Critical Concentration Of Micelle Formation Research Articles

Solubilization of n-hexadecane by micellar solutions of trehalolipid - surfactants of biological origin

Objectives. To isolate biosurfactants of glycolipid nature produced by oil hydrocarbon degrading bacteria and to establish their ability to solubilize hydrophobic compounds in the case of n-hexadecane.Methods. Trehalolipids were isolated from bacteria Rhodococcus erythropolis X5 (VKM Ac-2532 D) and Rhodococcus erythropolis S67 (VKM Ac-2533 D) included in the MikroBak biopreparation for the bioremediation of oil-contaminated territories. The genome of R. erythropolis X5 is deposited in the National Center for Biotechnology Information database under GenBank accession numbers CP044283 and CP044284, BioSample – SAMN12818508, BioProject – PRJNA573614, and SRA – PRJNA573614. The content of trehalolipid biosurfactants was estimated by the amount of trehalose in aqueous solutions of biosurfactants using the phenolsulfur method. The surface tension of the obtained aqueous solutions of biosurfactants was determined by the du Noüy ring method using a Kruss K6 tensiometer (Kruss, Germany). The critical concentration of micelle formation was determined by the inflection point on the curves of surface tension dependence on the concentration of the biosurfactant solution. In order to establish the solubilizing ability of biosurfactants, the residual concentration of n-hexadecane in an aqueous sample of different concentrations was determined using a gas chromatographic method of analysis.Results. At a constant surface tension of 24.2 mN/m and 25.0 mN/m for R. erythropolis X5 and R. erythropolis S67, respectively, the critical micelle concentration for both strains was 33 mg/L (3.8 ∙ 10−5 mol/L). The solubilizing effect of Rhodococcus trehalolipid micellar solutions against hydrophobic n-hexadecane was demonstrated by gas chromatographic analysis. The solubilization process was characterized using molar solubilization capacity (Sm), molar solubilization ratio (MSR), micelle–water partition coefficient (Km), and solubilization energy 0 (ΔGS ). It was shown that the solubilization process of n-hexadecane proceeds spontaneously 0 (ΔGS = −35.5 kJ/mol) and more efficiently (Sm = 4.3 mol/mol, MSR = 4.7 mol/mol) than in comparison with other biosurfactants of glycolipid nature.Conclusions. Based on the value of the molar solubilization coefficient, it can be concluded that trehalolipids of the R. erythropolis X5 strain solubilize n-hexadecane in aqueous solutions to a greater extent than compared to other biosurfactants of a glycolipid nature, but are inferior to synthetic surfactants.

SYNTHESIS OF SURFACTANTS FROM NATURAL RAW MATERIALS

This article presents a surfactant synthesized from a mixture of palmitic, oleic, and stearic acids obtained by the distillation and fractionation of oils and fats, as well as ethanol. The synthesis was carried out in 4 stages, which involved the initial formation of an acid mixture, followed by esterification, sulfonation, and ultimately saponification. The composition of the fatty acid mixture was analyzed using chromatography, revealing that palmitic acid makes up the largest proportion at 64.3%, followed by oleic acid at 29.1%. The structure and properties of the surfactant were investigated using modern methods and instruments. The average particle size of the surfactant indicates that it can be classified as a highly dispersed system, with particle diameters ranging from 10 nm to 1 μm. It was observed that the particle size of the surfactant increases once the critical concentration of micellization is reached. The stability of the system in the substance is indicated by a ζ-potential that falls outside the range of 30 mV < ζ < -30 mV. The resulting product exhibits good surface-active properties such as detergency, emulsification, wetting, and foaming ability. According to hydrophilic-lipophilic balance calculations, the synthesized surfactant is classified as a detergent. It demonstrates a high ability to remove pigment-oil and protein contamination at a concentration of 4.0 g/dm3, regardless of the fabric type. Additionally, it was found that the synthesized surfactant exhibits significant emulsifying ability towards industrial oils. The analysis of the surface tension of the surfactant showed that its critical concentration for micelle formation is 4.0 g/dm3. The surfactant demonstrates high wetting abilities on both hydrophilic and hydrophobic surfaces. The foaming properties of the surfactant are satisfactory compared to known surfactants from petrochemical raw materials. Moreover, stable foaming is observed, which directly depends on the surfactant concentration. For citation: Lutfullina G.G., Valeeva E.E. Synthesis of surfactants from natural raw materials. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2024. V. 67. N 6. P. 45-54. DOI: 10.6060/ivkkt.20246706.6984.

