Co-solvent Effect on Spontaneous Formation of Large Nanoscale Structures in Catanionic Mixtures in the Anionic-Rich Region

AbstractThe aggregation behavior was investigated in mixtures of sodium dodecyl sulfate (SDS) and cetyltrimethylammonium bromide (CTAB) (anionic-rich catanionic) solutions. The study was conducted in solutions of water–ethylene glycol (EG) by means of surface tension, conductometry, cyclic voltammetry, zeta potential measurements, transmission electron microscopy (TEM) and dynamic light scattering (DLS) techniques. The degree of counterion dissociation (α), critical micelle concentration, aggregation numbers, interfacial properties, interparticle interaction parameters, and morphology of aggregates were determined. Based on regular solution theory, the cosolvent effects between SDS and CTAB as surfactants were also analyzed for both mixed monolayers at mixed micelles (βM) and the air/liquid interface (βσ). It was shown that the formation of large aggregates occurred in the presence of an excess of anionic surfactant. A phase transition from cylindrical micelles to spherical micelles in the anionic-rich regime was observed with an increase in the EG volume fraction. The inter particle interactions were assessed in terms of cosolvent effects on the micellar surface charge density and the cylindrical-to-spherical morphology change. Zeta potential and size of the aggregates were determined using dynamic light scattering and confirmed the models suggested for the processes taking place in each system.

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Adsorption of Sodium Dodecyl Sulfate on Polystyrene Latex Particles Using Dynamic Light Scattering and Zeta Potential Measurements. [Erratum to document cited in CA118:234941]

Macromolecules ◽

10.1021/ma00110a053 ◽

1995 ◽

Vol 28 (6) ◽

pp. 2103-2103 ◽

Cited By ~ 2

Author(s):

Wyn Brown ◽

Jianxi Zhao

Keyword(s):

Light Scattering ◽

Sodium Dodecyl Sulfate ◽

Dynamic Light Scattering ◽

Zeta Potential ◽

Sodium Dodecyl ◽

Polystyrene Latex ◽

Latex Particles ◽

Dodecyl Sulfate ◽

Polystyrene Latex Particles

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Adsorption of sodium dodecyl sulfate on polystyrene latex particles using dynamic light scattering and zeta potential measurements

Macromolecules ◽

10.1021/ma00063a012 ◽

1993 ◽

Vol 26 (11) ◽

pp. 2711-2715 ◽

Cited By ~ 55

Author(s):

Wyn Brown ◽

Jianxi Zhao

Keyword(s):

Light Scattering ◽

Sodium Dodecyl Sulfate ◽

Dynamic Light Scattering ◽

Zeta Potential ◽

Sodium Dodecyl ◽

Polystyrene Latex ◽

Latex Particles ◽

Dodecyl Sulfate ◽

Polystyrene Latex Particles

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Electroacoustic Study of n-Hexadecane/Water Emulsions

Australian Journal of Chemistry ◽

10.1071/ch01148 ◽

2001 ◽

Vol 54 (8) ◽

pp. 503 ◽

Cited By ~ 8

Author(s):

Linggen Kong ◽

James K. Beattie ◽

Robert J. Hunter

Keyword(s):

Particle Size ◽

Zeta Potential ◽

Volume Fraction ◽

Sodium Dodecyl ◽

Surfactant Solution ◽

Minimum Size ◽

Water Mixture ◽

Concentrated Suspensions ◽

Minimum Concentration ◽

Median Diameter

n-Hexadecane-in-water emulsions were investigated by electroacoustics using a prototype of an AcoustoSizer-II apparatus. The emulsions were formed by passing the stirred oil/water mixture through a homogenizer in the presence of sodium dodecyl sulfate (SDS) at natural pH (6–7). With increasing oil-volume fraction, the particle size increased linearly after 5 and also after 20 passages through the homogenizer, suggesting that surface energy was determining particle size. For systems in which the surfactant concentration was limited, the particle size after 20 passages approached the value dictated by the SDS concentration. With ample surfactant present, the median diameter was a linear function of the inverse of the total energy input as measured by the number of passes. There was, however, a limit to the amount of size reduction that could be achieved in the homogenizer, and the minimum size was smaller at smaller volume fractions. Dilution of the emulsion with a surfactant solution of the same composition as the water phase had a negligible effect on the particle size and changed the zeta potential only slightly. This confirms results from previous work and validates the equations used to determine the particle size and zeta potential in concentrated suspensions. The minimum concentration of SDS that could prevent the emulsion from coalescing for the system with 6% by volume oil was 3 mM. For this dilute emulsion, the particle size decreased regularly with an increase in SDS concentration, but the magnitude of the zeta potential went through a strong maximum at intermediate surfactant concentrations.

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Detection Limits of DLS and UV-Vis Spectroscopy in Characterization of Polydisperse Nanoparticles Colloids

Journal of Nanomaterials ◽

10.1155/2013/313081 ◽

2013 ◽

Vol 2013 ◽

pp. 1-10 ◽

Cited By ~ 155

Author(s):

Emilia Tomaszewska ◽

Katarzyna Soliwoda ◽

Kinga Kadziola ◽

Beata Tkacz-Szczesna ◽

Grzegorz Celichowski ◽

...

Keyword(s):

Light Scattering ◽

Dynamic Light Scattering ◽

Point Of View ◽

Spectroscopy Analysis ◽

Force Microscopy ◽

Atomic Force ◽

Transmission Electron ◽

Vis Spectroscopy ◽

The One

Dynamic light scattering is a method that depends on the interaction of light with particles. This method can be used for measurements of narrow particle size distributions especially in the range of 2–500 nm. Sample polydispersity can distort the results, and we could not see the real populations of particles because big particles presented in the sample can screen smaller ones. Although the theory and mathematical basics of DLS technique are already well known, little has been done to determine its limits experimentally. The size and size distribution of artificially prepared polydisperse silver nanoparticles (NPs) colloids were studied using dynamic light scattering (DLS) and ultraviolet-visible (UV-Vis) spectroscopy. Polydisperse colloids were prepared based on the mixture of chemically synthesized monodisperse colloids well characterized by atomic force microscopy (AFM), transmission electron microscopy (TEM), DLS, and UV-Vis spectroscopy. Analysis of the DLS results obtained for polydisperse colloids reveals that several percent of the volume content of bigger NPs could screen completely the presence of smaller ones. The presented results could be extremely important from nanoparticles metrology point of view and should help to understand experimental data especially for the one who works with DLS and/or UV-Vis only.

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