induced Charge Screening on AOT Adsorption to the Planar and Nanoemulsion Oil–Water Interfaces

Impact of Saltwater Environments on the Coalescence of Oil-in-Water Emulsions Stabilized by an Anionic Surfactant

Effect of Electrolytes on Solution and Interfacial Behaviors of Double Chain Cationic–Nonionic Surfactant Mixtures for Hydrophobic Surface Wetting and Oil/Water Emulsion Stability Applications

Contact Info

Product

Resources

About