Charge Composition Research Articles

Study of the Structure and Properties of Steel G13 with Modifying and Organic Additives

The purpose of the study – is to determine the effect of modifying and organic additives on the structure and properties of G13 powder steel.Methods. The study of the microstructure and mechanical properties of G13 sludge with modifying and organic additives was carried out. As modifying additives were used: nano-aluminum oxide powder and nano-zirconium oxide powder. The following organic additives were used: ethylene-bis-stearomide, nickel stearate, copper stearate, manganese stearate, iron stearate. The microstructure was studied using an S-3400N electron microscope. Hardness was determined by the depth of the indentation by the Rockwell method. A hardened steel ball with a diameter of 1.56 mm was taken as an indenter. Bending tests were carried out on an MFL HUS-2010z electro-hydraulic tensile testing machine in automatic mode using an IBM PX personal computer.Results. When studying the microstructure of steel G13, it was found that the most fine-grained austenite structure is observed in steel with the following composition of the initial charge: Fe + 14.5% FeMn + 1.2% C + ZrO2 (nano). A uniform structure of austenite with small rounded pores is observed in steel G13, which has the following compositions of the initial charge: Fe + 13% FeMn + 1.3% C + 1% St.Cu; Fe + 14.5%FeMn + 1.2%C + 0.5% St.Mn (warm mix). The study of mechanical characteristics has shown that the best combination of hardness after sintering and bending strength is possessed by workpieces made from a powder mixture of composition Fe + 14.5% FeMn + 1.2% C + 0.5% St. Ni.Conclusion. The most positive effect on the structure of G13 powder steel was exerted by the modifying additive of nano-zirconium oxide powder, as well as organic additives of copper stearate and manganese stearate. The best combination of mechanical characteristics (hardness and bending strength) is exhibited by billets into which an organic additive of nickel stearate was introduced.

The Replacement of Quartz Sand with Microsilica for Obtaining Glass Materials

The article presents the physicochemical and technological characteristics of amorphous silica fume. According to the results of experimental studies, it can be established that the replacement of natural quartz sand with ferrosilicon waste–microsilica in the glass charge does not reduce its main physical, chemical and technological characteristics. It is shown that the replacement of quartz sand with microsilica in the raw material composition of the glass charge leads to a decrease in the temperature of smooth formation, in particular, glass melting, as a result of which it helps to save natural raw materials and energy resources, while solving the problems of improving the environmental situation in the industrial region of the Republic.

Role of Reservoir Brine and Rock in Modulating Asphaltene Stability: Insights from Experimental Analysis

Summary The stability of asphaltenes in crude oil is influenced by various factors, including interactions with reservoir components such as brine and rock formations. While previous research has focused on pressure and temperature effects, a comprehensive understanding of the combined impact of brine and reservoir rock on asphaltene stability is lacking. This study investigates the individual and combined influences of brine and rock formations on asphaltene stability. First, 11 crude oil samples from diverse locations were characterized using API gravity, viscosity, and saturates, aromatics, resins, and asphaltenes (SARA) fraction analysis. The elemental composition of the crude oils, including carbon, hydrogen, nitrogen, and various metals, was determined. The surface properties of asphaltenes were analyzed using scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS). The interaction between asphaltenes and deionized water was examined through zeta potential, particle size, conductivity, and pH measurements. The behavior of asphaltenes in an 8,000 ppm NaCl solution was also investigated. The SEM analysis revealed the presence of inorganic content on the surfaces of asphaltenes, indicating interactions between asphaltenes and reservoir rock. A strong correlation between the zeta potential and sulfur content of asphaltenes was observed, highlighting the influence of sulfur compounds on surface charge and stability in heavy crudes. Additionally, the correlation between total dissolved solids (TDS) content and alkaline Earth metals and alkali metals in asphaltenes confirmed interactions between asphaltenes and reservoir brine. This interaction is likely influenced by the composition and properties of both the brine and reservoir rock. The presence of electrical charges on the asphaltene surfaces, as determined by zeta potential measurements, further supports the role of electrostatic interactions in asphaltene stability. The low precipitation tendency observed for most asphaltene samples, coupled with the abundance of negatively charged particles, underscores the importance of electrical charges in controlling stability. This study provides novel insights into asphaltene stability, highlighting the significance of surface charge and elemental composition. The results demonstrate the substantial impact of both reservoir brine and rock formations on asphaltene stability in crude oil. Further research is needed to unravel the complex mechanisms underlying these interactions and their implications in diverse reservoir environments.