Studying the influence of additives of cationic latex and basalt fiber on the calculated characteristics of stone-sand mixtures made of iron tailings reinforced with cement

Problem. As a major industrial solid waste, iron tailings not only occupy a lot of agricultural land, but also pollute the environment. It is necessary to study the effect of adding different concentrations of aqueous cationic latex and different lengths of basalt fibers to the composition of crushed stone-sand mixtures of iron tailings and cement on the parameters of flexural ultimate tensile strength and the characteristics of the modulus of elasticity calculation. Goal. The effect of additives of aqueous cationic latexes of different concentrations and basalt fiber of different lengths in the composition of crushed stone-sand mixtures of iron tailings with cement on the flexural tensile strength and the elastic modulus as design characteristics was investigated. Methodology. The first stage of the study was to determine the effect of the content of two cationic latexes on the values of the tensile strength in flexion and the elastic modulus of the material from CSM-40 made of iron tailings reinforced with cement. The content of Butonal NS 198 and Butonal 5126 latexes in the composition of CSM-40 was 0, 3, 5, and 10 % by weight of the optimal amount of water at the maximum density of the mixture with cement. At the second stage, the influence of the length of basalt fibers at their content of 0.05 % by weight of the crushed stone and sand mixture on the values of the flexural tensile strength and the elastic modulus of the material from the cement-reinforced iron tailings CSM-40 was studied. It has been established that the addition of cationic latexes of the Butonal series to the composition of crushed stone-sand mixtures of iron tailings with cement causes a moderate increase in the values of the flexural tensile strength and the elastic modulus, compared to the material without the addition of latexes. Experimentally, a more significant increase in the values of the flexural tensile strength and elastic modulus of fiber-reinforced materials made of crushed stone-sand mixtures of iron tailings with cement was found compared to materials modified with cationic latexes. Conclusions:1.When the latex content is 5% (equivalent to the critical concentration of micelle formation in aqueous solution), the flexural tensile strength can be increased by a maximum of 14-15%. Under similar conditions, the elastic modulus value increases by 12-18%. 2.The addition of 0.05% (by weight) basalt fiber to the crushed stone and sand mixture of rust-colored quartzite reinforced with cement improves the bending strength and elastic modulus values compared to the non-fiber material. The largest increases in flexural tensile strength (18.5%) and elastic modulus (27.1%) are for materials with basalt fiber lengths of 18 mm.

Исследование композитов для создания стабильной красящей пищевой системы эмульсионного типа

Composites to create a food system of the W/O emulsion type with a maximum yield of coloring substances were determined. Refined deodorized sunflower oil, beet juice and its concentrates with a dry matter content of 12.23; 18.73; 30.12 and 64.61, a mixture of mono-, diglycerides and glycerin were studied. By gas chromatography, the mass fraction of fatty acid in sunflower oil was determined from the sum of saturated, mono- and polyunsaturated fatty acids, including palmitic (6.5%), oleic (20.9%), and linoleic (66.4%). The content of betanin, conformational changes in mono-, di- and polysaccharide components, and the presence of peptide structures were determined by spectrophotometric methods in beet juice and concentrates. Flow curves of composites for the emulsion were studied by rheometric methods, and interfacial tension was studied by the hanging drop method. To check the physical and sensory properties of the emulsion, the selected composites were dispersed: sufficient conditions for the process were set for its duration – 10 minutes at a rotation speed of 6000 rpm. It is shown that, to create a food emulsion W/O with stable color characteristics during storage, beet juice concentrates with a dry matter content of 64.61% and betanin 0.54% can be used as a dispersed phase. The critical concentration of micelle formation of the emulsion is achieved by adding 0.5% surfactant. The phenomenon of syneresis at a storage temperature of 4 ±0.5℃ for 30 days was not detected.

