Dynamic Surface Tension Values Research Articles

Exploring the Correlation of Dynamic Surface Tension with Antimicrobial Activities of Quaternary Ammonium-Based Disinfectants.

Quaternary ammonium compound (QAC) disinfectants represent one of our first lines of defense against pathogens. Their inhibitory and bactericidal activities are usually tested through minimum inhibitory concentration (MIC) and time-kill assays, but these assays can become cumbersome when screening many compounds. We investigated how the dynamic surface tension (DST) measurements of QACs correlate with these antimicrobial activities by testing a panel of potent and structurally varied QACs against the gram-positive Staphylococcus aureus and the gram-negative Pseudomonas aeruginosa. We found that DST values correlated well with bactericidal activity in real-world disinfection conditions but not with MIC values. Moreover, no correlation between these two antimicrobial activities of QACs (bactericidal and inhibition) was observed. In addition, we observed that the bactericidal activity of our QAC panel against the gram-negative P. aeruginosa was severely affected in the presence of hard water. Interestingly, we found that the counterion of the QAC affects the killing of bacteria in these conditions, a phenomenon not observed in most MIC assessments. Moreover, some of our best-in-class QACs show enhanced bactericidal activity when combined with a commercially available QAC. In conclusion, we determined that an intrinsic physical property of QACs (DST) can be used as a technique to screen for bactericidal activity of QACs in conditions that mimic real-world disinfection conditions.

A flow velocity dependence of dynamic surface tension in Plateau borders of foam

HypothesisLiquid drainage through foams is a multiscale process, that primarily occurs through channels known as Plateau borders (PBs). Recent experimental studies of isolated PBs have observed variations in channel surface tension, γ, with liquid flow rate, Q, for systems containing soluble low molecular weight surfactant (LMWS). The current study proposes that the dynamic surface tension (DST) could be responsible for this effect, where the residence time of surfactant molecules in the PB is similar to the time required for their adsorption to the channel interface. ExperimentsProfile geometries of isolated ‘ideal’ PB’s were created in a bespoke experimental setup at controlled forced liquid flow rates. Average surfactant residence times, τRes, were calculated for solutions of Sodium dodecylsulfate (SDS), Tween 20 (T20) and Tween 80 (T80), and used to calculate corresponding average DST values in discrete regions of measured PB profiles. DST values were combined with microscale drainage theory to assess the potential physical implications on liquid flow. FindingsSignificant variations in the magnitude of γ were calculated based on surfactant characteristics, where only the rapid adsorption of SDS was sufficient to produce DST values approaching equilibrium. These findings seriously question assumptions of near equilibrium surface tension in LMWS foam systems above their critical micelle concentration (CMC). Furthermore, the presence of surface tension gradients identified using this discrete approach, highlights the need to further refine the current theory to a continuous approach incorporating Marangoni effects.

Dynamic interfacial properties and foamability of polyelectrolyte-surfactant mixtures

Polymer/surfactant interaction and complexes can strongly influence foam formation and stability, however, a clear mechanism is still unknown and under investigation. Critical Aggregation Concentration (CAC) is introduced as an important parameter in recent investigations, however, CAC is mostly characterized as an equilibrium parameter, while foam formation and consequently the stability mechanism, is significantly influenced by the dynamics of adsorption. In this research the dynamic surface tension and viscoelasticity mixtures of Polystyrene Sulfonate (PSS) as an anionic polyelectrolyte and Cetyl Trimethyl Ammonium Bromide (CTAB) as a cationic surfactant, at the air-water interface are investigated by using Profile Analysis Tensiometry (PAT). The measured dynamic surface tension values illustrate three different regions of the surfactant/polymer ratio. It is demonstrated that a minimum number of surfactants per polymer molecule is needed in order that the polymer-surfactant complexes become sufficiently surface active and adsorb significantly at the water-air surface. For high surfactant concentrations, the large amounts of excess CTAB compete with polymer-surfactant complexes at the interfaces and remove the complexes into the bulk. The measured elasticity values confirm this observation. At intermediate surfactant concentration, when the complexes have their maximum surface activity, a fast dynamics of adsorption is observed and the measured elasticity values go through a maximum. The results of foam formation and stability also show a meaningful correlation with these results using Ross-Mill test and gas sparging method.

