Mixtures Of Nonionic Surfactants Research Articles

The Response Surface Methodology for Assessment of HLB Values of Mixtures of Non-Ionic Surfactants Using Parameters from Their π-A Isotherms.

The aim of the work was to determine important parameters of the course of π-A isotherms, which can determine the HLB (hydrophilic-lipophilic balance) value of surfactant mixtures with selected structural features, such as a straight or branched hydrocarbon chain and a double bond, using RSM (response surface methodology) computational methods. Mixtures of surfactants derived from fatty acids and sorbitan with specific HLB values were evaluated by Langmuir trough. The resulting elasticity modules (ELM) and molecules surfaces (SAM) were evaluated via response surface methodology and respective equations were calculated. The π-A isotherm determined in a Langmuir trough and the ELM and SAM parameters determined on the basis of this isotherm may be useful for determining the HLB of a fixed surfactant mixture. The RSM method used, in which ELM and SAM were assumed as two independent variables, can be a useful technique for tracking the influence of individual molecular characteristics on the hydrophilic-lipophilic properties of mixtures of surfactant compounds. Changes in HLB as a dependent variable can be described as a function of ELM and SAM.

A Study on the Effect of New Surfactant Proportions on the Recovery Improvement of Carbonate Reservoir

The strategy of integrating water injection and chemical additives in combining secondary and tertiary oil recovery techniques has been widely investigated in enhancing oil recovery efficiency. Nevertheless, there is a lack of sufficient evidence on the effectiveness of a mixture of cationic and nonionic surfactants combined with water injection techniques in enhancing recovery in the application of carbonate reservoirs. Therefore, it is particularly critical to explore the impact of this combination strategy in enhancing recovery in fractured carbonate reservoirs. The recovery enhancement effect can be assessed by conducting phase behavior experiments and determining interfacial tension and contact angle. Further, the effectiveness of specific surfactant ration solutions in enhancing recovery can be verified by performing drive-off experiments. The results show that low mineralization water and surfactants have a significant synergistic effect in enhancing the recovery efficiency of carbonate reservoirs, with the optimal ratio of cationic to non-ionic surfactants being 2.5:1. The optimized surfactant ratio is able to increase the recovery of carbonate reservoirs by 20% compared to the original recovery rate.

Finite size effects and optimization of the calculation of the surface tension in surfactant mixtures at liquid/vapour interfaces

The surface tension of monolayers with mixtures of anionic and nonionic surfactant at the liquid/vapour interface is studied. Previous works have observed that calculations of the surface tension of simple fluids show artificial oscillations for small interfacial areas, indicating that the surface tension data fluctuate due to the finite size effects and periodic boundary conditions. In the case of simulations of monolayers composed of surfactant mixtures, the surface tension not only oscillates for small areas but can also give non-physical data, such as negative values. Analysis of the monolayers with different surfactant mixtures, ionic (DTAB, CTAB, SDS) and nonionic (SB3-12), was done for density profiles, parameters of order and pair correlation functions for small and large box areas and all of them present similar behaviour. The fluctuations and the non-physical values of the surface tension are corrected when boxes with large interfacial areas are considered. The results indicate that in order to obtain reliable values of the surface tension, in computer simulations, it is important to choose not only the correct force field but also the appropriate size of the simulation box.

Volumetric properties of three nonylphenol ethoxylated nonionic surfactant mixtures with methanol: Experimental study and modeling with Tammann-Tait and PC-SAFT equation of state

Although physicochemical properties are essential for production and equipment design in oil and gas industries, there is still a lack of data for some systems because of hazardous temperature and pressure conditions. This work provides a volumetric behavior study of three different mixtures composed of nonylphenol ethoxylated nonionic surfactant (IGEPAL CO-520, CO-630, and CO-720) + methanol in the entire mole fraction composition range for temperatures from 313.15 K to 413.15 K and pressures up to 100.0 MPa. These systems behave as a regular liquid, with a volume contraction predominance. It was observed that for high methanol molar content, there is an increase in the cohesive forces because of the ethoxylated chain increases in oxyethylene units. Nevertheless, it was observed that the hydrogen bonds between ether oxygens and hydroxyl hydrogens decrease by increasing temperature, as given by internal pressure data and PC-SAFT modeling. Besides, a new set of parameters for the PC-SAFT equation of state is provided to calculate volumetric and second-order derivative properties.

