Range Of Surface Pressures Research Articles

Effects of Charge Density on Spread Hyperbranched Polyelectrolyte/Surfactant Films at the Air/Water Interface.

The interfacial structure and morphology of films spread from hyperbranched polyethylene imine/sodium dodecyl sulfate (PEI/SDS) aggregates at the air/water interface have been resolved for the first time with respect to polyelectrolyte charged density. A recently developed method to form efficient films from the dissociation of aggregates using a minimal quantity of materials is exploited as a step forward in enhancing understanding of the film properties with a view to their future use in technological applications. Interfacial techniques that resolve different time and length scales, namely, ellipsometry, Brewster angle microscopy, and neutron reflectometry, are used. Extended structures of both components are formed under a monolayer of the surfactant with bound polyelectrolytes upon film compression on subphases adjusted to pH 4 or 10, corresponding to high and low charge density of the polyelectrolyte, respectively. A rigid film is related to compact conformation of the PEI in the interfacial structure at pH 4, while it is observed that aggregates remain embedded in mobile films at pH 10. The ability to compact surfactants in the monolayer to the same extent as its maximum coverage in the absence of polyelectrolyte is distinct from the behavior observed for spread films involving linear polyelectrolytes, and intriguingly evidence points to the formation of extended structures over the full range of surface pressures. We conclude that the molecular architecture and charge density can be important parameters in controlling the structures and properties of spread polyelectrolyte/surfactant films, which holds relevance to a range of applications, such as those where PEI is used, including CO2 capture, electronic devices, and gene transfection.

Surface Properties of Aqueous Dispersions of Bovine Serum Albumin Fibrils

The surface properties of aqueous dispersions of worm-like fibril aggregates of bovine serum albumin (BSA) differ from those of the adsorption layers of the native protein. The dispersions of BSA fibrils are characterized by slower changes of the surface tension and dynamic surface elasticity and also have different steady-state values of the surface properties. The fourfold compression of the adsorption layer of BSA fibrils leads to noticeably higher surface pressures than those of a compressed layer of the native protein, indicating the formation of a more rigid layer structure in the former case. The spreading of BSA fibrils onto a liquid surface from a concentrated dispersion reduces the effect of surface-active admixtures on the layer properties. The dependencies of the dynamic surface elasticity on surface pressure almost coincide for the spread layers of fibrils and the native protein in the range of low surface pressures, but only the spreading of the native protein can lead to surface pressures higher than 4 mN/m. This distinction is presumably caused by the formation of stable clusters of BSA fibrils at the interface and their slow propagation along the liquid surface.

High-performance tribo-components through combination of materials on the macroscale

The tribological performance of four different tribocomposite assemblies was comparatively investigated by sliding against a steel ring on a block-on-ring tribometer in a wide range of surface pressure (p) and sliding velocity (v), and the experimental results were described by a model. The results show that the friction coefficient in the stationary friction phase and the specific wear rate of the composite assemblies tend to follow the superior partner. Surprisingly, it is also found that the pv-load limit can be shifted to the higher pv-limit of the better partner. The results of the present work clearly show that the macroscopic combination of tribocomposites can be an excellent approach for the fabrication of tribological components, e.g. bearings, with long lifetime, high energy and eco-efficiency.

惑星大気のためのラインバイラインおよび相関 <i>k</i> 分布放射モデルの開発

A set of line-by-line and correlated k-distribution radiation models are developed aiming for applications in simulations and examinations of Venus and Mars-like planetary atmospheres. Our line-by-line model is validated by comparing the results with observations and those of previous studies under conditions of Venus, and present and possible early Mars. The radiation fields calculated by our line-by-line model agree well with observed profiles and are within the acceptable range from those presented in previous studies. The results obtained by our line-by-line model are then processed to generate a series of parameters for our correlated k-distribution model. It is confirmed that the radiation fields calculated with those sets of parameters by our correlated k-distribution model sufficiently agree with those by our line-by-line model for the atmospheres with a wide range of surface pressure. By the use of our correlated k-distribution model implemented with those sets of parameters, we evaluate the radiation field for Venus and calculate radiative-convective equilibrium profiles for Venus and Mars. The obtained vertical thermal structures for Venus are qualitatively consistent with observations, and the behaviors of surface pressure and surface temperature for Mars are similar to those reported by previous studies. Those results demonstrate that our models including the procedure for generating tables of radiation parameters are applicable to examine climates of CO2 dominant atmospheres in our solar and exoplanetary systems.

