Chemical Structure Of Surfactants Research Articles

Structure-based modeling of critical micelle concentration (CMC) of anionic surfactants in brine using intelligent methods

Critical micelle concentration (CMC) is one of the main physico-chemical properties of surface-active agents, also known as surfactants, with diverse theoretical and industrial applications. It is influenced by basic parameters such as temperature, pH, salinity, and the chemical structure of surfactants. Most studies have only estimated CMC at fixed conditions based on the surfactant’s chemical parameters. In the present study, we aimed to develop a set of novel and applicable models for estimating CMC of well-known anionic surfactants by considering both the molecular properties of surfactants and basic affecting factors such as salinity, pH, and temperature as modeling parameters. We employed the quantitative-structural property relationship technique to employ the molecular parameters of surfactant ions. We collected 488 CMC values from literature for 111 sodium-based anionic surfactants, including sulfate types, sulfonate, benzene sulfonate, sulfosuccinate, and polyoxyethylene sulfate. We computed 1410 optimized molecular descriptors for each surfactant using Dragon software to be utilized in the modelling processes. The enhanced replacement method was used for selecting the most effective descriptors for the CMC. A multivariate linear model and two non-linear models are the outputs of the present study. The non-linear models were produced using two robust machine learning approaches, stochastic gradient boosting (SGB) trees and genetic programming (GP). Statistical assessment showed highly applicable and acceptable accuracy of the newly developed models (RSGB2 = 0.999395 and RGP2 = 0.954946). The ultimate results showed the superiority and greater ability of the SGB method for making confident predictions.

Performance evaluation of different cationic surfactants as anti-swelling agents for shale formations

In this study, three different novel cationic surfactants decyl-trimethyl-ammonium bromide (S1), Octyl-trimethyl-ammonium bromide (S2), hexyl-trimethyl-ammonium bromide (S3) were used to formulate water-based drilling formulations to comprehend the interactions between drilling fluids components and with wellbore formations. The modified drilling formulations were prepared by incorporating novel surfactants in the base mud along with other additives such as bentonite, PAL-C, xanthan gum, and barite. The effect of the surfactant's chemical structure was assessed by rheology and filtration experiments, and colloidal dispersion stability was determined by particle size distribution analysis and sedimentation tests. The shale swelling inhibition characteristics of surfactant-based formulations were accessed by hot rolling dispersion tests, linear swelling rates, and capillary suction time tests. The performance of surfactant-based formulations for shale swelling inhibition was compared with KCl-based and conventionally used base mud formulations. The surface wettability of shale in the presence of different formulations was assessed by a high-resolution optical tensiometer. Shale inhibition properties of surfactant-based formulations depict that shale dispersion recovery increased to 98% for BS1 formulation compared to all other used formulations. Linear swelling of shale pellet show that the swelling rate of BS1 formulation was only 13% compared to all other formulations. The contact angle experiments showed that the BS1 formulation increased the contact angle of a water droplet and reduced the wettability of drilling fluids. The experimental results showed that S1 surfactant has enhanced shale inhibition characteristics compared to other surfactants and conventionally used shale inhibitors.

Effect of mixed nonionic surfactants on microemulsion phase boundary, fuel property, and engine performance of biofuels

Microemulsion biofuels can become one of alternative biodiesels using suitable nonionic surfactants and cosurfactant to emulsify vegetable oil and ethanol with the appropriate formulae. Without the further chemical improvement, the low volatility and high viscosity because of triglycerides in vegetable oil can cause a serious problem in engine operation. This work proposed a systematic investigation of microemulsion biofuel prepared from rice bran oil and ethanol using mixed nonionic surfactant systems (Dehydol LS7, Tween 80, and Span 80) as surfactant (S) and 1-octanol as a cosurfactant (C) at molar ratio of 1:30. Microemulsion phase behaviors can be examined through the ternary phase diagram of rice bran oil, ethanol, and S:C. It was observed that Dehydol LS 7 was poor in solubilization of rice bran oil and ethanol because of their preference in hydrophilic compounds rather than lipophilic compounds. Introduction of Tween 80 or Span 80 into the biofuels using Dehydol LS 7 enhanced the solubilization of these systems as the extent of single-phase boundary was significantly enlarged because of the hydrophilic–lipophilic balance of the mixture and chemical structure of surfactants. The fuel properties of microemulsion biofuel were investigated through kinematic viscosity, specific gravity, flash point, cloud point, pour point, and higher heating value. It was found that mixed surfactant also improved some fuel properties due to additional surfactants contain many oxygenated functional groups, however, some parameters were slightly substandard. The combustion characteristics and exhaust emission were investigated in CI diesel engine. It was observed that the in-cylinder pressure was lower under the combustion of microemulsion fuel mainly due to the high latent heat of vaporization of alcohols. The start of combustion was more retarded with the addition of Span 80, especially at low load condition. It was observed that the significant reduction in nitrogen oxides was achieved with the combustion of microemulsion fuel while unburnt hydrocarbon emissions were higher compared to diesel fuel. The obtained experimental data showed that microemulsion biofuels can be a promising alternative biodiesel although the individual usage in engine was slightly less efficient than commercial diesel fuel.