Variations of the initial charge composition and photodielectric effect in PbMoO4 single crystals

The photodielectric effect in lead molybdate (PbMoO4) single crystals grown by the Czochralski method in a direction 30° off the a-axis in the plain (001) was studied. The charge was prepared from MoO3 and PbO α- or β-modifications. The reagents were taken both in a stoichiometric ratio and with excess of 0.5 mol % MoO3. The temperature dependences of the permittivity ε on samples illuminated with UV-light were measured in the temperature range of 290–700 K. Assumptions about the relationship between the magnitude of the photodielectric anomalies and the disorder of the PbMoO4 crystal lattice were made.

Kinetics of Nisin-Induced Pore Formation in Giant Unilamellar Vesicles.

We have studied the kinetics of pore formation in giant unilamellar vesicles (GUV) with the antimicrobial peptide nisin. The role of charged lipid composition in the rate of pore formation by nisin in the vesicle membrane is investigated using fluorescence microscopy. We propose a model and obtain an analytical expression for the variation in the fluorescence intensity of a GUV as a function of time. We find that the analytical equation fits well to the experimental data, and the membrane surface potential can be estimated from the fit parameters. We further show that the formation of multiple pores on the vesicle membrane is affected by the charged lipid composition of the membrane.

Nanobio Interface Between Proteins and 2D Nanomaterials.

Two-dimensional (2D) nanomaterials have significantly contributed to recent advances in material sciences and nanotechnology, owing to their layered structure. Despite their potential as multifunctional theranostic agents, the biomedical translation of these materials is limited due to a lack of knowledge and control over their interaction with complex biological systems. In a biological microenvironment, the high surface energy of nanomaterials leads to diverse interactions with biological moieties such as proteins, which play a crucial role in unique physiological processes. These interactions can alter the size, surface charge, shape, and interfacial composition of the nanomaterial, ultimately affecting its biological activity and identity. This review critically discusses the possible interactions between proteins and 2D nanomaterials, along with a wide spectrum of analytical techniques that can be used to study and characterize such interplay. A better understanding of these interactions would help circumvent potential risks and provide guidance toward the safer design of 2D nanomaterials as a platform technology for various biomedical applications.

Influence of Powder Charge Composition on the Structure and Properties of T15K6 Hard Alloy

The purpose of the study is to determine the effect of nanosized additives on the structure and properties of the T15K6 hard alloy.Methods. These studies were carried out using an S-3400N electron microscope. The mechanical and physical properties of the structure of a hard alloy of the WC-TiC-Co system were studied using the example of T15K6 when nanosized tungsten powder and nanosized tungsten carbide powder with cobalt deposited on it were introduced into the initial charge using an optical and electron microscope; An X-ray spectrum analysis of the obtained samples of the T15K6 hard alloy was carried out on a DRON-4 X-ray diffractometer.Results. A hard alloy of the WC-TiC-Co system was studied with the introduction of nanosized tungsten powder into the initial charge, as well as with the introduction of nanosized tungsten carbide with cobalt deposited on its surface.In the work, the used powders of tungsten, nano-tungsten, cobalt, titanium carbide, tungsten carbide, nano-powder of tungsten carbide were studied, and the microstructure of the obtained hard alloys was also studied. It is shown that the coercive force of the T15K6 alloy depends on the size of the cobalt phase regions in the alloy; measuring its value makes it possible to judge the size of carbide grains. To improve the strength properties of hard alloys of the WC-TiCCo system, it is recommended to introduce nanosized WC additives or WC nanopowder with deposited cobalt.Conclusion. To improve the strength properties of hard alloys of the WC-TiC-Co system, it is recommended to introduce nanosized WC additives or WC nanopowder with deposited cobalt. The introduction of these additives into the composition of the powder charge of the T15K6 hard alloy leads to an increase in the ultimate bending strength by 15%. The introduction of nanosized WC additives or WC nanopowder with deposited cobalt makes it possible to obtain a fine-grained structure with a grain size of no more than 4–6 μm.

Impact of lock solutions on the mechanical performance of polyurethane central venous catheters: A comparative study.

