Direct Evidence for β-Cyclodextrin-Induced Aggregation of Ionic Surfactant below Critical Micelle Concentration

1994 ◽  
Vol 48 (11) ◽  
pp. 1428-1431 ◽  
Author(s):  
Yun-Bao Jiang ◽  
Xiu-Juan Wang
Keyword(s):  
Critical Micelle Concentration ◽  
Cetyltrimethylammonium Bromide ◽  
Surfactant Concentration ◽  
Direct Evidence ◽  
Sodium Dodecylsulfate ◽  
Fluorescence Emission ◽  
Peak Height ◽  
Ionic Surfactant ◽  
Fixed Amount ◽  
Induced Aggregation

The fluorescence emission of p-dimethylaminochalcone (DMAC) has been monitored in β-cyclodextrin (β-CD) and cetyltrimethylammonium bromide (CTMAB) or sodium dodecylsulfate (SDS) mixture. In the presence of a fixed amount of β-CD, a peak-shaped variation is observed in the curve of DMAC fluorescence intensity vs. surfactant concentration below critical micelle concentration (cmc). The peak height is dependent on β-CD concentration, and no peak is noted in the absence of β-CD. Such a peak-shaped variation in DMAC fluorescence emission is shown to be direct evidence for β-CD-induced aggregation of the surfactant below cmc in aqueous solution. The 1:1 surfactant/β-CD inclusion complex is the hydrophobic source inducing the aggregation.

scholarly journals Synthesis and characterization of alkyl polyglucoside surfactant: A pilot tool to industrial applications

2021 ◽  
Author(s):  
CI Chemistry International
Keyword(s):  
Critical Micelle Concentration ◽  
Surfactant Concentration ◽  
Industrial Applications ◽  
Industrial Processes ◽  
Synthesis And Characterization ◽  
Ionic Surfactant ◽  
Uv Visible ◽  
Gas Chromatography Mass Spectroscopy ◽  
Alkyl Polyglucoside

In this study, alkyl polyglucoside surfactant was synthesized and the critical micelle concentration (CMC) was determined. The synthesized product was quantified using Gas Chromatography-Mass Spectroscopy (GC-MS). The CMC of the surfactant was evaluated using UV-visible Spectrophotometer. The critical micelle concentration (CMC) value was obtained from the sharp break in the plot of absorbance measurements versus surfactant concentration. The critical micelle concentration (CMC) of the surfactant was found to be 0.50 mol/dm3. This result showed a precise value for the CMC of non-ionic surfactant; since the value of the CMC obtained was lower than the stock solution of the surfactant prepared. The standard change in Gibbs free energy of the micelle (ΔGoCMC) showed that the process was feasible and spontaneous having the value of − 1.716 kJ/mol. This study recommends that akyl polyglucoside should be widely used for both domestic and industrial processes in view of the environmentally friendly nature, which are safe to use partially.

scholarly journals Influence of the Hamaker Constant on the Value of the Critical Thickness of Foam Films

Coatings ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 576
Author(s):  
Dilyana Ivanova-Stancheva
Keyword(s):  
Experimental Data ◽  
Critical Micelle Concentration ◽  
Cationic Surfactant ◽  
Surfactant Concentration ◽  
Critical Thickness ◽  
Hamaker Constant ◽  
Ionic Surfactant ◽  
Interferometric Method ◽  
Foam Films ◽  
Average Value

The aim of the present study was to check the influence of the Hamaker constant (A(h)) on the calculated critical thickness of foam films. It was done by a comparison between the experimental data of the critical thickness and the theoretically obtained data with different values of (A(h)), which take part in the equations of Radoev, Scheludko, Manev, and Vrij. We calculated the latter for film thicknesses from 15 to 70 nm based on several equations. We used the experimental data of hcr (average value of critical thickness and measured once, in the place of a spot appearance) for foam films stabilized by non-ionic surfactant n-dodecyl-β-D-maltoside (C12G2) or by cationic surfactant n-dodecyl trimethylammonium bromide (C12TAB), as measured by the interferometric method. The foam films were produced from solutions with surfactant concentration at CMC (Critical Micelle Concentration) in the presence of 0.1 M NaBr. For films of C12G2, the best correspondence was found between measured hcr (in the spot) and calculated ones by the RShM equation using effective A(h) (introduced by Coons et al.) or Vassilieff’s values, but with a correction for the added electrolyte. For films stabilized by C12TAB, a difference between the measured and theoretically calculated hcr was found, which was probably due to the nature of the surfactant. Nevertheless, this difference was smallest when calculated hcr values were obtained with data for Aeff (h) and Vassilieff’s A(h) constant, respectively.