Adsorption equilibrium and dynamic surface tension of alkyl polyglucosides and their mixed surfactant systems with CTAB and SDS in the surface of aqueous solutions

The surface adsorption equilibrium and dynamic surface tension (DST) of alkyl polyglucosides (APGs) with single or mixed carbon chains (C8G1.46, C10G1.54, C12G1.46, C8/10G1.31 and C12/14G1.43), and of the mixed surfactant systems C8G1.46-CTAB and C8G1.46-SDS in aqueous solutions were studied. The magnitude in descending order for cmc and γcmc values of various APGs were C8G1 > C10G1 > C12G1 and C8/10G1.31 > C12/14G1.43. Both the APGs with single carbon chain and the APGs with mixed carbon chains, have approximately the same Γm and Amin values.When the concentration of APG is relatively small, the adsorption is controlled by diffusion. When APG concentrations increase, the adsorption mechanism changes from diffusion controlled into barrier controlled.The apparent diffusion coefficient (Da) decreases with an increase in APG concentrations. And the Da values of various APGs at the same concentration in descending order of magnitude is C8G1.46 > C10G1.54 > C12G1.46 and C8/10G1.31 > C12/14G1.43. The magnitude in descending order for the adsorption barrier values (Ea) of different APG products was C8G1.46 > C10G1.54 > C8/10G1.31 > C12/14G1.43 > C12G1.46. The longer the carbon chain of the APG molecules, the smaller the repulsive force of the APG molecules on the surface, and the faster the DST drops.In the C8G1.46-CTAB mixed system, when CTAB has relatively small concentration, adding C8G1.46 to CTAB solution will result in significantly lowered DST values. But when CTAB concentration is relatively large, adding C8G1.46 to CTAB solution will not result in significant change to the DST curves. The DST values of the C8G1.46-SDS mixed system is significantly lower than the single C8G1.46 and single SDS systems.

Colloid–chemical regression model in analyzing the relationship between dynamic surface tension and the content of total protein and albumins in blood

Mathematical statistics methods in chemistry and biology make it possible to apply certain analytical methods, e.g., interphase tensiometry, in diagnosing physiological states of humans and animals. This study is the first to use the regression method for modeling the relationship between the biochemical parameters of blood serum and dynamic surface tension (DST). We also demonstrate how the regression model can be used to determine the contents of total protein and albumins in blood serum from the known DST values at the liquid/air interface. As a result of constructing the regression model, we propose the regression equations characterizing the relationship between the DST values and the content of protein components in blood serum of animals.

Dynamic surface tension measurement for the screening of biosurfactants produced by Lactobacillus plantarum subsp. plantarum PTCC 1896.

Currently, screening of microbial biosurfactants (BSs) is based on their equilibrium surface tension values obtained using static surface tension measurement. However, a good surfactant should not only have a low equilibrium surface tension, but its dynamic surface tension (DST) should also decrease rapidly with time. In this study, screening of BSs produced by Lactobacillus plantarum subsp. plantarum PTCC 1896 (probiotic) was performed based on their DST values measured by Wilhelmy plate tensiometry. The relationship between DST and structural and functional properties (anti-adhesive activity) of the BSs was investigated. The results showed that the changes in the yield, productivity and structure of the BSs were growth medium and incubation time dependent (p<0.05). Structurally different BSs produced exhibited identical equilibrium surface tension values. However, differences among the structure/yield of the BSs were observed through the measurement of their DST. The considerable dependence of DST on the concentration and composition of the BS proteins was observed (p<0.05). Moreover, the anti-adhesive activity of the BS was found to be positively correlated with its DST. The results suggest that the DST measurement could serve as an efficient method for the clever screening of BSs producer/production condition, and consequently, for the investigation of probiotic features of bacteria, since the anti-adhesive activity is an important criterion of probiotics.

Comprehensive Analysis of the Colloid Biochemical Properties of Animal Milk as Complex Multicomponent System

The information about the major properties of animal milk is important in many aspects: from fundamental colloid problems till the nanotechnology and quality of milk production. The comprehensive analysis of the colloid biochemical properties of animal milk, including the study of the dynamic surface tension (DST) and the lipid-protein particles at micro- and nanoscale, has been proposed for such information set. The cow milk samples with almost equal fat and protein content (about 3.4%) are optimal by the main studied parameters: the maximal DST values, the maximal amount of fat globules with the diameters of 0.2–1.0 μm, minimal amounts of fat globules with all other diameters (1.0–10 μm), etc. The average diameters of the natural nanoparticles in the milk samples are increasing with the protein content increase, but not linearly. The particular rearrangements between all particles in milk take place by increasing fat-protein content. The obtained data underline the importance of the particular balance of the main milk fractions. We are describing the relationships of milk lipids and proteins, micro- and nanoscale structures, as well as the DST values that are useful also in some applied aspects (in food technology, product quality assessment, etc.).