Використання відпрацьованих глинистих сорбційних матеріалів у технологіях виробництва шкіри та хутра

The work is devoted to solving the current problem of increasing the level of environmental safety of treatment industrial wastewater of leather production from chromium ions (III) through the use of natural and modified bentonite. The most promising way of wastewater purification is the sorption technology, which is widely used in many countries to prevent pollution of the environment by wastewater from industrial enterprises. Studies of the use of natural and modified bentonite in the adsorption of Cr3 + ions have been carried out. The purpose of the research was to study the use of clay sorbents previously applied for the purification of wastewater from heavy metal ions in technological processes of leather and fur production. The possibility and modes of application of spent bentonite dispersions for the processing of leather semi-finished products to increase resource conservation and environmental friendliness of leather production were also established. The influence of the process duration on the sorption efficiency of chromium ions has been studied. Studies have been conducted to use spent bentonite in tanning and filling processes. The efficiency of modification of montmorillonite has been proved and the expediency of using mineral dispersion for qualitative formation of the structure and properties of the leather during tanning has been established.The efficiency of adsorption of anionic dyes on spent montmorillonite is investigated. Was identified a high level of adsorption of anionic dyes at pH 5-6.5. The role of the dye structure, the level of the critical concentration of micelle formation on the dye adsorption on the surface of montmorillonite is provided. Utilization of spent bentonite by using it as part of multifunctional materials for the processing of leather semi-finished products contributes to a considerable increase in resource conservation and environmental friendliness of leather production.

The Solution Properties of Polymethacrylate Molecular Brushes with Oligo(ethylene glycol) and Oligo(propylene glycol) Side Chains.

The properties of polymer brushes based on three macromonomers were investigated in aqueous and organic solutions. Methacrylic monomers with different compositions of the oligo(oxyalkylene) substituents and arrangements of the oligo(ethylene glycol) and oligo(propylene glycol) blocks were used for the synthesis of polymers. There were methoxy [oligo(ethylene glycol)10.3-block-oligo(propylene glycol)4.7] methacrylate, methoxy [oligo(propylene glycol)8.3-block-oligo(ethylene glycol)6.6] methacrylate, and methoxy oligo(propylene glycol)4.2 methacrylate. Molecular brushes were investigated by the methods of molecular hydrodynamics and optics in dilute solutions in acetonitrile, chloroform, and water. The peculiarities of behavior of poly[oligo(oxyalkylene) methacrylates] in aqueous solutions and water-toluene systems have been found; in particular, the solubility of the polymers in water and organic solvents, the polymers equilibrium distribution between the phases, and the surface activity in the water-toluene system have been established. The thermo-responsibility in aqueous solutions and values of a critical concentration of micelle formation were shown. Depending on the arrangement of blocks in the side chains of molecular brushes, they are characterized by different intramolecular density.

МЕМБРАННО-АССОЦИИРОВАННАЯ ТИАМИНКИНАЗА ИЗ ГОЛОВНОГО МОЗГА СВИНЬИ: РАСПРЕДЕЛЕНИЕ В СУБКЛЕТОЧНЫХ ФРАКЦИЯХ И ОТДЕЛАХ, АМИНОКИСЛОТНЫЙ СОСТАВ

Background. Thiamine kinase is a medical enzyme, genetically determined "breakdowns" during the synthesis of which lead to a number of neurodegenerative diseases. Knowledge of the distribution of the enzyme in the compartments of the brain, the regulatory capabilities of the globule in the formation of the coenzyme form of vitamin B1 – thiamine diphosphate, will enable to perform targeted correction of pathological conditions. Purpose of the study. To determine the localization of the enzyme in the pig's brain, the role of hydrophobic and hydrophilic interactions in association on membranes, the nature of amino acid residues that determine the structure of the protein. Material and methods. To obtain membranes, fresh brain, cleaned from membranes and vessels, filled with 4 volumes of chilled Tris-HCl buffer (50 mM, pH 7.4) with 0.2 mM EDTA and homogenized (2000 rpm–1) for 5 cycles. The homogenate was centrifuged for (60 min at 30,000 g), the supernatant was discarded into the membranes remaining in the pellet and subjected to solubilization with the initial buffer containing 0.05-1 % of detergents. The enzyme activity was assessed by the rate of thiamine diphosphate formation. Protein hydrolysis was carried out in evacuated ampoules with 6 M HCl at 110 °C for 18, 22, 48, and 72 h. The isoelectric point (pI) was calculated from the amino acid composition and using the isoelectric focusing method. The isoionic point, was determined by dialysis of thiamine kinase, followed by measuring the pH in the dialysate. Results. It was found that hydrophobic detergents have a more pronounced solubilizing effect compared to hydrophilic ones. At high values of the critical concentration of micelle formation (1 %), both of them change the conformational state of the macromolecule, affecting its affinity for substrates and effectors. Thiamine kinase is fairly evenly dispersed in all parts of the brain. However, the subcellular localization is different. Low enzymatic activity is observed in the mitochondrial fractions. The enzyme is characterized by an increased concentration of amino acids, contributing to the α-helicalization of the protein globule, while at the same time a low content of residues that bind polypeptide chains and high - carry out its sharp rotation by 130 °, incompatible with the course of the α-helix. Conclusions. Brain thiamine kinase is a membrane-associated protein. Hydrophobic forces are mainly involved in the interaction with the lipid bilayer of membranes. Depending on the concentration of the detergent, the solubilization process is accompanied by a change in the conformation of the globule. The main amount of thiamine kinase is concentrated in mitochondrial membranes.

