Determination Of Critical Micelle Concentration Research Articles

Interaction of sodium dodecyl sulfate and triton X-100 with ofloxacin drug using conductivity and UV–visible spectroscopic techniques in aqueous alcohols media at several temperatures

The current investigation explores the association and complexation of the mixture of anionic surfactant, sodium dodecyl sulfate (SDS), and antibiotic drug, ofloxacin (OFC) as well as nonionic surfactant, Triton X-100 (TRX) and OFC drug respectively in several additive solutions. The investigations were performed by applying conductivity and UV-Visible spectroscopic techniques. The impacts of drug concentration, types of solvents, and composition of aq. solutions of alcohols (methanol (MeOH), ethanol (EtOH), and 1-propanol (1-PrOH)) as well as temperature change have been investigated on the micelle formation of SDS + OFC mixture. The micellization of SDS + OFC and TRX + OFC systems has been characterized by the determination of critical micelle concentration (CMC) from conductivity vs. SDS concentration (conductivity technique) and Absorbance vs log[TRX] (UV-Visible spectroscopic technique) plots respectively. The micellization of SDS was delayed owing to the introduction of the OFC drug while the effect has been intensified as a function of OFC concentration. At a fixed OFC concentration and temperature, the CMC values were acquired to be augmented with the upsurge of alcohol concentration. The enhancement of the CMC changes has been perceived with the escalation of temperature at a definite concentration of OFC in water and 5% (w/w) aq. alcohols media. The disfavor of micellization of TRX in aq. EtOH solutions in comparison to aqueous solution also detected from UV-Visible spectroscopic technique. The binding constant (Kb) for the complexation of TRX with OFC drug was determined using the Benesi-Hildebrand plot. The Kb values were obtained to be affected by the change of solvent and temperature. The negative free energy change (∆Gmo/ ∆Gbo) of the micellization and complexation demonstrate the spontaneous occurrence of micelle formation and complex development. The enthalpy changes (∆Hmo) of micellization were negative (exothermic process) and entropy changes (∆Smo) were positive (highly disordered and entropy-dominated micellization). Other thermodynamic properties ((∆Hbo and ∆Sbo) and thermodynamics of transfer) have been evaluated and illustrated as well, for the working systems.

Micellar Effect on the Oxidation of Anisaldehyde by Quinolinium Dichromate in Aqueous Acidic Media: A Kinetic Study

Aims: Oxidation of p-anisaldehyde by Quinolinium dichromate (QDC) in the aqueous acetic acid medium in the presence of sulphuric acid using surfactants. Background: The oxidation studies of anisaldehyde is very important as the oxidized products are used as a synthetic intermediate for the preparation of a variety of drugs. Quinolinium dichromate (QDC) has emerged as a very useful and versatile oxidant. Micellar medium enhances the reaction rate. Objective: 1. To study the kinetics of the reaction, which includes the determination of order, rate, and activation parameters. 2. Spectral characterization of QDC by NMR and the kinetic study of the reaction mechanism is done through UV – A visible spectrophotometer. 3. Solvent effect for the oxidation of anisaldehyde by QDC. 4. Determination of critical micelle concentration (CMC) of used surfactants (CTAB and SDS). Methods: The reactions were followed at constant temperature and were followed by monitoring the UV – Visible spectrophotometer (Double Beam – 2203) in a quartz cuvette of 1 cm path length by following the absorbance decay of Cr (VI) at 440 nm. Result: KINETIC RESULTS: 1. The reaction follows first-order dependence on panisaldehyde and QDC. 2. The reaction is found to be acid-catalysed. A plot of log [k] versus log [H+] was found to be a straight line with a slope of 1.07. EFFECT OF SOLVENT: The rate of reaction increases with the increase in acetic acid proportion in the medium, which suggests that the reactions were of the ion–dipole type. MICELLAR EFFECT: 1. Experimental results demonstrated that anionic surfactant SDS catalysed and accelerated the study more effectively than CTAB, which is a cationic surfactant, and the rate of reaction increases with an increase in the concentration of the SDS while in the case of CTAB, the rate decreases with an increase in its concentration. 2. CMC values of CTAB and SDS were 3.9 mM and 8.2 mM, respectively. Conclusion: The value of negative ΔS (entropy of activation) and positive ΔH (enthalpy of activation) suggests the formation of more ordered activated complexes, and the transition state is highly solvated. SPECTROSCOPIC ANALYSIS 1.NMR characterisation of synthesised QDC shows a resemblance with pure QDC. 2. Effect of oxidant QDC, panisaldehyde and acid was studied by considering the spectra of the reaction mixture and varying their concentration.