Adsorption of nonionic Brij and Tween surfactants at PTFE-water and air-water interfaces: Investigations on wetting, dispersion stability, foaming and drug solubilization

Aqueous solutions of nonionic surfactants, namely Brij O10, Brij 35, Brij 98, Tween 20, Tween 60 and Tween 80 are investigated to understand their diffusion from the bulk solution to the surface and adsorption processes at PTFE-water interface using dynamic surface tension (DST), water penetration in packed PTFE powder and rate of sedimentation measurements. DST correlates well with the water penetration in packed PTFE powder (wettability) and the rate of sedimentation in aqueous dispersions for Brij surfactants. The results are described in terms of the structural features and HLB of respective surfactant and its ability to diffuse and adsorb at the interface. Brij O10 and Tween 60 showed maximum wettability and dispersion stability for respective series. We correlate the dynamic surface tension with interfacial phenomenon e.g. water penetration in the packed PTFE powder and the rate of sedimentation for aqueous dispersions. The diffusion towards air-water interface was essentially controlled by the molecular weight of the surfactant, while adsorption on the hydrophobic PTFE is controlled by the HLB of the respective surfactant molecule. We introduce a strategy to use PTFE particles as model for aqueous formulations involving hydrophobic drugs. The water penetration, wettability and stability of PTFE dispersions increase with lower DST values.

Interfacial tensiometry method for the analysis of model systems in comparison with blood as the most important biological liquid

Interfacial tensiometry of various liquids is an informative colloid-chemical method for the analysis of various liquids in many areas of natural sciences and medical practice. This method of dynamic surface tension (DST) measurements is proposed for the study of animal blood plasma or serum and mixtures of proteins, lipids, and salts as model systems. It is found that the saline affects lecithin aqueous dispersions significantly more weakly than those of the proteins. The DST values and biochemical parameters of the bovine blood serum of the same sample are obtained. Correlations between DST values and biochemical parameters of blood serum are found. They are both of fundamental and practical importance in laboratory diagnostics.

Laser beam resonant interaction of new hydantoin derivatives droplets for possible biomedical applications

This paper deals with the rapid molecular changes induced by laser radiation on two novel hydantoin derivatives, generically named SZ-2 and SZ-7, having promising pharmaceutical properties as Szymanska et al. in 2002 and Subtelna et al. in 2010 have reported. Hydantoins solutions with concentration of 10−3M in dimethyl sulfoxide were exposed both in droplets and bulk samples to coherent radiation emitted at 266nm as the fourth harmonic of a Nd:YAG laser during different time intervals. The influence of exposure to laser radiation was highlighted by laser induced fluorescence. Also, dynamic wetting (in terms of surface tension and contact angle) measurements were performed in order to find information valuable for further development and modification of hydantoins. All these studies intend to provide physical data in order to better understand the behavior and the activity of this kind of potential drugs on biological targets. Experimental results prove that the investigated molecules are photoreactive. Changes produced in a pendant microdroplet are orders of magnitude faster than in the case of bulk exposure.The surface tension values of unirradiated/irradiated hydantoin derivatives solutions in dimethyl sulfoxide are stable along the time interval of measurements, indicating that the molecules are evenly distributed in drop solution and they are not adsorbed at air–liquid interface. However, a very low gradient of dynamic surface tension values of the unirradiated samples, and the irradiated ones is registered for the SZ-2 compound. This suggests the modification of the cohesive strength of the molecules inside the droplets exposed to laser radiation.The contact angles equilibrium values of droplets on hydrophobic surface show no remarkable differences for unirradiated/irradiated imidazolidines samples, though the small increase of the contact angle for irradiated SZ-7 confers it a more hydrophobic property.