Physical-chemical properties of FM-1 reagent as a potential collector for ion flotation of lanthanoids

The physical-chemical properties of the industrial reagent “FM-1” have been investigated. These properties are necessary for evaluating its use as a collector in the processes of concentration of rare earth metal ions by ion flotation. “FM-1”, which is based on sodium salts of aminomethylenephosphonic acids, is used as a flocculant for oil production and purification of process waters from suspended particles and petroleum products. Protolytic equilibriums in aqueous solutions of the reagents were studied. The values of dissociation constants equaling pKa1 = 2.31±0.26 and pKa2 = 8.82±0.34 were determined spectrophotometrically. Surface tension of the reagent solutions at the solution-air interface was studied. The “FM-1” reagent was classified as a strong surface-active substance with the following parameters: Minimal surface tension σmin = 29 mN∙m-1, surface activity G = 0.031 N∙m2∙mol-1, critical concentration of micelle formation 1∙10–3 mol∙L-1. The regularities of the reagent’s interaction with lanthanum (III) ions were studied. A high degree of lanthanum ions’ precipitation (over 99.7 %) was observed over a rather wide interval of pH values (4.00–12.00); at this point, at pH ≥ 7.5, lanthanum hydroxide can co-precipitate. The formation of compounds in a solution with molar ratios [La]:[FM-1] = 1:1 and 1:2 was established by conductometric titration method. The findings of chemical analysis, FTIR spectroscopy and elemental analysis of the isolated precipitates suggested their structural formula. A possibility for the “FM-1” reagent to be used as a collector for the ion flotation of lanthanum (III)ions was shown

Role of Counterions in the Adsorption and Micellization Behavior of 1:1 Ionic Surfactants at Fluid Interfaces─Demonstrated by the Standard Amphiphile System of Alkali Perfluoro-n-octanoates.

In our latest communication, we proved experimentally that the ionic surfactant’s surface excess is exclusively determined by the size of the hydrated counterion.[Lunkenheimer, Langmuir,2017, 33, 10216−1022410.1021/acs.langmuir.7b00786]28925711. However, at this stage of research, we were unable to decide whether this does only hold for the two or three lightest ions of lithium, sodium, and potassium, respectively. Alternatively, we could also consider the surface excess of the heavier hydrated alkali ions of potassium, rubidium, and cesium, having practically identical ion size, as being determined by the cross-sectional area of the related anionic extended chain residue. The latter assumption has represented state of art. Searching for reliable experimental results on the effect of the heavier counterions on the boundary layer, we have extended investigations to the amphiphiles’ solutions of concentrations above the critical concentration of micelle formation (cmc).We provided evidence that the super-micellar solutions’ equilibrium surface tension will remain constant provided the required conditions are followed. The related σcmc-value represents a parameter characteristic of the ionic surfactant’s adsorption and micellization behavior. Evaluating the amphiphile’s surface excess obtained from adsorption as a function of the related amphiphile’s σcmc-value enables you to calculate the radius of the hydrated counterion valid in sub- and super-micellar solution likewise. The σcmc-value is directly proportional to the counterion’s diameter concerned. Taking additionally into account the radii of naked ions known from crystal research, we succeeded in exactly discriminating the hydrated alkali ions’ size from each other. There is a distinct sequence of hydration radii in absolute scale following the inequality, Li+ > Na+ > K+ > (NH4)+ > Rb+ > Cs+. Therefore, we have to extend our model of counterion effectiveness put forward in our previous communication. It represents a general principle of the counterion effect.