The Biomimetic System of Oleanolic Acid and Oleic Acid at the Air-Water Interface-Interactions in Terms of Nanotechnology-Based Drug Delivery Systems.

Oleanolic acid (OLA) and oleic acid (OA) are ubiquitous in the plant kingdom, exhibiting a therapeutic effect on human health, and are components of novel pharmaceutical formulations. Since OLA has limited solubility, the utilization of nanotechnology-based drug delivery systems enhancing bioavailability is highly advantageous. We report on the interfacial behavior of the OLA:OA system at various molar ratios, using the Langmuir technique to assess the dependence of the molar composition on miscibility and rheological properties affecting film stability. Specifically, we evaluate the interfacial properties (morphology, thermodynamics, miscibility, and viscoelasticity) of the OLA:OA binary system in various molar ratios, and indicate how the OLA:OA system exhibits the most favorable molecular interactions. We apply the Langmuir monolayer technique along with the complementary techniques of Brewster angle microscopy, dilatational interfacial rheology, and excess free energy calculations. Results demonstrate that the properties of mixed monolayers depend on OLA:OA molar ratio. Most of the systems (OLA:OA 2:1, 1:1, 1:5) are assumed to be immiscible at surface pressures >10 mN/m. Moreover, the OLA:OA 1:2 is immiscible over the entire surface pressure range. However, the existence of miscibility between molecules of OLA and OA in the 5:1 for every surface pressure tested suggests that OA molecules incorporate into the OLA lattice structure, improving the stability of the mixed film. The results are discussed in terms of providing physicochemical insights into the behavior of the OLA:OA systems at the interface, which is of high interest in pharmaceutical design.

Nanomechanical and structural study of Au38 nanocluster Langmuir-Blodgett films using bimodal atomic force microscopy and X-ray reflectivity

HypothesisLangmuir-Blodgett (LB) technique allows the deposition of gold nanoparticles and nanoclusters (atomically precise nanoparticles below 2 nm in diameter) onto solid substrates with an unprecedented degree of control and high transfer ratios. Nanoclusters are expected to follow the crinkle folding mechanism, which promotes the formation of trilayers of nanoparticles but kinetically disfavors the formation of the fourth layer. ExperimentsLB films of Au38(SC2H4Ph)24 nanocluster were prepared at a range of surface pressures in the bilayer/trilayer regime and their internal structure was analyzed with X-ray Reflectivity (XRR) and Grazing-Incidence Wide-Angle X-ray Scattering (GIWAXS). Bimodal atomic force microscopy (AFM) imaging was used to quantify the elastic modulus, which can be correlated with the topography at the same point on the surface. FindingsNanocluster bilayers and trilayers exhibited the elastic moduli of ca. 1.2 GPa and 0.9 GPa respectively. Films transferred in the 20–25 mN/m surface pressure regime displayed a particular propensity to form highly vertically organized trilayers. Further compression resulted in disorganization of the layers. Crucially, the use of two cantilevers of contrasting stiffness for bimodal AFM measurements has demonstrated a new approach to quantify the mechanical properties of ultrathin films without the use of deconvolution algorithms to remove the substrate contribution.

Possible Dependence of Climate on Atmospheric Mass: A Convection–Circulation–Cloud Coupled Feedback

AbstractThe total mass of the atmosphere [or equivalently, the background surface pressure (SP)] may have varied significantly over the evolutionary histories of Earth and other planets. Atmospheric mass can affect climate by modifying physical processes, including shortwave scattering, the emissivity of greenhouse gases, the atmospheric heat capacity, and surface fluxes. We apply a three-dimensional global climate model to explore the dependence of climate on SP over the range of 0.5–2.5 bar. Our simulations show an intriguing, nonmonotonic dependence of climate on SP. Over the SP range of 0.5–0.9 and 1.5–2.5 bar, the surface temperature increases with SP; however, over the SP range of 0.9–1.5 bar, the surface temperature decreases with SP. The negative correlation is due to a convection–circulation–cloud coupled feedback. As SP increases, the moist adiabatic lapse rate increases, leading to upper-troposphere cold anomalies in the tropics and middle latitudes that increase the midlatitude baroclinicity and eddy activity. In association with these changes, the eddy-driven jet is strengthened and shifts equatorward, and two separate westerly jets merge into a single jet. These abrupt circulation changes result in an equatorward shift of the midlatitude cloud belt and reduction of polar clouds, which induce strong negative cloud radiative forcing that cools the climate. Our results demonstrate that the regime transition of flow state (e.g., the merge of jets here) may induce large anomalies in clouds and radiative forcing, resulting in nonlinear climate responses.