Carbon quantum dots as fluorescent probes in the measurement of the critical micelle concentration of surfactants

The critical micelle concentration (CMC) is one main parameter of surfactants, so an accurate, rapid, and convenient method for CMC determination is of great significance for surfactant applications. In this paper, three samples of carbon quantum dots (CQDs) with different fluorescence properties were developed as fluorescent probes for the CMC determination of CTAB, SDS, Triton X-100, perfluoro OBS and Pluronics® P-123. The fluorescence excitation and emission spectra of a constant amount of the CQDs in different concentrations of the surfactant solution were recorded, and then the CMC values of the surfactant were deduced from the fluorescence intensity change and the Stokes shift variation. The obtained CMC data using three samples of the CQDs agree well with those in the published literature. It is also demonstrated that in the micellization process the interaction between the CQDs and the surfactant molecules is complicated, because the fluorescence properties of the CQDs are found to be related to the characteristics of the CQDs, the head group type of ionic surfactants, the chemical structure between the hydrophobic and hydrophilic segment, and the chemical nature of the hydrophobic chains of the surfactants. So, the CQDs are demonstrated to be located at the palisade layer in the surfactant micelles due to the surface-attached polar groups on the CQDs although the CQDs are mainly hydrophobic as fluorescent probes. The fluorescent CQDs are considered to be new choices of the fluorescent probes in the facile CMC measurement of the surfactants.

Facile determination of surfactant critical micelle concentration through dried drop “coffee-ring” image analysis

Surfactants serve a myriad uses as key components of household cleaning, personal care, and cosmetics products, and they are important too in the food, textiles, plastics, oil, agrochemical, and pharmaceutical industries. The majority of those currently in use, however, are fossil fuel-derived and are environmentally unfriendly and/or bio-incompatibly toxic/irritant. There are significant efforts thus now expended in the search for alternatives that are generally “greener”. The concentration at which such compounds self-assemble to form micelles – their so-called critical micelle concentration – is one of their key physicochemical characteristics, and the experimental determination of this is central to their development both as analytical tools and as commercial materials. In the following report a methodology is presented that provides for a fast, non-expensive, and potentially high throughput means to determine surfactant critical micelle concentration, utilizing a simple dried drop “coffee-ring” image analysis.

Dynamic light scattering for the determination of linoleic acid critical micelle concentration. Effect of pH, ionic strength, and ethanol

The present work proposes the use of Dynamic Light Scattering (DLS) to characterize aqueous solutions containing linoleic acid (LA). The parameters affecting CMC, particle size and distribution are studied. In a 0.2 M borate buffer, a CMC value of 0.13 ± 0.01 mM was found, with particle size increasing from 200 to 800 nm with LA concentration. It appears that increasing the pH does not simply affect the CMC value but also modifies the stabilization of the particles. At pH 9, the medium is monodisperse and, at the highest LA concentrations studied, vesicle formation is suspected. At pH values around 10-11, the medium is polydisperse due to the dynamic equilibrium of micelle formation/disintegration. The counter ion concentration (Na+) has a significant effect on the particles size and number. The addition of ethanol also has an effect on the stability of the particles and leads to a decrease of the particle size without significantly affecting the CMC value.