Protein-Silicone Oil Interactions: Comparative Effect of Nonionic Surfactants on the Interfacial Behavior of a Fusion Protein

To study the effect of three nonionic surfactants on the protein-silicone oil interactions. The adsorption of Tween® 80, Pluronic® F68 and Tween® 20 at the silicone oil/water interface (using shifts in frequency (ΔF) and resistance (ΔR) with quartz crystal microbalance) was compared to the adsorption at air/water interface (using surface tension). Effect of surfactants on protein adsorption to the silicone oil/water interface was studied in sequential- and co-adsorption modes. Protein-surfactant binding in the bulk was measured using dynamic surface tension method. Saturation of air/water and silicone oil/water interfaces by surfactants was observed at similar bulk concentrations. ΔF due to protein adsorption to the interface decreased only when surfactant was present as a pre-adsorbed species. Insignificant differences in the dynamic surface tension values of surfactant solutions were observed in the presence of protein. Similar hydrophobic forces were responsible for driving the surfactant adsorption at both air/water and silicone oil/water interfaces. Surfactants were effective in reducing the protein adsorption to the silicone oil only when introduced before or along with the protein. No significant binding between the protein and surfactants was observed in the bulk.

Investigation of dynamic surface tension of biological liquids for animal blood diagnostics

Dynamic surface tension (DST) methodology was successfully applied to the measurements of the animal blood plasma and serum. The DST values and their correlations with the most important biochemical parameters of horse blood were obtained for the first time. A numerous strong correlations were found in the case of mares (female), whereas only middle or weak – for stallions (male). The influence of horse ages on the DST values and biochemical parameters of their blood was found. An importance of DST application as express-method for animal blood diagnostics was proved.

Interfacial Behavior of N-Nitrosodiethylamine/Bovine Serum Albumin Complexes at the Air−Water and the Chloroform−Water Interfaces by Axisymmetric Drop Tensiometry

Interfacial properties of N-nitrosodiethylamine/bovine serum albumin (NDA/BSA) complexes were investigated at the air-water interface. The interfacial behavior at the chloroform-water interface of the interaction product of phospholipid 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), dissolved in the chloroform phase, and NDA/BSA complex, in the aqueous phase, were also analyzed by using a drop tensiometer. The secondary structure changes of BSA with different NDA concentrations were monitored by circular dichroism spectroscopy at different pH and the NDA/BSA interaction was probed by fluorescence spectroscopy. Different NDA/BSA mixtures were prepared from 0, 7.5 x 10(-5), 2.2 x 10(-4), 3.7 x 10(-4), 5 x 10(-4), 1.6 x 10(-3), and 3.1 x 10(-3) M NDA solutions in order to afford 0, 300/1, 900/1, 1 500/1, 2 000/1, 6 000/1, and 12 500/1 NDA/BSA molar ratios, respectively, in the aqueous solutions. Increments of BSA alpha-helix contents were obtained up to the 2 000/1 NDA/BSA molar ratio, but at ratios beyond this value, the alpha-helix content practically disappeared. These BSA structure changes produced an increment of the surface pressure at the air-water interface, as the alpha-helix content increased with the concentration of NDA. On the contrary, when alpha-helix content decreased, the surface pressure also appeared lower than the one obtained with pure BSA solutions. The interaction of DPPC with NDA/BSA molecules at the chloroform-water interface produced also a small, but measurable, pressure increment with the addition of NDA molecules. Dynamic light scattering measurements of the molecular sizes of NDA/BSA complex at pH 4.6, 7.1, and 8.4 indicated that the size of extended BSA molecules at pH 4.6 increased in a greater proportion with the increment in NDA concentration than at the other studied pH values. Diffusion coefficients calculated from dynamic surface tension values, using a short-term solution of the general adsorption model of Ward and Tordai, also showed differences with pH and the NDA concentration. Both, the storage and loss dilatational elastic modulus were obtained at the air-water and at the chloroform-water interfaces. The interaction of NDA/BSA with DPPC at the chloroform-water produced a less rigid monolayer than the one obtained with pure DPPC (1 x 10(-5) M), indicating a significant penetration of NDA/BSA molecules at the interface. At short times and pH 4.6, the values of the storage elastic modulus were larger and more sensible to the NDA addition than the ones at pH 7.1 and 8.4, probably due to a gel-like network formation at the air-water interface.