The impact of ethanol locks on the mechanical performances of central venous catheters was compared to that of aqueous-based locks. Several mechanical tests were performed to evaluate catheter behavior: kinking radius measurements, burst pressure, and tensile tests. Different polyurethanes were studied to assess the impact of radio-opaque charge and polymer chemical composition on catheter behavior. The results were correlated to swelling measurements and calorimetric measurements. In particular, ethanol locks have a higher impact on long contact time than aqueous-based locks: stresses and strains at break were lower, and kinking radii were higher. However, for all catheters, the mechanical performances remain much higher than the normative requirements.

Designing engobe coatings for ceramic bricks

This paper reports research into the development of compositions of engobe coatings for ceramic bricks and investigating the influence of technological production factors on their physical and mechanical properties. The results of this work make it possible to solve the task of expanding the range and improving the operational properties of building ceramics. The data obtained have made it possible to establish physicochemical processes occurring during the formation of the phase composition and structure of engobe coatings. This has revealed the possibilities for designing engobe for various types of ceramic bricks, which differ in technological parameters of production and operational properties. The charge compositions were designed in a three-component system "refractory clay – quartz sand – cullet", taking into account the possibility of their practical implementation in large-tonnage production. It has been established that the most important condition for obtaining high-quality products is the correlation of shrinkage and temperature coefficients of linear expansion of the ceramic shard and engobe coating. To prevent various defects, these indicators should vary by no more than 10 %. The crystal-phase composition of engobe is represented by b-quartz and a small amount of devitrite, which are evenly distributed in a vitreous dense layer of coating on the surface of the ceramic shard. Distinctive features of the results relate to the fact that a solution to the problem of designing engobe coatings for ceramic bricks has been proposed and the physicochemical bases of production have been highlighted. This paper also suggests ways to achieve coordination of finely dispersed coatings with coarse-grained ceramic masses by shrinkage and thermal processes. The results reported here could be applied in typical production of face, clinker, and in some cases – ordinary brick or ceramic stone with firing temperatures of 950–1150 °C

Bridging Electrochemistry and Ultrahigh Vacuum: "Unburying" the Electrode-Electrolyte Interface.

ConspectusElectrochemistry has a central role in addressing the societal issues of our time, including the United Nations' Sustainable Development Goals (SDGs) and beyond. At a more basic level, however, elucidating the nature of electrode-electrolyte interfaces is an ongoing challenge due to many reasons, but one obvious reason is the fact that the electrode-electrolyte interface is buried by a thick liquid electrolyte layer. This fact would seem to preclude, by default, the use of many traditional characterization techniques in ultrahigh vacuum surface science due to their incompatibility with liquids. However, combined UHV-EC (ultrahigh vacuum-electrochemistry) approaches are an active area of research and provide a means of bridging the liquid environment of electrochemistry to UHV-based techniques. In short, UHV-EC approaches are able to remove the bulk electrolyte layer by performing electrochemistry in the liquid environment of electrochemistry followed by sample removal (referred to as emersion), evacuation, and then transfer into vacuum for analysis.Through this Account, we highlight our group's activities using UHV-EC to bridge electrochemistry with UHV-based X-ray and ultraviolet photoelectron spectroscopy (XPS/UPS) and scanning tunneling microscopy (STM). We provide a background and overview of the UHV-EC setup, and through illustrative examples, we convey what sorts of insights and information can be obtained. One notable advance is the use of ferrocene-terminated self-assembled monolayers as a spectroscopic molecular probe, allowing the electrochemical response to be correlated with the potential-dependent electronic and chemical state of the electrode-monolayer-electrolyte interfacial region. With XPS/UPS, we have been able to probe changes in the oxidation state, valence structure, and also the so-called potential drop across the interfacial region. In related work, we have also spectroscopically probed changes in the surface composition and screening of the surface charge of oxygen-terminated boron-doped diamond electrodes emersed from high-pH solutions. Finally, we will give readers a glimpse into our recent progress regarding real-space visualizations of electrodes following electrochemistry and emersion using UHV-based STM. We begin by demonstrating the ability to visualize large-scale morphology changes, including electrochemically induced graphite exfoliation and the surface reconstruction of Au surfaces. Taking this further, we show that in certain instances atomically resolved specifically adsorbed anions on metal electrodes can be imaged. In all, we anticipate that this Account will stimulate readers to advance UHV-EC approaches further, as there is a need to improve our understanding concerning the guidelines that determine applicable electrochemical systems and how to exploit promising extensions to other UHV methods.

Study of the properties of the metal deposited with flux-cored wire of the Fe‒C‒Si‒Мn‒Сr‒W‒V system.