The Role of Surfactant Concentration on the Aqueous Stability of a Mono-Azo Disperse Dye

1976 ◽  
Vol 46 (4) ◽  
pp. 250-260 ◽  
Author(s):  
B. H. Knox ◽  
H.-D. Weigmann
Keyword(s):  
Critical Micelle Concentration ◽  
Surfactant Concentration ◽  
Sodium Dodecylsulfate ◽  
Disperse Dye ◽  
Stable Dispersion ◽  
Dispersion Technique ◽  
Dye Solubilization

The aqueous stability of a mono-azo disperse dye (Resolin Red BBL) is measured as a function of concentration of sodium dodecylsulfate (NaDDS) at 95°C. The rates of dye solubilization, aggregation, and degradation are measured and related to the concentration of NaDDS and to the critical micelle concentration (CMC). Dye stability decreases sharply for concentrations of NaDDS greater than the CMC passing through a minimum at 0.2% NaDDS (2 X CMC) and increases for concentrations of NaDDS greater than 0.2%. The rate of dye solubilization at low surfactant concentrations (<0.3%) is observed to be very slow, taking 9 days to reach a stable dispersion for 0.2% NaDDS. The rate of dye solubilization is greatly increased by initially dissolving the dye in a volatile solvent, such as acetone, referred to as the solvent dispersion technique.

Effect of cetyltrimethylammonium bromide on the electrochemiluminiscence and electrooxidation of luminol

1983 ◽  
Vol 48 (2) ◽  
pp. 477-483 ◽  
Author(s):  
Jan Lasovský ◽  
František Grambal
Keyword(s):  
Cetyltrimethylammonium Bromide ◽  
Linear Sweep Voltammetry ◽  
Critical Micellar Concentration ◽  
Peak Height ◽  
Anodic Peak ◽  
Alkaline Solutions ◽  
Platinum Electrodes ◽  
Micellar Solutions ◽  
Linear Sweep ◽  
Low Concentrations

The electrooxidation of luminol in alkaline solutions in the presence of cetyltrimethylammonium bromide (I) was studied by linear sweep voltammetry on fixed and vibrating platinum electrodes. The presence of I in low concentrations (below the critical micellar concentration) brings about aggregation of the luminol, which is manifested by an increase in the anodic peak height and its shift towards lower potentials. In micellar solutions the peak height decreases owing to the slower diffusion of the bulkier micelles, the shift to lower potentials being preserved. The light-voltage curves correspond with the voltammetric curves, exhibiting identical shifts of the peak potentials in dependence on the concentration of the surfactant.

Surface Activity Research of Cationic Gemini Surfactants

2013 ◽  
Vol 690-693 ◽  
pp. 2076-2080
Author(s):  
Zhen Zhong Fan ◽  
Lan Lan Li ◽  
Li Feng Zhang ◽  
Qing Wang Liu
Keyword(s):  
Surface Tension ◽  
Critical Micelle Concentration ◽  
Surface Activity ◽  
Surfactant Concentration ◽  
Gemini Surfactant ◽  
Gemini Surfactants ◽  
Ph Value ◽  
Inorganic Salts ◽  
Cationic Gemini Surfactant ◽  
Cationic Gemini Surfactants

Cationic Gemini surfactant concentration, the inorganic salts added and the pH value of surface tension obtained cationic gemini surfactant critical micelle concentration is 0.4mmol / L;by adding three kinds of inorganic salts NaCl, MgCl2, and Na2SO4 ,which Na2SO4 has the greatest impact on surface tension, followed by MgCl2.The surface minimum tension of the pH ranged from 9 to 11 , indicating that the surface activity of cationic gemini surfactants achieved the highest.