Influence of organic and inorganic precipitators on the efficiency of surfactants extraction from wastewater by flotation

The chemical structure of surfactants causes their accumulation on the surface of water sources and leads to the formation of stable foam, which prevents the access of oxygen to the water and leads to the death of hydrobionts and deterioration in water quality. Therefore, the extraction of surfactants from wastewater is an urgent task. Increase the efficiency of flotation extraction of cationic surfactants, namely hexadecyl pyridinium chloride [C 16 H 33 NC 5 H 5]Cl (CHDP) and surfactants based on it - cetazol, by introducing organic – (sodium alkyl sulfate (SAS), CnH 2n+1 OSO 3 Na, n=10-16), and inorganic - potassium hexacyanoferrate (II, III) precipitators. The solubility of the products of interaction of cationic surfactants with SAS (sublates) was determined, which are extracted from solutions at different temperatures and impurities of electrolytes. The Gibbs free energy (), enthalpy (), and entropy (), which take place in the process of dissolution, are calculated. The low value of the heat of dissolution (2.1-16.6 kJ/mol) indicates a small effect of temperature on the solubility of sublates. The thermodynamic analysis of the process of formation of sublates allows determining the optimal length of the hydrocarbon radical of the precipitator. It is established that the extraction of the studied cationic surfactants should be extracted from water solutions and wastewater by the method of precipitation flotation using organic and inorganic precipitators. The presence of electrolytes and an increase in temperature leads to an increase in the degree of extraction hexadecyl pyridinium alkyl sulphonates sublates.

Study of the spontaneous nano-emulsification process with different octadecyl succinic anhydride derivatives

Three new amphiphilic molecules were synthetized on a basis of a common monomer, octadecyl succinic anhydride (OSA), on which were grafted different PEGylated hydrophilic polar head. The objective of this study is to investigate a potential relationship between the chemical structure of the surfactant, and the efficiency to generate nano-emulsions through the spontaneous nano-emulsification method. Beyond the innovative synthesis and comparison of these amphiphiles, a comprehensive comparison is suggested, comparing size distribution and polydispersity for the different composition parameters, as well making a bridge with critical micelle concentration and hydrophile lipophile balance (HLB). Using OSA monomeric entity as common hydrophobic moiety, the variations in the surfactant molecules were done on the hydrophilic moiety, through the addition of one or two Jeffamine chains in different configurations, so-called C18⊖-PEG, C18-PEG and C18-PEG2. The results disclosed that C18⊖-PEG allows producing smallest size distribution and lowest PDI values. Moreover, C18⊖-PEG presents the highest critical micellar concentration, linked to a higher hydrophilicity of the molecule. This impacts the balance between surfactant affinity for oil and aqueous phases, a point probably related to the spontaneous emulsification efficiency. A last part of the study regarded the optimization of the emulsification efficiency, through a systematic study in ternary composition map, to disclosed that the best conditions are included in the lower surfactant concentrations, for water and oil contents higher and lower than 50%, respectively. The main idea behind this study was to bring further insights into the unclear relationship between the chemical structure of nonionic surfactants, and the efficiency of the emulsification by spontaneous low-energy method.

Predator-prey interactions between droplets driven by non-reciprocal oil exchange.

Chemotactic interactions are ubiquitous in nature and can lead to non-reciprocal and complex emergent behaviour in multibody systems. However, developing synthetic, inanimate embodiments of a chemomechanical framework to generate non-reciprocal interactions of tunable strength and directionality has been challenging. Here we show how chemotactic signalling between microscale oil droplets of different chemistries in micellar surfactant solutions can result in predator-prey-like non-reciprocal chasing interactions. The interactions and dynamic self-organization result from the net directional, micelle-mediated transport of oil between emulsion droplets of differing composition and are powered by the free energy of mixing. We systematically elucidated chemical design rules to tune the interactions between droplets by varying the oil and surfactant chemical structure and concentration. Through the integration of experiment and simulation, we also investigated the active behaviour and dynamic reorganization of multidroplet clusters. Our findings demonstrate how chemically minimal systems can be designed with controllable, non-reciprocal chemotactic interactions to generate emergent self-organization and collective behaviours reminiscent of biological systems.