Can volcanism build hydrogen-rich early atmospheres?

Hydrogen in rocky planet atmospheres has been invoked in arguments for extending the habitable zone via N2-H2 and CO2-H2 greenhouse warming, and providing atmospheric conditions suitable for efficient production of prebiotic molecules. On Earth and Super-Earth-sized bodies, where hydrogen-rich primordial envelopes are quickly lost to space, volcanic outgassing can act as a hydrogen source, provided it balances the hydrogen loss rate from the top of the atmosphere. Here, we show that both Earth-like and Mars-like planets can sustain atmospheric H2 fractions of several percent across relevant magmatic fO2 ranges. In general this requires hydrogen escape to operate somewhat less efficiently than the diffusion limit. We use a thermodynamical model of magma degassing to determine which combinations of magma oxidation, volcanic flux and hydrogen escape efficiency can build up appreciable levels of hydrogen in a planet's secondary atmosphere. On a planet similar to the Archean Earth and with a similar magmatic fO2, we suggest that the mixing ratio of atmospheric H2 could have been in the range 0.2-3%, from a parameter sweep over a variety of plausible surface pressures, volcanic fluxes, and H2 escape rates. A planet erupting magmas around the Iron-Wüstite (IW) buffer (i.e., ∼3 log fO2 units lower than the inferred Archean mantle fO2), but with otherwise similar volcanic fluxes and H2 loss rates to early Earth, could sustain an atmosphere with approximately 10-20% H2. For an early Mars-like planet with magmas around IW, but a lower range of surface pressures and volcanic fluxes compared to Earth, an atmospheric H2 mixing ratio of ∼2-8% is possible. On early Mars, this H2 mixing ratio could be sufficient to deglaciate the planet. However, the sensitivity of these results to primary magmatic water contents and volcanic fluxes show the need for improved constraints on the crustal recycling efficiency and mantle water contents of early Mars.

High-resolution reflection spectra for Proxima b and Trappist-1e models for ELT observations

ABSTRACT The closest stars that harbor potentially habitable planets are cool M-stars. Upcoming ground- and space-based telescopes will be able to search the atmosphere of such planets for a range of chemicals. To facilitate this search and to inform upcoming observations, we model the high-resolution reflection spectra of two of the closest potentially habitable exoplanets for a range of terrestrial atmospheres and surface pressures for active and inactive phases of their host stars for both oxic and anoxic conditions: Proxima b, the closest potentially habitable exoplanet, and Trappist-1e, one of 3 Earth-size planets orbiting in the Habitable Zone of Trappist-1. We find that atmospheric spectral features, including biosignatures like O2 in combination with a reduced gas like CH4 for oxic atmospheres, as well as climate indicators like CO2 and H2O for all atmospheres, show absorption features in the spectra of Proxima b and Trappist-1e models. However for some features like oxygen, high-resolution observations will be critical to identify them in a planet's reflected flux. Thus these two planets will be among the best targets for upcoming observations of potential Earth-like planets in reflected light with planned Extremely Large Telescopes.

Influence of temperature on dynamic surface properties of spread DPPC monolayers in a broad range of surface pressures

This work is focused on the study of the dynamic surface properties of spread monolayers of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), which is the main component of the pulmonary surfactant (PS), in the region of high surface pressures and at different temperatures. The increase of temperature from 25 to 35 °C led to a decrease of surface elasticity in the high surface pressure range corresponding to physiological conditions inside alveoli during breathing. Furthermore, the obtained results evidenced that the relaxation processes in spread DPPC monolayer were accelerated with the increase of temperature, which resulted in two different effects. On one hand, it led to the increase of hysteresis of surface pressure isotherms, which was an important condition for maximizing air penetration into alveoli; whereas on the other hand, it prevented reaching extremely high surface pressure, which could result in a premature alveolar collapse.