SEPARATION OF WATER SYSTEMS CONTAINING SURFACTANTS

The possibility of highly efficient treatment of wastewater containing surfactants (surfactants) to a critical concentration of micelle formation by ultrafiltration (UV) by preliminary binding of surfactants into poly-complexes is shown. The effects of the parameters of the separation process and the conditions for the formation of a polycomplex on the UV efficiency indicators have been studied.

СИНТЕЗ И ИССЛЕДОВАНИЕ СВОЙСТВ НЕИОНОГЕННОГО ПОВЕРХНОСТНО-АКТИВНОГО ВЕЩЕСТВА НА ОСНОВЕ ЖИРНЫХ КИСЛОТ КУКУРУЗНОГО МАСЛА И ДИЭТАНОЛАМИНА

A new product has been obtained with the use of diethanolamine and corn oil fatty acids. The series of experiments have been performed to learn its composition, physico-chemical and colloid-chemical properties with the use of modern devices and methods. The results of IR-spectroscopy have approved the presence of specific functuonal groups: carboxilic, hydroxilic, and ester groups. The results of the experiments have shown that the synthesized substance posesses the surfactant properties and emulsifying ability, belongs to the group of high-dispersity and mono-dispersity systems. The particle size before reaching the critical point of micelle formation is 154.5 nm, at the CMC point - 294.7 nm, and after - 346.5 nm. Measuring the values of surface tension by the Du Nouy method allowed defining the critical concentration of micelle formation (0.25-0.5 g/dm3), at which the maximum wetting is achieved. It was shown that the contact angle of wetting of the water solution of a substance is less than 90° on a hydrophilic (gelatinous) surface. It was found that the synthesized diethanolamide is characterized by high resistance to aggregation, since the obtained values of the zeta potential below ± 10 mV were not observed. It was established that the synthesized product has an emulsifying ability in comparison with industrial oil. Besides, the highest stability of the emulsion is observed at a product concentration of 2.0 g/dm3. The developed substance belongs to non-ionic surfactants, the pH of the water solution is 6-7, it dissolves well in various organic solvents (toluene, hexane, xylene, dimethylformamide, acetone, white spirit, ethyl and isopropyl alcohols), and is slightly soluble in water. According to the calculations of the hydrophilic-lipophilic balance, it belongs to the oil-in-water emulsifiers.

SYNTHESIS AND PROPERTIES OF MODIFIED XANTHAN GUM

Xanthan gum is widely used as a stabilizing, emulsifying, thickening agent in pharmacology, medicine, food, oil, paint, textile, perfume, mining and agriculture. For food purposes, potassium, sodium or calcium salts of xanthan formed by carboxyl groups of glucuronic acid and pyruvate group are used. Currently, xanthan gum is not produced on an industrial scale in Russia. There are repeated attempts to create industries in various regions of the country.
 The paper synthesizes hydrophobized acetylated xanthan gum derivatives with different degrees of substitution. Physical-chemical and colloidal-chemical properties of initial and modified gum are compared by methods of viscosimetry, tensiometry, IR spectroscopy. The point of zero charge of xanthan gum is determined.. Change of macromolecule conformation depending on pH of aqueous solution and preliminary dewatering is shown. Delamination temperatures of initial and modified forms of xanthan gum were determined. The critical micelle formation concentration of the modified gum is 0.2%. At this concentration, the surface activity of the gum is 6.1 and 7.9 mJ m/kg when replacing two and five hydroxo groups, respectively. The possibility of using modified xanthan gum as a binder for obtaining fuel pellets with improved operational properties and calorific value is shown.