Novel Structural Increments for Estimating the Krafft Temperature of Ionic Surfactants in Aqueous Solutions

AbstractIn this work, we report results of our investigation on the relationship between the Krafft temperature of ionic surfactants in aqueous solutions and their chemical structure. We tested empirical values of the Krafft temperature available in literature for aqueous solutions of 234 ionic surfactants and correlated them to the surfactant chemical structure. In this work, we propose a novel set of 67 group contributions for calculation of the Krafft temperature of ionic surfactants in aqueous solutions. Using them, the Krafft temperature values in aqueous solutions for 174 anionic, 43 cationic, and 17 zwitterionic surfactants were calculated and the estimated values obtained in this way were compared with experimental values. We have demonstrated that the newly developed set of numerical values structural group contributions of the surfactants allows correct estimation of the Krafft temperature value for the tested set of data with the maximum error 7.6°C and the mean square error 3.7°C for various types of ionic surfactants in aqueous solutions.

Cationic Surfactants: Self-Assembly, Structure-Activity Correlation and Their Biological Applications.

The development of biotechnological protocols based on cationic surfactants is a modern trend focusing on the fabrication of antimicrobial and bioimaging agents, supramolecular catalysts, stabilizers of nanoparticles, and especially drug and gene nanocarriers. The main emphasis given to the design of novel ecologically friendly and biocompatible cationic surfactants makes it possible to avoid the drawbacks of nanoformulations preventing their entry to clinical trials. To solve the problem of toxicity various ways are proposed, including the use of mixed composition with nontoxic nonionic surfactants and/or hydrotropic agents, design of amphiphilic compounds bearing natural or cleavable fragments. Essential advantages of cationic surfactants are the structural diversity of their head groups allowing of chemical modification and introduction of desirable moiety to answer the green chemistry criteria. The latter can be exemplified by the design of novel families of ecological friendly cleavable surfactants, with improved biodegradability, amphiphiles with natural fragments, and geminis with low aggregation threshold. Importantly, the development of amphiphilic nanocarriers for drug delivery allows understanding the correlation between the chemical structure of surfactants, their aggregation behavior, and their functional activity. This review focuses on several aspects related to the synthesis of innovative cationic surfactants and their broad biological applications including antimicrobial activity, solubilization of hydrophobic drugs, complexation with DNA, and catalytic effect toward important biochemical reaction.

Influence of hydrophilic silica nanoparticles on the adsorption layer properties of non-ionic surfactants at water/heptane interface

There is a notable paucity of studies investigating the impact of charged nanoparticles on the interfacial behavior of nonionic surfactants, assuming that the interactions are negligible in the absence of electrostatic forces. Here, we argue about our observations and the existence of a complex interfacial behavior in such systems depending on the type and chemical structure of surfactant. This study set out to investigate the effects of interactions between hydrophilic silica nanoparticles (NP) and non-ionic surfactants on water/heptane dynamic interfacial properties using drop profile analysis tensiometry (PAT). Three surfactants were studied, namely Triton X-100 (significantly soluble in water phase), C12DMPO (well soluble in both phases) and SPAN 80 (oil-soluble). The different chemical structures and partition coefficients of the surfactants enabled us to cover possible interactions and differentiate between bulk and interfacial interactions. We observed that hydrophilic silica NPs had a negligible effect on the interfacial behavior of Triton X-100, that they increased the surface activity of C12DMPO when both compounds are initially in the aqueous phase. Most interestingly is that the added NPs generated unstable interfacial NP-surfactant complexes and reduced the pseudo-equilibrium interfacial tension of oil-soluble surfactant, Span 80, even though NPs and surfactants were in different bulk phases.