Determination of Critical Micelle Concentration of Sodium Dodecyl Sulfate in Distilled Water at 298.15K by Surface Tension Measurements

Surfactants are chemicals that adsorb to the interface between a solution and another phase (gases or solids) and self-assemble molecular clusters known as micelles in a solution (water or oil phase). Measurements of the surface tension of sodium dodecyl sulfate (SDS) in distilled water at 298.15K are reported. The increase of concentration of sodium dodecyl sulfate (SDS) in distilled water then decreased in surface tension at 298.15K. Critical micelle concentration (CMC) decreased with a decrease in surface tension. The graphs of surface tension versus concentration were made to determine the CMC of the solution.

Determination of the Second Critical Micelle Concentration of Aqueous Non-Ionic Surfactants: Measurement and Calculation of Various Physicochemical Properties above the First CMC Point

Determination of the Second Critical Micelle Concentration of Aqueous Non-Ionic Surfactants: Measurement and Calculation of Various Physicochemical Properties above the First CMC Point

CMC determination and thermodynamic changes of the mixture of mefenamic acid drug with surfactant (Tween 60, Tween 80, And TritonX-100) in aqueous solution

Surface tension of non-steroidal anti-inflammatory drugs (NSAIDs) such as mefenamic acid was measured at concentrations (10-1, 10-2, 10-3, 2x10-3M) carrying the surfactant active agent such as sorbitan monostearate (Tween 60) and Oxyethylene (20) sorbitan mononuclear (Tween 80) as well as with (Triton X-100) at concentrations from 10-1M to 10-4M using a plate-type tensiometer, as well, the effect of temperatures at (323,313,303,293) K were studied. The critical micelle concentration (CMC) was evaluated from the plot of surface tension with the concentrations, and the thermodynamic constants were estimated at CMC such as the change in enthalpy heat content (ΔH°m), the change in the free energy of adsorption (ΔG°ads) and the change in free energy for the formation of micelles (ΔG°m) as well as the change in entropy (ΔS°m).

CMC determination and thermodynamic changes of the mixture of non-steroidal anti-inflammatory drug (mefenamic acid) with anionic surfactant (SDS), and cationic surfactant (CTAB) in aqueous solution

Surface tension was measured using a platinum plate of the tensiometer for aqueous solutions of non-steroidal anti-inflammatory drugs (NSAIDs) such as mefenamic acid in concentrations of (10-3,10-2,10-10 M) to study the effect of adding surfactants on the drug solubility, which are anionic surfactant such as sodium dodecyl sulfate (SDS) and cationic surfactant such as cetyltriamonium bromide (CTAB) concentrations within range (1x10 -3 -1x10 -1 M). The effect of temperature at (313,303,293,283 K) on these aqueous solutions with Mefenamic acid has also been studied. From the plot of the concentration of aqueous solutions of surfactants with drug versus surface tension (ɣ) were obtained the critical micelle concentration (CMC). As well, the values of the Gibbs surface excess concentration (Γmax), minimum area occupied per molecule (Amin.), surface pressure at CMC (Πcmc) were determined on basis of the standard Gibbs free energy of adsorption (ΔG°ads) and the thermodynamic constants (ΔHm, ΔSm, ΔGm, ΔGads) were found at CMC for aqueous solutions.

On the determination of critical micelle concentration of partially dissociated ionic surfactants using contact angle data

The contact angle (CA) data has been utilized for determining the critical micelle concentration (cmc) of fully dissociated surfactant SDS, but not for nonionic surfactants Triton X-100 and C12E6 [Thu et al., J.Mol.Liq (2019) 111582]. Could this approach work for a partially dissociated ionic surfactant such as dodecyltrimethylammonium bromide (DTAB)? To verify this, this work studied the evaporation process of DTAB(aq) solution drops on parafilm. The relaxations of CA, wetting diameter, and drop volume were recorded during evaporation to determine the advancing/receding (θa and θr) CA’s. The data revealed that the breakpoints of θa and θr matched well with the cmc from the ST data; thereby, confirming that the aforementioned approach is viable for a partially dissociated ionic surfactant. Additional examination of the relaxation data and drop profiles revealed that the movement of a solution drop’s triple line (pinning-depinning behavior) during the evaporation process is primarily dependent on the localized surface morphology.