Surface properties of mixed monolayers of sulfobetaines and ionic surfactants

To study the influence of the head group in the properties of the mixed monolayers adsorbed at the air–water interface, the surface tension and surface potential of binary mixtures of surfactant have been determined as a function of the surfactant composition. Experiments were carried out with anionic–zwitterionic sodium dodecyl sulfate and dodecyl dimethyl ammoniopropane sulfonate (SDS/DDPS), and cationic–zwitterionic dodecyl trimethylammonium bromide and dodecyl dimethyl ammoniopropane sulfonate (DTAB/DDPS), and dodecyl trimethylammonium bromide and tetradecyl dimethyl ammoniopropane sulfonate (DTAB/TDPS). It was shown that mixed monolayers of cationic–zwitterionic surfactant exhibit small negative deviations of ideal behavior, whereas for SDS/DDPS monolayers show strong negative deviation from the ideality. Deviations of ideal behavior are interpreted by regular solution theory. The surface potential values agree very well with the concentration of the ionic component at the interface. The dynamic surface tension values show that the adsorption kinetics on the interface is a diffusion-controlled process. In monolayers with significant deviation of the ideal behavior, anionic–zwitterionic, there is some evidence of intermolecular attractions after diffusion of both surfactants at the interface.

Interfacial properties and structural conformation of thermosonicated bovine serum albumin

Aqueous Bovine Serum Albumin (BSA) solutions were treated with high-intensity ultrasound (20 W cm−2) for 15, 30 and 45 min at temperatures of up to 85 °C. The equilibrium and dynamic surface tension of native and ultrasonicated BSA at the air-solution interface was measured using drop shape analysis. The effect of ultrasound on the secondary structure of BSA was monitored by circular dichroism spectroscopy. Surface pressure of BSA at the air-solvent interface increased as a consequence of sonication treatment at 20 °C. Both the rate of surface pressure increase and the equilibrium surface pressure of sonicated BSA were significantly different than that of native BSA. Diffusion coefficients calculated from dynamic surface tension values using long-term and short-term solutions of the general adsorption model of Ward and Tordai increased upon application of ultrasound, e.g. Deff,shortterm≈5.2×10−9 m2/s for native BSA and Deff,shortterm≈2×10−8 m2/s for BSA solutions sonicated for 45 min. Deconvolution of circular dichroism spectra indicated a small but reproducible increase in helical content and a 22% decrease in unordered structure elements after 45 min of sonication. The increase in the rate of protein adsorption with ultrasonication was more pronounced at elevated temperatures. Above the denaturation temperature of the protein, both heat treatment and thermosonication were found to reduce helical content of BSA, e.g. from 61% for native protein to 31 and 40% for heat-treated and thermosonicated proteins at 85 °C, respectively. Results were attributed to an ultrasonically-induced modification of the molecular structure of BSA with increased intramolecular mobility and surface activity.

Effect of Sodium Halide on Dynamic Surface Tension of a Cationic Surfactant

AbstractThe equilibrium and dynamic surface tension (DST) of the novel cationic surfactant, 3‐(p‐nonylphenoxy)‐2‐hydroxylpropyl trimethyl ammonium bromide, abbreviated as RTAB, were studied. The effect of sodium halide such as NaCl, NaBr and NaI on the DST behavior of the RTAB solution below its CMC was studied in detail. Due to the preferential adsorption, the effect of hydration and salting out, the ability to reduce the DST values at the same concentration was in the order of NaI&gt;NaBr&gt;NaCl. Attributed to its high surface activity, the equilibrium time of the DST of the surfactant solution was insensitive to the ionic strength.

The influence of penetration enhancers on the volume instilled of eye drops

The influence of the physicochemical properties of various penetration enhancers on the weight of drops dispensed from flexible plastic dropper bottles was examined. Two dropper tips with a different design were compared and the dropper bottle was held in the upright position (90° angle) or at a 45° angle. These two angles were chosen to simulate the manipulation of an eye dropper bottle by the patient. The surface tension of the penetration enhancer solutions was determined using the dynamic drop volume method. The dynamic surface tension values ranged from 65 to 30 mN/m. The lower the surface tension of the solution, the lower the weight of the drop delivered. Both the design of the dropper tip and the manipulation technique of the dropper bottle had a moderate to important influence on the drop weight. The relationship between the surface tension of the penetration enhancer solution instilled and the comfort of the patient was evaluated by an acceptability test based on answering a questionnaire. Penetration enhancers can be used to reduce the drop size of conventional ophthalmic solutions on condition that they do not elicit local irritation.