scholarly journals Thermal behaviour of different non-ionic surfactant concentration on the polymeric membrane

2021 ◽  
Vol 1874 (1) ◽  
pp. 012059
Author(s):  
B BadrulHaswan ◽  
A R Hassan ◽  
K Ali ◽  
A A M Redhwan ◽  
A Nasir
Keyword(s):  
Thermal Behaviour ◽  
Surfactant Concentration ◽  
Polymeric Membrane ◽  
Ionic Surfactant

Influence of Surfactant Concentration on Laser-Based Gold Nanoparticle Formation and Stability

2012 ◽  
Vol 65 (2) ◽  
pp. 97 ◽  
Author(s):  
Yuen-Yan Fong ◽  
Jason R. Gascooke ◽  
Gregory F. Metha ◽  
Mark A. Buntine
Keyword(s):  
Critical Micelle Concentration ◽  
Laser Irradiation ◽  
Gold Nanoparticle ◽  
Sodium Dodecylsulfate ◽  
Formation Kinetics ◽  
Transmission Electron ◽  
Bulk Gold ◽  
Microscopy Images ◽  
Apparent Influence

The time evolution of gold nanoparticle (AuNP) yields by in-situ laser irradiation from bulk gold in aqueous solutions containing the surfactant sodium dodecylsulfate (SDS) at concentrations above and below the critical micelle concentration in water is reported. These studies are augmented by transmission electron microscopy images of AuNP samples at each SDS concentration recorded after 90 min of laser irradiation. The results show that while a low concentration of SDS plays a role in the formation kinetics, there is no apparent influence of the SDS concentration around the surfactant critical micelle concentration on particle size during AuNP production.

scholarly journals Dispersions of Metal Oxides in the Presence of Anionic Surfactants

2018 ◽  
Vol 3 (1) ◽  
pp. 3 ◽  
Author(s):  
Leszek Ruchomski ◽  
Edward Mączka ◽  
Marek Kosmulski
Keyword(s):  
Metal Oxides ◽  
Surfactant Concentration ◽  
Critical Concentration ◽  
Supporting Electrolyte ◽  
Sodium Dodecyl ◽  
Sodium Dodecylsulfate ◽  
Solubility Limit ◽  
Ionic Surfactants ◽  
Liquid Ratio ◽  
High Concentration

We studied the behavior of dilute dispersions of nanoparticles of hematite, alumina, and titania in the presence of various concentrations of very pure sodium dodecyl-, tetradecyl-, and hexadecylsulfate. The concentrations studied were up to critical micelle concentration (CMC) for sodium dodecylsulfate, and up to the solubility limit in case of sodium tetradecyl- and hexadecylsulfate. The dispersions were adjusted to different pH (3–11), and 10−3 M NaCl was used as the supporting electrolyte. The solid-to-liquid ratio was strictly controlled in all dispersions, and the behavior of fresh dispersions was compared with dispersions aged for up to eight days. The presence of very low concentrations of ionic surfactants had rather insignificant effects on the ζ potentials of the particles. At sufficient concentrations of ionic surfactants the isoelectric point (IEP) of metal oxides shifted to low pH, and the long-chain surfactants were more efficient in shifting the IEP than their shorter-chain analogues. Once the surfactant concentration reached a critical value, the ζ potentials of the particles reached a pH-independent negative value, which did not change on further increase in the surfactant concentration and/or aging of the dispersion. This critical concentration increases with the solid-to-liquid ratio, and it is rather consistent (for certain oxides and certain surfactants) when it is expressed as the amount of surfactant per unit of surface area. Surprisingly, the surfactant-stabilized dispersions always showed a substantial degree of aggregation; that is, the particle size observed in dispersions by dynamic light scattering was higher than the size of particles observed in dry powders by electron microscopy. Apparently, in spite of relatively high ζ potentials (about 60 mV in absolute value), the surfactant-stabilized dispersions consist of aggregates rather than of primary particles, and in certain dispersions the high concentration of surfactant seems to induce aggregation rather than prevent it.

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