Robust Superhydrophobic Brass Mesh with Electrodeposited Hydroxyapatite Coating for Versatile Applications.

A robust superhydrophobic brass mesh was fabricated based on a low-energy surface and a roughness on the nano/micro-meter scale. It was carried out by the forming of hydroxyapatite (HP) coatings on its surface through a constant current electro-deposition process, followed by immersion in fluoroalkylsilane solution. Surface morphology, composition and wetting behavior were investigated by field-emission scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), high speed camera, and contact angle goniometer. Under optimal conditions, the resulting brass mesh exhibited superhydrophobicity, excellent anti-corrosion (η = 91.2%), and anti-scaling properties. While the surfactant liquid droplets of tetradecyl trimethyl ammonium bromide (TTAB) with different concentration were dropped on the superhydrophobic surface, maximum droplet rebounding heights and different contact angles (CAs) were observed and measured from side-view imaging. The plots of surfactant-concentration−maximum bounding height/CA were constructed to determine its critical-micelle-concentration (CMC) value. Close CMC results of 1.91 and 2.32 mM based on the determination of maximum rebounding height and CAs were obtained. Compared with its theoretical value of 2.1 mM, the relative errors are 9% and 10%, respectively. This indicated that the novel application based on the maximum rebounding height could be an alternative approach for the CMC determination of other surfactants.

Production and functional stability of the biourfactant isolated from Stenotrophomonas maltophilia UCP 1601

The present study investigated the production of biosurfactant by Stenotrophomonas maltophilia UCP 1601under submerse fermentation using renewable substrates as carbon and nitrogen sources applying two statistical tools as Plakket-Burman experimental design and full factorial design to optimize the bioprocess. A partial characterization was performed by measuring the surface tension, emulsification index, determination of CMC, ionic charge. The biosurfactant was tested to different conditions of temperature, pH and salinity, in order to evaluate the stability of the biomolecule. The surface tension of the biosurfactant produced using corn steep liquor and glycerol was 27 mN/m, whose yield was 12.6 g/L, and its character is anionic. The critical micelle concentration (CMC) was 70% using the cell-free metabolic liquid. The biosurfactant was able to emulsify 56% of the burned engine oil. The biomolecule showed high functional stability and performance under extreme conditions of thermal, pH and saline concentrations stability. All determinations carried out confirm the generation of a stable, efficient bioproduct that contributes to the circular bioeconomy and the great potential for remediation under harsh environmental conditions.

Impacts of oil components on the stability of aqueous bulk CO2 foams: An experimental study

Study of foam stability in the presence of oil components is mainly devoted to the impacts of aliphatic components like short- and long-chained alkanes. In this study, several experiments, including critical micelle concentration (CMC) determination, IFT measurement, high pressure bulk foam stability as well as foam texture visualization and analysis have been designed and performed in the presence of various oil solution samples to explore the impacts of aromatic components and compare them with the impacts of aliphatic components on CO2 foam stability. Alpha-Olefin-Sulfonate (AOS) surfactant solutions with different concentrations of surfactant in the presence of various synthetic oil solutions comprising toluene and n-heptane were prepared to compare the interfacial behavior and performance of the surfactant solutions containing aromatic and aliphatic components with regards to foam stability. The results revealed that, due to higher micellar solubilization of the n-heptane as the aliphatic component compared to toluene, surfactant surface activity would be more detrimentally impacted by the presence n-heptane. Employing electrical conductivity measurements, it was observed that the CMC of surfactant solutions with addition of 1 vol% of toluene and n-heptane to the surfactant solution, increased by 15 and 19 times, respectively. Increase in surfactant concentration in solutions above CMC with no oil compound, did not show any promising improvement on foam stability. However, in the presence of different oil additives, increase in surfactant concentration from 0.1 wt% to 0.5 wt% resulted in the increase in foam stability by 45% on average measured by foam half-life time where the foam was generated by aeration method. This observation was further validated by the decrease in IFT, measured by spinning drop method, from the average range of 1.4 mN/m for different oil solutions to 0.6 mN/m by increasing surfactant concentration from 0.1 wt% to 0.5 wt%. IFT measurements between surfactant solutions and different oleic samples with oil components suggested that the presence of higher n-heptane in oil solutions resulted in higher IFT. Similar behavior was observed in foam stability measurements. Generally, addition of oil components to the foam solution resulted in lower foam stability. That is, higher oil content concentration would result in lower foam stability. Also, the presence of n-heptane had more detrimental impacts on foam stability compared to the presence of toluene. The texture of the resulted foam in the presence of toluene and n-heptane was visualized. It was observed that the texture of the foam generated in the presence of toluene had smaller bubble size compared to that in the presence of n-heptane. Also, it was observed that as time passes, oil droplets migrate from lamellae to the plateau borders, resulting in lamellae thinning and foam bubble coarsening and rupture.