Dynamic properties and relaxation processes in surface layer of pulmonary surfactant solutions

In this work, dynamic surface properties of spread monolayers of DPPC and adsorbed layers of PS solutions were investigated in a broad range of surface pressure. Application of a modified Langmuir trough and a recently developed approach for the analysis of a non-linear response of the adsorption layer to large surface deformations gives a possibility to determine the dilational surface elasticity in the region of high surface pressures corresponding to the physiological state of the lung alveoli surface. Although DPPC is the main component of the complex pulmonary surfactant (PS) mixture, the dynamic surface properties of the adsorption layers of these two compounds are different. Other components in the PS adsorption layer lead to a decrease of the dynamic surface elasticity due to a looser packing of the layer, as confirmed by ellipsometry and infrared reflection absorption spectroscopy. Moreover, in the region of high surface pressures the main relaxation time of the surface stresses is much lower than that for spread DPPC monolayers. The fast relaxation in the adsorption layer can be connected with the redistribution of molecules between the surface and the subsurface layer in the course of compression. The acceleration of the relaxation processes can lead to a decrease of the number and size of collapsed parts of the layer and thereby to a decrease of the number of molecules with lost functional properties. This effect can be one of the reasons for the lower efficiency of synthetic pharmaceutical drugs, which do not have proteins in their composition, as compared with the natural PS extracted from animal lungs.

On the relationship between surface pressure, terrain elevation, and air temperature. Part I: The large diurnal surface pressure range at Gale Crater, Mars and its origin due to lateral hydrostatic adjustment

The daily variation of surface pressure observed by the Curiosity Rover Environmental Monitoring Station (REMS) is both significantly larger than observed at other landing sites on Mars and larger than simulated for the Curiosity site by global circulation models (GCM). Mesoscale numerical models are able to simulate the large REMS daily pressure range, but only if they possess sufficiently high horizontal resolution (grid spacing <5 km); low resolution (120–500 km) GCM simulations typically generate daily ranges of about half the observed value. The pressure range in low resolution simulations corresponds to the large-scale thermal tides and the augmentation of this range in high resolution models is associable with mesoscale topographic and surface property variations in the Gale Crater region. We show that the augmentation is due to the lateral redistribution of mass required for the surface pressure distribution over topographic relief to remain approximately hydrostatic as the near-surface air temperature varies through the diurnal cycle. The physical origin and nature of this adjustment flow is explored. We provide a means of predicting the daily surface pressure due to lateral hydrostatic adjustment for any location and further show that this range is slightly reduced by the inability of the atmosphere to completely achieve hydrostaticity and by the thermal effects of induced flows.

Dilational surface elasticity of spread monolayers of pulmonary lipids in a broad range of surface pressure

A new approach to the analysis of nonlinear surface dilational rheological properties was developed with the aim to enlarge the accessible range of surface pressures. The dilational surface elasticity of spread monolayers of DPPC, cholesterol, DMEA and their mixtures was determined in the region of low surface tensions (less than 10 mN/m) corresponding to the state of pulmonary surfactants at the lung interface. The dilational surface elasticity of pure DPPC monolayer proved to be high (∼200 mN/m) up to the collapse. The addition of cholesterol, DMEA or their mixture to the DPPC monolayer increased the dynamic surface elasticity, but could decrease significantly the surface pressure of the monolayer collapse if the concentration of additions exceeds an optimal value.

Assessment of various turbulence models (ELES, SAS, URANS and RANS) for predicting the aerodynamics of freight train container wagons

This study presents an assessment of the capabilities of various turbulence modelling approaches —ELES, SAS, URANS and RANS—to predict the aerodynamic flow around a double-stacked freight wagon, both in isolation and within a train. The numerical predictions are compared with experimental measurements at the same Reynolds number to determine the accuracy of each model. Specifically, aerodynamic drag, front and rear surface pressures, planar velocity fields and skin friction lines are validated against the wind tunnel results. In particular, predictions from the ELES and SAS models show good agreement with the wind tunnel data, both qualitatively and quantitatively. Indeed, ELES predicts both the range and distribution of the rear-face surface pressure very closely, indicating that the separated flow is also likely to be well predicted. Both SAS and ELES predict the pressure drag of the multi-wagon configuration to within 2% of the experimental value. However, the steady RANS model predicts the trends in pressure drag in line with the experiments as the front and rear gaps are varied, even though individual drag predictions are considerably worse. Overall, the set of results establishes the benefits and deficiencies of using particular turbulence models to capture different aspects of freight train aerodynamics.

Cavity Orientation Regulated by Mixture Composition and Clustering of Amphiphilic Cyclodextrins in Phospholipid Monolayers.