Alloys of the Fe‒C‒Si‒Мn‒Сr‒W‒V system widely used for hot-rolling roll repairs provide high resistance of the deposited layer against abrasion, but its thermal endurance is relatively low. It is shown that in order to ensure the quality of roll repair, it is necessary to improve the composition of the flux-cored wire charge and the technology of their use. It is proposed to reduce the structural heterogeneity of the deposited metal the use of flux-cored wire of the type PP-Np-35V9X3SF. The influence of the introduction of carbon-fluorinated elements and titanium on hydrogen concentration, microstructure, level of pollution by non-metallic inclusions, grain size, hardness and rate of wear of the deposited metal layer was evaluated. The data on the chemical composition of the deposited layer, the content of non-metallic inclusions in it, the microstructure of the deposited metal, depending on the content of titanium in the flux-cored wire, are presented. It was found that an increase the concentration of titanium increases the hardness of the deposited layer and reduces the rate of wear (abrasion) of samples. The effect on the level of contamination of the studied fused layers with oxide inclusions was not revealed. Increasing the hydrogen content in the deposited layer re-duces its hardness and increases the rate of wear of the deposited layer. Increasing the content of titanium in the depos-ited layer helps to reduce the size of the martensite needles, as well as the size of the former austenite grain. The de-pendencies of HRC hardness and wear resistance on the content of titanium and hydrogen in the deposited layer were established

Exothermal reaction and microstructure study of the charged LiNi0.5Co0.2Mn0.3O2 electrode layers using argyrodite Li7−xPS6−xClx solid electrolytes

Sulfide-based solid electrolytes (SEs) are thermally stabler than liquid organic electrolytic solutions. However, sulfide-type all-solid-state batteries exhibit exothermic reactions during charge and discharge because sulfide-based SEs thermally react with the electrode active materials. Herein, we examined the exothermic behavior of a LiNi0.5Co0.2Mn0.3O2 (NCM523) positive electrode composite using argyrodite-type SEs. To clarify the exothermal mechanism of the NCM523 composites, the microstructural changes owing to heating were investigated via transmission electron microscopy (TEM). The charged NCM523 composites exhibited a conspicuous exothermic reaction at ∼200 °C. Ex situ TEM observations at 180 °C and 250 °C revealed that the SEs become considerably amorphized and nanocrystallites of Li2S and LiCl precipitate in the SE region at the SE/NCM523 interface. Energy-dispersive X-ray spectroscopy also revealed that oxygen disperses into the SE region. At 250–400 °C, furthermore, the charged NCM523 composites showed several exothermic reactions. Ex situ TEM observations at 400 °C revealed that nanocrytallites of transition metal sulfides, Li3PO4 and Li2SO4, are formed, which indicated that the SE thermally reacts with NCM523 and LiNbO3 coatings. These results suggest that the main exothermic reaction of the NCM523/argyrodite-type SE composites is attributable to the oxidative decomposition reaction of argyrodite-type SEs. To suppress exothermic reactions, it is necessary to prevent oxygen from dispersing into the SE. It is thus found that a coating material is one of the keys to improve the thermal stability of all-solid-state cells using sulfide-based SEs.

Influence of Carbon Content on the Formation of a Contact Interparticle Surface during Hot Post-Pressing

Introduction. The technology for producing hot-formed powder steel is one of the most energy-intensive in powder metallurgy, which includes a large number of operations. The study of the influence of technological modes on the final properties of the part is an urgent task. Developed by the scientific team under the leadership of Yu. G. Dorofeev at the end of the XX century, the technology of manufacturing hot-formed powder steels is currently one of the main ones in the production of high-density products. However, the use of new materials that improve the mechanical properties of products requires a modern approach to analyzing the quality of interparticle splicing of powder particles. The influence of the following technological factors on the formation of qualitative interparticle splicing was established: the blank density, the granulometric composition of the initial charge, the temperature and holding time of the blank during heating, the ratio of its dimensions, the deformation rate. The study objective is to analyze the effect of a graphite-containing component on the mechanical properties of hot-formed powder alloys due to the formation of high-quality interparticle splicing.Materials and Methods. The work used domestic and foreign powders produced by PAO Severstal and the Swedish company Höganäs with the addition of carbon GC-1 (GOST 4404-78). Hot stamping was carried out on a crank press of the K2232 model with a maximum force of 1600 kN. The heating temperature of the workpieces varied between 800-1200 ºC.Results. As a result of the experiments, the influence of the sintering duration on the mechanical properties of materials was established. The reason for the change in mechanical properties are local inclusions of graphite, which did not have time to homogenize as a result of prolonged sintering. Technological modes of hot stamping for steels have been developed that affect the preservation or destruction of the pre-formed contact interparticle surface.Discussion and Conclusion. The studies have shown that additional hot plastic deformation contributes to the formation of intracrystalline fusion on the entire contact surface. The addition of graphite to the charge improves splicing for alloyed iron powder and practically does not affect the use of alloyed and unalloyed iron powder.