Анализ мицеллообразования и адсорбционных слоев бинарных смесей компонентов сульфатного мыла

Currently, the main trend of the pulp and paper industry development is bio-refining. It is based on integrated and deep processing of wood raw materials to obtain products with higher value added and reduced amount of waste. One of the high priority tasks of bio-refining is improvement of technology of by-product (sulphate soap) extraction from spent liquor with an increase in the yield and quality of the resulting product and a decrease in the level of environmental pollution. The complexity and energy intensity of sulphate soap extraction from spent liquor depends on many factors, including the species used for wood cooking, composition of extractives, the method of wood preparation for delignification, etc. Sulphate soap is a multicomponent emulsion with a predominant content of resin and fatty acids, small amount of unsaponifiable substances and an admixture of lignin, which is mainly extracted from waste liquior by settling. The low degree of its extraction is associated with the absence of systematical data on the mutual influence of the sulphate soap components. In this work, the patterns of intermolecular interaction of the individual components of the by-product (sulphate soap) are found. For this purposes the critical concentration of micelle formation (CCM) and surface tension depression of surface-active sodium oleate and sodium abietate and their mixtures of varying compositions were determined by the methods of tensiometry and conductometry. A detailed analysis of its mixed micelles and adsorption layers was carried out using the Rubin–Rosen pseudophase model. The interaction mechanisms of components in mixtures are explained. The impact on the composition of micelles and adsorption layers of the more surface-active sodium oleate was detected in mixed solutions. A maximum synergistic effect of micelle formation was observed in mixtures with a predominant content of sodium abietate. Analysis of experimental data and the result of sulphate soap modeling allow substantiating the complexity of its extraction from waste liquor after wood cooking with the presence of hardwood over 30 %, which is explained by the reduced content of resin acids in black liquor. For citation: Yakubova O.S., Demiantseva E.Yu., Smit R.A., Dubovy V.K. Analysis of Micelle Formation and Adsorption Layers of Binary Mixtures of Sulphate Soap Components. Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 6, pp. 196–205. DOI: 10.37482/0536-1036-2021-6-196-205

The Effect of Halide Counter Ions and Methanol on the Foaming Behavior of Cationic Surfactants and a Mechanism Study

Abstract In this work, four quaternary ammonium cationic surfactants including cetyltrimethyl ammonium fluoride (CTAF), cetyltrimethyl ammonium chloride (CTAC), cetyltrimethyl ammonium bromide (CTAB) and cetyltrimethyl ammonium iodide (CTAI) were investigated to study the effect of halide anions on the surface activity and foaming performance. The result showed that CTAF had superior surface activity, which could reduce the surface tension of water to 33.15 mN/m at a low CMC (critical micelle formation concentration) of 1.65 mmol/L. Based on the calculation of Amin (the minimum occupied area per surfactant molecule), we assumed that this higher surface activity was related to the small ionic radius of the fluorine ion (F–). The foamability and foam stability of CTAF has great advantages over other surfactants studied. On this basis, the factors affecting the formation and stabilization of the CTAF foam were investigated. The results showed that foam formation benefited from high temperatures and low methanol concentration, while high salinity was beneficial for foam stability. When CTAF at a concentration of 0.2% was used as a foaming agent, foaming was excellent at a methanol concentration of 10%, a salinity of 22 ⨯ 104 mg/L, and a temperature of 90°C. With this study, uncertainties that existed in the literature regarding the effect of anion on surface activity and foam performance were explained and the effect of temperature, methanol and salinity on foam generation and stabilization was understood.

Study of surface and rheological properties of clayless biopolymer drilling mud treated with M-1 surfactants

An important issue of improving the quality of the initial opening of the reservoir through the use of a system of drilling fluids treated with surfactant M-1. For high-quality disclosure, it is proposed to use clay-free biopolymer drilling mud. The main analyzed features of M-1 use as an additive to biopolymer drilling mud used in Ukrainian deposits. The formulation is substantiated and the study of clay-free biopolymer solution for primary opening of productive layers is carried out. Processed non-ionic surface active agent (surfactant) M-1 model biopolymer clayless drilling mud. With the use of oil (density 838 kg /m3) Kachanivsky oilfield conducted measuring the interfacial tension coefficient at the interface "mud filtrate – oil" stalagmometric metod by changes in the concentration range (% by weight) M-1 from 0 to 5. The influence of M-1 concentration on the interfacial tension coefficient at the interface of "oil – biopolymer drilling fluid filtrate" is shown and the critical concentration of micelle formation (CCM) of surfactant in the filtrate is found, the excess of which does not reduce the interfacial tension. It has been experimentally established that with increasing concentrations of M-1, the interfacial tension factor at the interface between the phases of "oil – filtrate of the drilling fluid" is sharply reduced, which leads to an increase in the formation fluid formation fluid. The rheological properties of drilling fluids with rotational viscometry are determined. Polynomial dependences of temperature influence on rheological properties without clay biopolymer drilling mud have been established.