Artificial supramolecular-hierarchical structures that emulate nature represent an overcoming alternative for the design of new drug delivery systems. Thermodynamic and topographic properties of films formed by a monoacylated amphiphilic β-cyclodextrin (βCD-C16) with the phospholipid 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) at the air/water interface were studied. βCD-C16 formed stable mixed films with POPC at several proportions when spread together at the air/water interface. The orientation of βCD-C16 cavity at the interface depends on its mole fraction in the film as reveled by the analysis of partial mean molecular areas as a function of composition. Furthermore, βCD-C16 was able to penetrate POPC preformed films in a broad range of initial surface pressures, including that near the collapse pressure of the phospholipid. These results demonstrated the strong tendency of βCD-C16 to be inserted into this lipid matrix commonly used in liposome formulations. Topography studies show that βCD-C16 segregate from POPC forming clusters enriched in βCD-C16. Segregation of βCD-C16 was especially noticeable when βCD-C16 were incorporated by themselves into a preformed POPC matrix leading to ordered and highly birefringent structures that suggest the formation of hierarchical stacked βCD-C16 arrangement at the interface.

Non-linear van't Hoff behavior in pulmonary surfactant model membranes

Pulmonary surfactant exhibits phase coexistence over a wide range of surface pressure and temperature. Less is known about the effect of temperature on pulmonary surfactant models. Given the lack of studies on this issue, we used electron paramagnetic resonance (EPR) and nonlinear least–squares (NLLS) simulations to investigate the thermotropic phase behavior of the matrix that mimics the pulmonary surfactant lipid complex, i.e., the lipid mixture composed of dipalmitoyl phosphatidylcholine (DPPC), palmitoyl–oleoyl phosphatidylcholine (POPC) and palmitoyl–oleoyl phosphatidylglycerol (POPG). Irrespective of pH, the EPR spectra recorded from 5°C to 25°C in the DPPC/POPC/POPG (4:3:1) model membrane contain two spectral components corresponding to lipids in gel-like and fluid-like phases, indicating a coexistence of two domains in that range. The temperature dependence of the distribution of spin labels between the domains yielded nonlinear van't Hoff plots. The thermodynamic parameters evaluated were markedly different for DPPC and for the ternary DPPC/POPC/POPG (4:3:1) membranes and exhibited a dependence on chemical environment. While enthalpy and entropy changes for DPPC were always positive and presented a quadratic behavior with temperature, those of the ternary mixture were linearly dependent on temperature and changed from negative to positive values. Despite that, enthalpy-entropy compensation takes place in the two systems. The thermotropic process associated with the coexistence of the two domains is entropically–driven in DPPC and either entropically– or enthalpically–driven in the pulmonary surfactant membrane depending on the pH, ionic strength and temperature. The significance of these results to the structure and function of the pulmonary surfactant lipid matrix is discussed.

Profiling substrate specificity of Lecitase Ultra to different kinds of phospholipids using monolayer technology

Substrate specificity is a crucial parameter while characterizing an enzyme, which is directly related to the potential of its application. The commercial Lecitase Ultra has been widely used in the oil degumming process to specifically hydrolyze the phospholipids present in the crude oil, but its specificity for various phospholipids still remains elusive. In the present study, selectivity of Lecitase Ultra to different kinds of phospholipids was characterized under different surface pressure condition by using monolayer technology. Hydrolytic activity of Lecitase Ultra on various phospholipids was highly dependent on the surface pressure of monolayer film. Under the same surface pressure of 25 mN m−1 applied on the liquid condensed state of all the phospholipids’ monolayer films, the preference order of Lecitase Ultra to different monomolecular phospholipid film was PE &gt; CL &gt; PS &gt; PI &gt; PC. No hydrolytic activity was observed for sphingomyelin within the range of surface pressure tested. The present study provides basic information on the order of selective preference of Lecitase Ultra for various phospholipids which was not known previously, and provides additional information for better utilization of this enzyme in the oil industry.Practical applications: To the best of our knowledge, we have reported the application of monolayer technology to study the substrate selectivity of Lecitase Ultra to various natural phospholipids. This study contributes directly to applications of this enzyme in industries. Further, we try to prove that monolayer technology is very effective and simple for evaluating the enzymatic activity to some natural substrates, and should make greater contribution in the interfacial enzyme engineering field.Characterization on interfacial catalytic properties of Lecitase Ultra to different kinds of phospholipids using monolayer technique.