Micellization, surface activities, and thermodynamic studies on the ionic liquid in the presence of vitamins

Surface active ionic liquids (SAILs) are classified as a significant class of ionic surfactants that display superior surface properties compared to conventionally available ionic surfactants. The micellization properties of these liquids can be tailored in the presence of various additives (surfactants/drugs/vitamins/amino acids/carbohydrates). But there are few studies on the investigation of micellization of ionic liquid in the presence of vitamins. Considering this, the conductivity and surface tension measurements have been done to study the influence of vitamins (thiamine hydrochloride(ThHCl)/pyridoxine hydrochloride(PyHCl);) on the micellar and surface properties of ionic liquid [C15mim] [Br] at various concentrations (0.01, 0.05, and 0.1) mM and temperatures (298.15–318.15) K. The properties comprise determination of critical micelle concentration, micellization parameters, surface excess concentration, minimum area per molecule, and Gibbs free energy of adsorption. The main objective is to learn the interactions occurring between ionic liquids and these biomolecules along with the utilization of these ionic liquids in biomedical science, drug delivery, and bio industries.

CD44/Folate Dual Targeting Receptor Reductive Response PLGA-Based Micelles for Cancer Therapy.

In this study, a novel poly (lactic-co-glycolic acid) (PLGA)-based micelle was synthesized, which could improve the therapeutic effect of the antitumor drug doxorubicin hydrochloride (DOX) and reduce its toxic and side effects. The efficient delivery of DOX was achieved by active targeting mediated by double receptors and stimulating the reduction potential in tumor cells. FA-HA-SS-PLGA polymer was synthesized by amidation reaction, and then DOX-loaded micelles were prepared by dialysis method. The corresponding surface method was used to optimize the experimental design. DOX/FA-HA-SS-PLGA micelles with high drug loading rate and encapsulation efficiency were prepared. The results of hydrophilic experiment, critical micelle concentration determination, and hemolysis test all showed that DOX/FA-HA-SS-PLGA micelles had good physicochemical properties and biocompatibility. In addition, both in vitro reduction stimulus response experiment and in vitro release experiment showed that DOX/FA-HA-SS-PLGA micelles had reduction sensitivity. Molecular docking experiments showed that it can bind to the target protein. More importantly, in vitro cytology studies, human breast cancer cells (MCF-7), human non-small cell lung cancer cells (A549), and mouse colon cancer cells (CT26) were used to demonstrate that the dual receptor-mediated endocytosis pathway resulted in stronger cytotoxicity to tumor cells and more significant apoptosis. In and in vivo antitumor experiment, tumor-bearing nude mice were used to further confirm that the micelles with double targeting ligands had better antitumor effect and lower toxicity. These experimental results showed that DOX/FA-HA-SS-PLGA micelles have the potential to be used as chemotherapeutic drugs for precise tumor treatment.