Solvent Free Synthesis, Characterization and Evaluation of Dimethylaminopropylamine based Double Tailed Amidoamine Cationic Surfactant

Lauramidopropyl dimethylamine was quaternised using Lauryl Bromide to synthesize a double chain cationic surfactant. The surfactant was obtained in good yield without the use of any solvent. Amidoamine cationic surfactant chemical structure was analyzed using mass spectroscopic technique. The physicochemical properties of the amidoamine surfactant were calculated from surface tension and conductance measurements giving a critical micelle concentration of 8.04 × 10 -3 mM which is quite lower than conventional surfactants. The amidoamine also exhibits a good foaming ability and wettability. The amidoamine cationic surfactant was evaluated for efficacy against different microorganisms and the results show that it has good antimicrobial activity against both Gram positive and Gram negative bacteria.

Особливості біохімічного складу сурфактанта легень щурів при гострому респіраторному дистрес-синдромі

Introduction. Despite significant scientific advances in the understanding of the clinical and pathobiochemical aspects of acute respiratory distress syndrome (ARDS), there is no specific therapy. This substantiates the search for new mechanisms of the impact of damaging factors on pulmonary tissue and the body of patients with ARDS.The aim of the study – to analyze the chemical composition of the pulmonary surfactant in the dynamics of acute respiratory distress syndrome in rats.Research Methods. Experiments were conducted on 60 white nonlinear male-rats, which were modulated acute lung injury by intratracheal administration of hydrochloric acid at pH 1.2 at a dose of 1.0 ml/ kg per breath.The content of phospholipids, triacylglycerols, free fatty acids and cholesterol was determined in the pulmonary tissue homogenate. The biochemical study of surfactant phospholipids was performed by thin layer chromatography.Results and Discussion. The results of the study indicate an increase of cholesterol and free fatty acids concentration in the pulmonary homogenate in the dynamics of ARDS. In contrast to the content of cholesterol and free fatty acids in the tissues of the lungs, the concentration of triacylglycerols and phospholipids are decreased. The obtained data indicate that the chemical structure of the surfactant is violated by ARDS, which leads to the decreasingof its functional capacity. Against the background of a marked reduction in the content of phosphatidylcholine, an increase in lysophosphatidylcholine, the percentage of phosphatidylethanolamine, sphingomyelin, phosphatidylinositol and phosphatidylserine increased in a compensatory manner. It should be noted that these values reached their maximum value in 5 research groups, in particular, after 24 hours, the content of phosphatidylethanolamine was higher by 48.4% vs control indicators, respectively, sphingomyelin – by 22.0%, phosphatidylinositol – by 37, 7% and phosphatidylserine – by 35.0%.Conclusions. In case of acute respiratory distress syndrome in rats, the chemical structure of surfactant is altered due to changes in lipid metabolism: cholesterol and free fatty acids had increased, levels of triacylglycerols and total phospholipids had decreased in pulmonary homogenate in the dynamics of the studied pathology. The obtained data indicate a decrease in the surfactant synthesizing capacity of the lungs with respiratory distress syndrome.

Supramolecular "Big Bang" in a Single-Ionic Surfactant/Water System Driven by Electrostatic Repulsion: From Vesicles to Micelles.

In aqueous solution, dimethyldi-n-octylammonium chloride, [DiC8][Cl], spontaneously forms dimers at low concentrations (1-10 mM) to decrease the strength of the hydrophobic-water contact. Dimers represent ideal building blocks for the abrupt edification of vesicles at 10 mM. These vesicles are fully characterized by dynamic and static light scattering, self-diffusion nuclear magnetic resonance, and freeze-fracture transmission electron microscopy. An increase in concentration leads to electrostatic repulsion between vesicles that explode into small micelles at 30 mM. These transitions are detected by means of surface tension, conductivity, and solubility of hydrophobic solutes as well as by isothermal titration microcalorimetry. These unusual supramolecular transitions emerge from the surfactant chemical structure that combines two contradictory features: (i) the double-chain structure tending to form low planar aggregates with low water solubility and (ii) the relatively short chains giving high hydrophilicity. The well-balanced hydrophilic-hydrophobic character of [DiC8][Cl] is then believed to be at the origin of the unusual supramolecular sequence offering new opportunities for drug delivery systems.