Фізико-хімічні властивості та міцелоутворення розчинів полівінілового спирту різних молекулярних мас

The physicochemical properties (surface tension, dynamic viscosity, crystallization and melting temperatures) of polyvinyl alcohol solutions of molecular weight 9, 31 and 72 kDa have been studied. The surface tension and the critical concentration of micelle formation were determined by the method of stalogometry, and the dynamic viscosity was determined using an Oswald viscometer. The crystallization and melting temperatures were determined in a cooled modified chamber of the UOP-6 software freezer at a rate of 2°C/min. Cryomicroscopic studies were carried out on a polarizing microscope "MIN-8". The surface tension reflects the interaction of PVA solutions with the lipid layer of biomembranes and indicates the hydrophobic properties of substances. The viscosity of PVA solutions characterizes their interaction with water molecules and reflects hydrophilic interactions. The purpose of the study is to determine the physicochemical properties of PVS that characterize the hydrophilic-hydrophobic interactions in the studied solutions and the micelle formation of PVА solutions of different molecular weights. Materials and methods. Studies of the dynamic viscosity and density of 0.1%-1% PVA solutions of molecular weight 9, 31 kDa showed that these parameters increase with increasing PVA concentration, which leads to increased hydrophilicity of the solutions. Results and discussion. It was shown that the surface tension of PVA solutions decreases with increasing concentration, which leads to a decrease in the hydrophobic properties of the polymer. It was found that in 0.5% PVА solutions of molecular weight 9 and 31 kDa the crystallization and melting temperatures decrease from -5 to -6°C. At these temperatures, crystallization and melting of the solutions begin. Conclusion. The study of micelle formation in PVА solutions of different molecular masses was carried out, surface tension isotherms were constructed, and the break point on the isotherm corresponding to the CCM was determined. The values of the critical concentration of micelle formation of PVА of molecular masses 9, 31, 72 kDa were determined. Hydrophobic links of PVА of molecular masses 9 and 31 kDa form hydrophobic cavities in the micelle structure, which can reduce recrystallization activity

PECULARITIES OF MICELLE FORMATION OF PENTACYCLIC GLYCOSIDES IN AQUEOUS SOLUTIONS

The regularities of changes in structural characteristics during the formation of associates in micellar aqueous solutions of triterpene saponins Quillaja Saponin and Sapindus Mukorossi are considered. The dependence of surface tension and adsorption on the concentration of an aqueous saponin solution is analyzed, and the values of surface activity and parameters of the adsorption layer are calculated. The average values of diffusion coefficients for spherical and cylindrical micelles are determined based on the measurement of the solution viscosity. The effect of the electrolyte solution on the surface tension and viscosity of glycoside solutions is studied: when the electrolyte is introduced into the saponin solution, the surface tension decreases, which leads to a shift in the critical concentration of micelle formation towards lower concentrations. The introduction of potassium chloride electrolyte reduces the degree of ionization and, as a result of suppressing the electroviscosity effect, leads to a decrease in the viscosity of the solution. The dynamic light scattering method is used to determine the size of glycoside aggregates. It is established that there are aggregates of several sizes in an aqueous solution of saponin. The size and shape of aggregates were calculated using the concepts of micelle packing parameters. In the region of very low concentrations of glycoside solutions, when approaching the critical concentration of micelle formation in the solution, there are spherical micelles. A further increase in the saponin concentration in the solution leads to a decrease in the content of structures with a hydrodynamic radius of 50-80 nm and the appearance of larger agglomerates with sizes greater than 100 nm. It was found that micelles acquire a less hydrated and more densely packed cylindrical shape in the concentration range of 1.7-2.6 mmol/dm3. Compaction of associates leads to an increase in the content of particles with a hydrodynamic radius of 150-250 nm and larger ones, and their presence predicts the appearance of larger agglomerates. Analyzing the data obtained using the dynamic light scattering method, it can be concluded that aggregates of several sizes co-exist in the volume of aqueous saponin solutions at certain concentrations.