Accurate and sensitive probing of onset of micellization based on absolute aggregation‐caused quenching effect

AbstractProbing the onset of micellization, or determining the critical micelle concentration (CMC), is of crucial importance while remains to be challenged by growing demand for extraordinary sensitivity and accuracy. Although fluorometry has attracted wide attention owing to its superiority in simplicity and sensitivity over other methods, the presence and fluctuation of background fluorescence of conventional fluorescent probes undermine the accuracy of CMC determination. Herein, a series of novel fluorescent probes without background fluorescence at a concentration below CMC owing to absolute aggregation‐caused quenching (aACQ) are utilized for sensitive and accurate measurement of CMC. The aACQ probes aggregate spontaneously and instantly in an aqueous environment owing to molecular π–π stacking with fluorescence quenching absolutely. Therefore, the absence of background fluorescence at a concentration below CMC clears relevant interference associated with conventional fluorophores. In this study, the new method is applied for versatile surfactants with CMCs ranging from nanomolar to millimolar concentrations, especially copolymers with ultralow CMC. The higher sensitivity and accuracy are highlighted by comparison with conventional probes.

Physicochemical and electrochemical methods for determination of critical micelle concentrations of surfactants: a comprehensive review

Physicochemical and electrochemical methods for determination of critical micelle concentrations of surfactants: a comprehensive review

Dual emissive amphiphilic carbon dots as ratiometric fluorescent probes for the determination of critical micelle concentration of surfactants.

The sensitive determination of the critical micelle concentration (CMC) of surfactants is very important for their practical application. Due to their good sensitivity and simple operation, pyrene and its derivatives have been widely used as fluorescent probes to detect the CMC. However, their virulent and poor water-soluble nature has limited their wide employment. In the present work, environmentally friendly amphiphilic carbon dots (Cdots) with dual-color emission and absolute quantum yield (PLQY) values higher than 50% have been fabricated through a solvothermal process, which could successfully serve as self-calibrative, ratiometric fluorescent probes to estimate the CMC of both non-ionic and ionic surfactants. This work not only provides a new strategy to design green ratiometric fluorescent probes for the CMC measurement of surfactants but also expands the application of Cdots in the colloidal field.

Determination of the critical micelle concentration of surfactants using fluorescence strategies.

The increasing importance of surfactants in various fields has led to growing interest in the comprehensive characterization of surfactants. The critical micelle concentration (CMC), the most fundamental property of surfactants, is a parameter that must be measured. In particular, with the continuous expansion of the molecular structure of surfactants, numerous novel amphiphilic molecules have been developed that are capable of forming ordered aggregates in various solvent systems. Fluorescence spectroscopy, based on the differences in fluorescence intensity and wavelength of the fluorescent probe in the solvent phase and micellar phase, can sensitively detect the CMC of surfactants. This review aims to summarize the various fluorescence methods used to determine the CMC, including aggregation-induced emission (AIE), excimer formation, intramolecular charge transfer (ICT), and other miscellaneous strategies. The difficulties and limitations in the CMC determination process are also described. Further suggestions are provided to guide the existing fluorescence probes and the corresponding fluorescence methods to detect critical aggregation concentrations of amphiphilic molecules.

Effects and mechanism of epimedium polysaccharide on solubility of icariin and baohuoside Ⅰ

This study evaluated the effects of epimedium polysaccharide(EPS) on the solubility of icariin and baohuoside Ⅰ so as to preliminary explore its solubilization function and the underlying mechanism. The solubility of these two insoluble flavonoids in water and polysaccharide solutions was compared by high performance liquid chromatography, and the mechanism was investigated by diffe-rential scanning calorimetry(DSC) and critical micelle concentration determination. The results indicated that their solubilization in crude EPS solutions was concentration-dependent. The solubility of icariin and baohuoside Ⅰ in 20 mg·mL~(-1) EPS-1-1 was 9.05 times and 5.76 times that in water, respectively; while their solubility in 20 mg·mL~(-1) EPS-2-1 was 10.55 and 8.39 times that in water, respectively. The change of the DSC thermograms suggested the formation of new complexes from icariin and baohuoside Ⅰ with polysaccharides. The critical micelle concentrations proved the micellar properties of both EPS-1-1 and EPS-2-1. In short, EPS can significantly increase the solubility of icariin and baohuoside Ⅰ, the mechanism of which may be related to the formation of micellar complexes between EPS and insoluble flavonoids.