Nonionic surfactant structure on the drug release, formulation and physical properties of ethylcellulose microspheres

Evaluate the effects of nonionic surfactants Brij 58 and Tween 40 with different structures but similar hydrophilic lipophilic balances (HLBs) on theophylline (TH)-loaded ethylcellulose (EC) microspheres. Microspheres were formulated using ratios of the surfactants with matching HLB values but different chemical-structures at temperatures (22/35 °C) by hydrophobic solvent-emulsion evaporation. Particle size, GMD, drug loading, encapsulation efficiency and dissolution were evaluated. Drug release was determined using the zero- and first-order, Higuchi and Hixson–Crowell models. EC microspheres prepared with surfactant Brij 58 showed discrete, free-flowing spherical particles, solid interiors and increased particle smoothness as temperature increased; those prepared with Tween 40 appeared porous with coarser surface morphology as temperature increased; both were CHLB (Combined HLB) dependent. Dissolution obeyed the Higuchi model drug release for both microspheres prepared with Tween 40 and Brij 58 except for those prepared with Brij 58 at 35 °C, which presented as zero order. The results were ascribed to the different chemical structure of Brij 58 versus Tween 40 and preparation temperature. Surfactant chemical structure is an unreported processing parameter shown here to be important in microsphere formulation. Brij 58 possesses properties unique to its chemical structure that influence pharmaceutical and molecular biopharmaceutical research.

Implementing radial basis function neural network for prediction of surfactant retention in petroleum production and processing industries

ABSTRACTChemical flooding is an effective way to gain higher oil recovery as part of a tertiary oil recovery scheme. There are several variables contribute in surfactant retention in petroleum production including type of rock, pH, chemical structure of surfactant, salinity of formation water, acidity of oil, mobility, microemulsion viscosity, and cosolvent concentration. Although different theoretical studies on the mechanisms of surfactant retention are reported in the literature there is little research on the development of an accurate and effective model for prediction of surfactant retention in petroleum production. In this study, radial basis function was developed based on experimental dynamic surfactant retention data. The experimental data include a wide range of conditions. Results of the modeling study showed that the developed model is very accurate and robust in prediction of actual surfactant retention data. In addition, the comparison between the proposed model in this study and available models in literature showed the superiority of this model.

Effects of Interaction of Gemini Ester Quat Surfactants with Biological Membranes

Abstract The aim of the study was to determine the relation between the biological activity of two homologous series of cationic gemini surfactants, which are quaternary ammonium salts, and their structure. The measure of the biological activity of the compounds was assumed to be the effects they exert on the membrane of erythrocytes, treated as a simple model of the biological membrane. In particular, it was determined the effects of the compounds on hemolysis and the osmotic resistance of erythrocytes and the fluidity of erythrocyte membrane, and the packing arrangement of the polar heads of membrane lipids. The results have shown that surfactants affect the osmotic resistance of erythrocytes to various degrees, and at sufficiently high concentrations operate destructively on their membrane, eventually causing hemolysis, modify the fluidity of erythrocyte membrane and affect the arrangement of polar heads of membrane lipids. Additionally, the results showed that that activity depends on a surfactant's chemical structure, in particular, on the length of its alkyl chain and structure of the polar head group that determines the spacing between the chains. In both used new series the compounds containing 10, 12 and 14 carbon atoms in a chain possess a high biological activity. In addition, the surfactants with larger spaces between the chains are more active than those with smaller spacing. The investigations have revealed a high activity of compounds with longer chains and bigger polar heads. The results of the study may find application when designing a molecular structure and synthesizing new compounds of specific, desired activity.

Impact of non-ionic surfactant chemical structure on morphology and stability of polystyrene nanocomposite latex

Polystyrene (PS) colloid particles in presence of non-ionic surfactant-modified clay particles were prepared by the free-radical polymerization of styrene monomers in emulsion. Three different types of non-ionic surfactants, sorbitan monopalmitate (Span®40), polyethylene glycol octadecyl ether (Brij®S10), and polyoxyethylene (9) nonylphenylether (Igepal®Co-630) were used for the preparation of surfactant-modified clay. High-resolution transmission electron microscopy studies showed that few colloid PS particles with clay mineral layers at the surface were obtained; the particle sizes were observed to be in the micrometer size range, and stable dispersions were obtained when Span®40 and Igepal®Co-630 modified clay minerals were used as stabilizers. The clay mineral particles were observed to be mostly encapsulated by PS latex particles, and a typical morphology was observed when Brij®S10-modified clay was used as a stabilizer. This strategy can be applied to develop stable polymer latex particles via emulsion polymerization.