Interfacial properties of cell culture media with cell‐protecting additives

In an effort to identify key rheological properties that contribute to cell protection against shear damage, we have measured surface shear and dilatationai viscosities, dynamic surface tension, foaminess, and foam stability for media containing cell-protecting additives. In a companion article,(18) we found that cell-to-bubble attachment was decreased in media containing Methocel, Pluronic F68, or polyvinyl alcohol (PVA). In medium containing polyethylene glycol (PEG) or potyvinyl-pyrrolidone (PVP), attachment was increased. PEG, PVP, serum (FBS), and serum albumin (BSA) increased the surface viscosity of the air/medium surface (thus, producing a more rigid interface), whereas F68 and PVA lowered it greatly. Foaming experiments showed that Methocel, PEG, PVA, and F68 decreased the foam half-life while FBS, BSA, and PVP were foam stabilizers. Interestingly, the foam stability of CHO cell suspensions decreased significantly for cell concentrations higher than ca. 2 x 10(6) cells/mL. Nonviable CHO cells reduced foam stability further. Dynamic surface tension values of the media tested were found significantly differentfrom their static surface tension values. The interfacial properties measured and the results presented in the companion study suggest that the additives that lower dynamic surface tension the most (Methocel, F68, and PVA) correlate well with reduced cell-to-bubble attachment, and thus, cell protection. Reduced dynamic surface tension with these additives implies faster surfactant adsorption, mobile interfaces, lower surface viscosity, and foam destabilization. Because PEG and PVP resulted in increased cell-to-bubble attachment and had different interfacial properties, a different mechanism (compared with Methocel, PVP, and F68) is apparently responsible for their protective effect. Finally, cell protection offered by FBS and BSA is attributed to the foam stabilization properties provided by these additives. (c) 1995 John Wiley & Sons Inc.

Dynamic surface tension of coal-water slurry fuels

Experiments were conducted to measure the dynamic surface tension of coal-water slurry (CWS) mixtures containing various types of surfactants and with different coal loadings. A maximum air bubble pressure technique measured the dynamic surface tension. The coal used for the CWS had 55 μm volume mean diameter (VMD) and was mined from the Upper Elkhorn seam, Virginia. Five surfactants were selected for the study: one non-ionic alkylphenol ethoxylate (NP-100), and four anionic surfactants; branched dodecylbenzene sulfonic acid (DDBS-hard), linear dodecylbenzene sulfonic acid (DDBS-soft), a sodium salt of a branched alkylbenzene sulfonic acid (1223H), and a sodium salt of sulfonated fatty acid (1840X). To determine the critical micelle concentration (CMC), the static surface tension was also measured using a du Nouy ring tensiometer. Measured values of dynamic surface tension are presented for 40 and 50% CWS mixtures, with surfactant concentrations ranging from 0.1 to 5.0% in weight.

The analysis of dynamic surface tension of sodium alkyl sulphate solutions, based on asymptotic equations of adsorption kinetic theory

We analysed existing and newly derived asymptotic solutions of the adsorption kinetic equations for the liquid phase interface in the regions of infinitely small and infinitely great surface lifetimes ( t) for the cases of one and of a few surfactants, on non-deforming and deforming surfaces, under non-stationary, stationary and quasi-stationary conditions, assuming either the diffusion adsorption mechanism or mixed adsorption mechanism. It was proved that in the region t → ∞, the adsorption barrier does not influence the dynamic surface tension σ, but the role of surface-active contaminants is significant. In contrast, in the region t → 0, the role of contaminants is small, but the adsorption barrier influences the dynamic surface tension substantially. The dynamic surface tension of sodium alkyl sulphate solutions was measured by the maximum bubble pressure method, in the t range 0.001–10 s. In the region t → ∞ we obtained good agreement of experimental results with asymptotic formulae. The diffusion adsorption mechanism of the surfactant solutions studied was confirmed and we also estimated the concentration values of the surfactant admixtures. Small additions of the more active surfactant sodium tetradecyl sulphate to sodium dodecyl sulphate substantially influences the shape of the σ— t curve in the region t → ∞, increasing (in full accordance with theoretical considerations) the tangent value of the curve inclination of the dependence of σ on t −1/2. In the regions t → 0, long-chained high molecular weight sodium alkyl sulphates adsorb according to the diffusion mechanism, whereas for sodium decyl and dodecyl sulphates the existence of the adsorption barrier was confirmed. We corroborated experimentally the absence of any influence of surfactant admixtures on the values of dynamic surface tension at t → 0.