Industrial utilization of complex, multicomponent technogenic formations and their safe movement

The description of slags produced by LLC «Klyuchevskaya concentrating factory» is given. Samples of metallic chromium, ferrochrome and ferrotitane slag are presented. The chemical composition of high-alumina refractory cements used for the production and the physico-mechanical properties of cements obtained by remelting metallic chromium slags are given. The chemical composition of the alumina intermediate obtained during the remelting of metallic chromium slags for the smelting of synthetic slags. Charge compositions during remelting of metallic chromium slags. The scheme of covering the bottom of the dump truck body is given. Ill. 5. Ref. 10. Tab. 3.

A simple semiempirical model for the static polarizability of ions

Abstract A concise analytical model for the static dipole polarizability of ionized atoms and molecules is created for the first time. As input, it requires, alongside the polarizability of neutral counterpart of a given ion, only the charge and elemental composition. This physically motivated semiempirical model is based on a number of established regularities in polarizability of charged monatomic and polyatomic compounds. In order to adjust it, the results of quantum chemistry calculations and gas-phase measurements available for a broad range of ionized multielectron species are employed. To counteract the appreciable bias in the literature data toward polarizability of monoatomic ions, for some molecular ions of general concern the results of the authors’ own density functional theory calculations are additionally invoked. A total of 541 data points are used to optimize the model. It is demonstrated that the model we suggested has reasonable (given the substantial uncertainties of the reference data) accuracy in predicting the static isotropic polarizability of arbitrarily charged ions of any size and atomic composition. The resulting polarizability estimates are found to achieve a coefficient of determination of 0.93 for the assembled data set. The created analytic tool is universally applicable and might be advantageous for some applications, where there is an urgent need for rapid low-cost evaluation of the static gas-phase polarizability of ionized atoms and molecules. This is especially relevant to constructing the complex models of nonequilibrium chemical kinetics aimed at precise describing the observable refractive index (dielectric permittivity) of plasma flows. The data sets that support the findings of this study are openly available in Science Data Bank at https://...

Rigid-plastic membrane response of thin plates under impulsive blast loads using the extended Hamilton principle

The response of plates subjected to blast loads is of considerable scientific interest. The loading imparted to a structure following a close-in detonation of a high explosive is typically high in magnitude, near-impulsive, spatially non-uniform, with localised variability and a high dependence on factors such as charge shape, position, and composition. The resulting structural response may induce large displacements in materials whose properties may not be fully characterised. In order to properly account for the effects of such intrinsic and extrinsic uncertainties, modelling approaches must balance the competing demands of accuracy and low computational demand. This article applies the extended Hamilton’s principle to rigid-plastic thin plates subjected to impulsive blast loads to derive the governing equation of motion without a prior assumption of the initial specific impulse distribution. Closed-form solutions to predict the plastic response are derived for rectangular and circular plates. The analytical models for uniform specific impulses are found to be in good agreement with high-fidelity numerical simulations performed using LS-DYNA and experimental data available in the literature.

Studies of the thermal stability of briquettes based on microsilica

The object of study in this work is microsilica. Microsilica is a pulverized technogenic waste generated during the smelting of technical silicon in industries. The intended use of this material is to obtain the highest quality grades of technical silicon in the end result without the use of expensive quartz. Microsilica is a finely dispersed powder, the direct processing (without preliminary preparation) of which into technical silicon is impossible in ore-thermal furnaces. That requires the manufacture of high-strength briquettes based on it, meeting all the requirements for raw materials for ore-thermal furnaces. In this paper, the authors present the results of a study of the thermal stability of microsilica-based briquettes in order to optimize the physicochemical properties of the resulting briquettes. The tested microsilica briquettes with various carbonaceous reducing agents (screenings of coke of thermo-oxidative coking, screenings of charcoal, etc.) were obtained on a large-scale laboratory roller briquetting press ZZXM-4. The evaluation of the thermal stability of the briquettes was carried out according to the method in which the resulting briquettes are subjected to thermal shock followed by abrasion on a special drum. The thermal resistance of a briquette is defined as the ratio of the weight of the main body of the briquette after the abrasion test to the sum of the weight of the main body and the crumbled material. The dependence of thermal stability on the granulometric composition of briquettes was also determined. The optimal granulometric composition was determined, with which the briquettes have satisfactory thermal stability. Thus, the most technologically advanced granulometric composition of the briquetting charge for reduction smelting in an ore-thermal furnace was established. It is best to use briquettes with granulometric compositions of the appropriate ratio of fractions 0-1; 1-3; 3-5 mm with the following proportions 35/35/30 and 60/20/15, as well as briquettes with particle size distribution within these ranges of variation.