Mixed DPPC/POPC Monolayers: All-atom Molecular Dynamics Simulations and Langmuir Monolayer Experiments

To elucidate the consequences of the saturated-unsaturated nature of lipid surface films, monolayers formed by an equimolar mixture of 1-palmitoyl-2-oleyl-sn-glycero-3-phosphocholine (POPC) and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) lipids are investigated in a wide range of surface pressures. As such mixtures share some features with naturally-occurring surfactants, for example the lung surfactant, the systems are studied at the temperature relevant for human body. All-atom molecular dynamics simulations and Langmuir trough experiments are employed. The binary lipid mixture is compared with the corresponding one-component systems. Atomistic-level alterations of monolayer molecular properties upon lateral compression are scrutinized. These involve elevation of lateral ordering of lipid chains, modulation of chain and headgroup orientation, and reduction of lipid hydration. The presence of the unsaturated POPC in the DPPC/POPC mixture reduces the liquid expanded-liquid condensed coexistence region and moderates the phase transition. Simulations predict that nanoscale lipid de-mixing occurs with small transient DPPC clusters emerging due to local fluctuations of the lateral lipid arrangement. A vertical sorting of lipids induced by lateral compression is also observed, with DPPC transferred toward the water phase. Both the conformational lipid alterations due to monolayer compression as well as the existence of lateral dynamic inhomogeneities of the lipid film are potentially pertain to dynamic and non-homogeneous lipid interfacial systems.

Reversible Partitioning of Nanoparticles at an Oil–Water Interface

The reversible adsorption of nanoparticles (NPs) to oil-water interfaces has been observed experimentally, however, models capable of interpreting and predicting the equilibrium partitioning of particles between bulk media and fluid interfaces are still lacking. Here we characterize the adsorption of 5 nm gold NPs functionalized with ion-pair ligands at the toluene-water interface. Partitioning of the NPs between the bulk aqueous phase and the interface is measured via absorbance spectroscopy for two different aqueous-phase pH values (11.0 and 11.7) and over several orders of magnitude of aqueous phase NP concentration. The surface pressure of the interfacial film in equilibrium with the bulk aqueous phase is measured using the pendant drop method. We determine the range of surface pressure where the adsorption is reversible as well as conditions under which the adsorbed NPs are irreversibly adsorbed at the oil-water interface. We analyze together the adsorption and surface pressure isotherms to obtain the two-dimensional equations of state (EOS) for the NPs in equilibrium with the bulk aqueous phase. The experimental data are then compared to the Frumkin models. We find that the adsorption isotherm and the equation of state show good agreement at low coverage with the Frumkin equations; however, both curves cannot be described with the same parameters. We also show that the low-coverage portion of the EOS can also be described by a wetting model. We hypothesize that deviations from models at higher coverage are likely due to nonequilibrium effects and possible coadsorption.

β-Lactoglobulin adsorption layers at the water/air surface: 2. Dilational rheology: Effect of pH and ionic strength

The dynamic surface pressure Π and the two components E’ (real part) and E” (imaginary part) of the dynamic surface dilational modulus of adsorbed β-lactoglobulin (BLG) layers at the water/air interface were measured by oscillating drop/bubble profile analysis tensiometry with the aim to enlarge information on the surface rheology of solutions of this practically important protein. The effects of the solution pH and ionic strength (represented by the buffer concentration Cbuff) on the kinetic dependences of Π, E’ and E” were monitored for various protein concentrations in the range 5×10−9–2×10−4M. Combining the E’(t) and E”(t) data with the Π(t) data allowed for obtaining the dependences E’(Π) and E”(Π). The real part E’ was found to increase monotonically with increasing Π, while the E”(Π) data exhibit a maximum in the surface pressure range 14–18 mN/m. The height of the maximum in the E”(Π) dependence was found to increase with increasing protein concentration. Apparently, in these interfacial layers, relaxation processes take place and their relaxation strengths depend on the history of the layer formation, i.e. the rate of adsorption. After the maximum in the E”(Π) dependence the E”-values progressively diminish, which can be assumed to occur due to solidification of the protein gel-like network accompanied by less energy dissipation and high elasticity of the interfacial layer. BLG layers at pH 5 (close to the isoelectric point pI≈5.1) exhibit the highest E’-values and the lowest E”-values measured in this study, which suggest the formation of a strong protein network at these (isoelectric) conditions. Variations of the buffer concentration strongly influence the kinetic dependences of E’ and E” for BLG layers at pH≠pI, while at pH→pI no effect was detected. The viscoelastic characteristics of BLG layers adsorbed from buffer-free solutions containing NaCl or CaCl2 were also studied. For the first time, hysteresis in the frequency dependence of the surface dilational modulus of protein layers measured during repeating cycles of oscillations is reported. Such hysteresis is typical for BLG layers adsorbed at any solution conditions used in this study.