Tailoring the reactivity of bio-surfactants as a tool for montmorillonite exfoliation in epoxy thermosets

It is well established that the chemical structure of surfactants used to promote the dispersion of clay minerals in polymers plays a major role in clay polymer nanocomposites preparation. However, much less explored is the incorporation of reactive surfactants capable of covalently grafting to monomers and polymer chains. In this work, the effect of the reactivity degree of bio-based surfactants onto the exfoliation of montmorillonite in epoxy is evidenced. For this purpose, 3 surfactants were prepared from a derivative of Cardanol, incorporating reactive groups: N(CH3)2, NH2 or two NH2 functions. In each case, the organomodification of the clay mineral results in a similar interlayer space increase. Combined chemical derivatization and MALDI-TOF/MS was used to evidence the differences of the residual reactivity of the intercalated surfactants. Finally each organomodified clay mineral was used for the preparation of epoxy nanocomposites. Interestingly, for the most reactive surfactant, X-ray diffraction analysis evidenced a fully exfoliated structure while semi-exfoliation or intercalated structure was found for the less reactive surfactants.

Synthesis, characterization, surface and biocidal effect of some germinate nonionic surfactants

Different fatty acid namely; palmitic, stearic, oleic and linoleic acids and polyethylene glycol-600 were reacted to give nonionic surfactants. The formed nonionic surfactants were reacted with germanium dioxide in presence of sodium carbonate to form germinates nonionic surfactants (I, II, III, and IV). The chemical structures of the synthesized surfactants were characterized by FT-IR and 1H-NMR spectra. The synthesized surfactants showed higher surface activity at different temperature and surface parameters influenced by chemical structure of surfactants. The thermodynamic calculations showed that adsorption and micellization processes are spontaneous. The synthesized surfactants showed good antimicrobial activities against the tested microorganisms including Gram positive, Gram negative as well as fungi. The promising inhibition efficiency of these compounds against the sulfate reducing bacteria facilitates them to be applicable in the petroleum field as new categories of sulfate reducing bacteria biocides.

Thermodynamics of micellization of homologous series of alkyl mono and di-glucosides in water and in heavy water

In this study, isothermal titration calorimetry was used to follow the micellization of two homologous series of alkylglucoside surfactants from heptyl to nonylmonoglucosides and from octyl to dodecyldiglucosides over the temperature range from (15 to 65)°C. These measurements allowed the calculation of the thermodynamic parameters associated with micelle formation, viz.: Gibbs free energy, enthalpy, entropy and heat capacity changes. Moreover, micellization of one of these surfactants, nonylmonoglucoside, was also investigated in heavy water, D2O, at different temperatures for comparison.Overall, these results conformed very well with the behaviour displayed by other surfactants with respect to changes within the homologous series. Use of additivity schemes provided estimates of contributions from the polar head group and the methylene units to these thermodynamic functions. The good agreement between the results for alkylglucosides micellization and literature data for other surfactants confirms that, with respect to the hydrophobic interior, their micelles display similar properties. The same can be said about the temperature dependence for micellization, which follows that of other surfactants. Two specific issues were investigated. First the contributions from one versus two glucoside units in the surfactant chemical structure were assessed, which turned out to be essentially the same because the data for the two families of surfactants could be superimposed within their experimental uncertainty. The second addressed possible differences regarding micelle formation in normal and heavy water. In this respect, data for the micellization of one of these surfactants provided values for the thermodynamic functions in D2O that could be considered only slightly different from those in H2O.

Phospholipid Bilayer-Perturbing Properties Underlying Lysis Induced by pH-Sensitive Cationic Lysine-Based Surfactants in Biomembranes

Amino acid-based surfactants constitute an important class of natural surface-active biomolecules with an unpredictable number of industrial applications. To gain a better mechanistic understanding of surfactant-induced membrane destabilization, we assessed the phospholipid bilayer-perturbing properties of new cationic lysine-based surfactants. We used erythrocytes as biomembrane models to study the hemolytic activity of surfactants and their effects on cells' osmotic resistance and morphology, as well as on membrane fluidity and membrane protein profile with varying pH. The antihemolytic capacity of amphiphiles correlated negatively with the length of the alkyl chain. Anisotropy measurements showed that the pH-sensitive surfactants, with the positive charge on the α-amino group of lysine, significantly increased membrane fluidity at acidic conditions. SDS-PAGE analysis revealed that surfactants induced significant degradation of membrane proteins in hypo-osmotic medium and at pH 5.4. By scanning electron microscopy examinations, we corroborated the interaction of surfactants with lipid bilayer. We found that varying the surfactant chemical structure is a way to modulate the positioning of the molecule inside bilayer and, thus, the overall effect on the membrane. Our work showed that pH-sensitive lysine-based surfactants significantly disturb the lipid bilayer of biomembranes especially at acidic conditions, which suggests that these compounds are promising as a new class of multifunctional bioactive excipients for active intracellular drug delivery.