Nanoparticles in Plants: Uptake, Transport and Physiological Activity in Leaf and Root.

Due to their unique characteristics, nanoparticles are increasingly used in agricultural production through foliage spraying and soil application. The use of nanoparticles can improve the efficiency of agricultural chemicals and reduce the pollution caused by the use of agricultural chemicals. However, introducing nanoparticles into agricultural production may pose risks to the environment, food and even human health. Therefore, it is crucial to pay attention to the absorption migration, and transformation in crops, and to the interaction with higher plants and plant toxicity of nanoparticles in agriculture. Research shows that nanoparticles can be absorbed by plants and have an impact on plant physiological activities, but the absorption and transport mechanism of nanoparticles is still unclear. This paper summarizes the research progress of the absorption and transportation of nanoparticles in plants, especially the effect of size, surface charge and chemical composition of nanoparticle on the absorption and transportation in leaf and root through different ways. This paper also reviews the impact of nanoparticles on plant physiological activity. The content of the paper is helpful to guide the rational application of nanoparticles in agricultural production and ensure the sustainability of nanoparticles in agricultural production.

Sustainable charged composites with amphiphobic surfaces for harsh environment–tolerant non-contact mode triboelectric nanogenerators

In this work, the sustainable charged composites with amphiphobic surfaces are reported regarding harsh environment tolerance and robust contactless mode triboelectric nanogenerators (TENGs). SiO2 and polytetrafluoroethylene (PTFE) particles are well dispersed in thermoplastic polyurethane (TPU) and polydimethylsiloxane (PDMS), respectively. Both surfaces become very rough after a chemical etching method and the surface of PTFE-PDMS is fluorinated using a fluorinated alkylsilane, resulted in the formation of amphiphobic surfaces. This significantly enhances the environment tolerance of the contactless mode TENGs as well as the charge retention characteristics of the composites. As a practical non-contact mode application, a speed sensor fabricated using two composites can stably detect a low vehicle speed less than 3.75 km/h when exposed to high humidity (∼ 99%) and various chemical oils. Over 50% of initial output voltage are still generated after 2 weeks with no more decrease after 5 days, showing a 1.4 times slower charge decay rate, compared with the reference Ni-PTFE based TENG.

HIV-1 Gag specificity for PIP2 is regulated by macromolecular electric properties of both protein and membrane local environments

HIV-1 assembly occurs at the plasma membrane, with the Gag polyprotein playing a crucial role. Gag association with the membrane is directed by the matrix domain (MA), which is myristoylated and has a highly basic region that interacts with anionic lipids. Several pieces of evidence suggest that the presence of phosphatidylinositol-(4,5)-bisphosphate (PIP2) highly influences this binding. Furthermore, MA also interacts with nucleic acids, which is proposed to be important for the specificity of GAG for PIP2-containing membranes. It is hypothesized that RNA has a chaperone function by interacting with the MA domain, preventing Gag from associating with unspecific lipid interfaces. Here, we study the interaction of MA with monolayer and bilayer membrane systems, focusing on the specificity for PIP2 and on the possible effects of a Gag N-terminal peptide on impairing the binding for either RNA or membrane. We found that RNA decreases the kinetics of the protein association with lipid monolayers but has no effect on the selectivity for PIP2. Interestingly, for bilayer systems, this selectivity increases in presence of both the peptide and RNA, even for highly negatively charged compositions, where MA alone does not discriminate between membranes with or without PIP2. Therefore, we propose that the specificity of MA for PIP2-containing membranes might be related to the electrostatic properties of both membrane and protein local environments, rather than a simple difference in molecular affinities. This scenario provides a new understanding of the regulation mechanism, with a macromolecular view, rather than considering molecular interactions within a ligand-receptor model.