Research of surface-active properties and sizes of pectin molecules after post-alcohol grain distillery dreg

From the multicomponent composition of biologically active substances contained in wheat post-alcohol grain distillery dreg, the leading role in the manifestation of surface-active properties is presumably played by pectins. Therefore, the purpose of the work was to isolate pectins from the distillery dreg, study their surface-active properties and determine the size of molecules in the saturated adsorption layer to justify the possibility of using pectins in pharmaceutical practice as auxiliary substances. The physical and chemical characteristics of pectins isolated by the technology of complex processing of distillery dreg were studied: pH of 0.5% aqueous solution (4.25), average molar mass (1650•10-3 kg/mol), degree of polymerization (10), binding capacity to lead (II) ions (282.29 mg/g of pectin). According to a series of pectin solutions with a concentration of 0.5-6.1 mol/m3 the following parameters were determined and calculated experimentally at a temperature of 293 K: surface tension (51.96•10-3-67,55•10-3 N/m), surface activity (7.54), marginal surface excess (6.25•10-5 mol/m2), critical micelle formation concentration (1.48 mol/m3 or 0.24%). The found characteristics of the surface properties of the calculated size of the pectin molecule in a saturated adsorption layer: cross-sectional area (2,658 Å2), weight of pectin per unit area (1,031•10-4 kg/m2), the length of the molecule (1026 Å), the volume of the molecule (Å3 2727), the radius of the cross section of the molecule (0,920 Å), the cross-sectional diameter of the molecule (1,840 Å). The calculated size of the pectin molecule from distillery dreg in a saturated adsorption layer, comparable to the parameters of analogues (beet pectin, polygalacturonic acid, sodium alginate), indicate the biological availability of the tested pectins and creates the prospect of their pharmaceutical use in drug technology.

Preparation of a Gemini Surfactant from Mixed Fatty Acid and its Use in Cosmetics

Abstract Among the surfactants, dimeric surfactants represent a niche group with multifunctional properties. In this work a modified gemini surfactant was synthesized using symmetrical fatty acids. Due to the spacers used to combine the two symmetrical monomers, the synthesized gemini surfactant is cationic. The structure of the compound was confirmed with 1H-NMR. The most advantageous property of the gemini surfactant is that it has a lower surface tension, i. e. less than 35 mNm–1 at 25°C, compared to monomeric surfactants. The surface tension was determined with a Kyowa tensiometer. The CMC (critical micelle formation concentration) was calculated according to the pyrene method and detected by UV spectroscopy at 25°C. The very low CMC is another market advantage of the gemini surfactant. Hydrophobicity and hydrophilicity of the synthesized compound were checked by the emulsification method. The ability of the synthesized gemini surfactant to wet and foam and the emulsification index at different pH values were tested. Based on the results, the gemini surfactant was used in formulations for hair and skin care. Conditioners and creams were prepared with the synthesized compound and the properties were analyzed at different concentrations of the gemini surfactant in the respective formulation.

Study on the Interaction of Cationic Gemini Surfactant with Sodium Carboxymethyl Cellulose

Abstract In the present study, the interaction of the anionic polymer sodium carboxymethyl cellulose (NaCMC) with the two cationic gemini surfactant (C12-(EO)-E-C12 and C12-(EO)2-E-C12) has been investigated by surface tension and turbidity measurements. The co-adsorption of the polymer and the surfactants as well as the formation of highly surface-active polymer-surfactant complex was observed. By inserting the surface tension data into the Gibbs equation it could be shown that the surface layers of the mixed solutions have a multi-level adsorption structure. Comparing the critical adsorption concentration (C1), the critical saturation concentration (C2) and the critical micelle formation concentration (C3) of mixtures with different concentrations, it can be seen that all variables increase with the increase in polymer concentration. In addition, the inorganic salt (NaBr) greatly influences the C1, C2 and C3. The salt effects depend on the competition between the salt-enhancing effect and the salt-shielding effect.