Effect of electrolytes on the mechanism of clouding process and physico-chemical quantities of non-ionic surfactant and ciprofloxacin hydrochloride mixture

An investigation of the clouding behaviour of the aqueous solution of ciprofloxacin hydrochloride (CIPH) + Triton X-100 (TX-100) under different electrolytes media was performed by the phase-changing measurement method. The CP of the resultant mixture has been studied in aqueous solutions of some organic and inorganic salts (sodium carbonate (Na2CO3), sodium oxalate (NaOxa), sodium acetate (NaOAc) and magnesium sulphate (MgSO4)). The CP values of TX-100 (50 mmol kg−1) + CIPH (1 mmol kg−1) solution decreases in the presence of all electrolytes while the CP values satisfy the sequence: CP (aq. NaOAc) > CP (aq. MgSO4) > CP (aq. Na2CO3) > CP (aq. NaOxa). The decrease in the solubility of employed solution in the aq. electrolytes media was observed and obtained maximum solubility in aqueous NaOAc and minimum solubility in the aqueous NaOXa medium. The obtained positive Gibbs-free energy ( Δ G c 0 ) demonstrates the nonspontaneous nature of phase separation while the extent of nonspontaneity exhibits the reduction with enhancing electrolyte concentrations. The Δ H c 0 and Δ S c 0 values depict the existences of electrostatic and hydrophobic interactions between TX-100 and CIPH in aq. electrolytes solutions and the clouding process is enthalpy controlled. Entropy-enthalpy compensation variables were computed.

Influences of alcohols, urea and polyethylene glycol on the cloudy formation nature and physico-chemical parameters of the mixture of triton X-100 and ceftriaxone sodium salt

The phase separation of a nonionic surfactant (SFT), Triton X-100 (TX-100) and ceftriaxone sodium trihydrate (CTS) drug mixture was examined in the appearance of several alcohols (ethanol, 1-propanol, 2-propanol, 2-butanol) and hydrotropes (HDTs) (urea and polyethylene glycol (PEG)). The influences of changing composition and chain length of alcohols on the cloud points of aqueous TX-100 + CTS mixture were also assessed. The detected CP values were found to undergo an upsurge with the increased concentration of alcohols and HDTs. The computed ∆Gc0 values are acquired be positive in nature, demonstrating that the clouding of employed system was non-spontaneous in origin and the positive ∆Gc0 values were reduced with the growth of the contents of alcohols/HDTs. The obtained values of enthalpy (∆Hc0) and entropy (∆Sc0) were positive in magnitudes for most of the employed solvents with a few exceptions. The values of ∆Hc0 and ∆Sc0 were achieved as negative at lower contents of 2-butanol and highest content of urea/PEG. The enthalpy-entropy compensation variables (∆Hc0,*and Tc) associated with the clouding process of TX-100 + CTS mixture in aq. additive solutions were also calculated and interpreted in detailed way.

Effects of Different Types of Bile Salts on the Physical Properties of Ropinirole-Loaded

Background: Bilosomes are vesicular nanocarriers that contain bile salts, making them more flexible and resistant to degradation in the gastrointestinal tract. Objective: To evaluate the effect of two bile salts on the physical properties and stability of the ropinirole-loading bilosome. Methods: Sixteen bilosomal formulations were prepared by a reverse-phase evaporation method. Each formula includes a mixture of non-ionic surfactants (Span®60 and Tween®60), along with cholesterol and bile salts (either sodium taurocholate (STC) or sodium glycocholate (SGC). The characteristics of the bilosomal formulations (drug content, entrapment efficiency, vesicle size, polydispersity index, zeta potential, in-vitro drug release, and Fourier transform infrared spectroscopy) were evaluated. Results: The entrapment efficiency of ropinirole was reduced by using sodium glycocholate instead of sodium taurocholate. The vesicle size and zeta potential were also affected by the type of bile salt and its amount. Drug release profiles were sustained, indicating a good entrapment of ropinirole. The STC-containing bilosomes are more stable than the SGC-containing bilosomes. Bilosomal formula F5 showed the highest entrapment efficiency (64.82%), suitable vesicle size (179.8 nm), zeta potential (-9.162 mV), polydispersity index (0.5116), and in vitro drug release (62.33%) after 24 hr. Conclusion: Sodium taurocholate was more suitable for the preparation of ropinirole-loading bilosomes, with more stability of bilosomes in bile salt solution.

Effect of anionic and nonionic hydrotropes on the clouding behavior and thermodynamic properties of nonionic surfactant and ciprofloxacin hydrochloride drug mixture

In the present study, the cloudy development of nonionic triton X-100 (TX-100) and an antibiotic drug ciprofloxacin hydrochloride (CFH) mixture has been conducted by applying the cloud point (CP) measurements method. The CP of TX-100 + CFH mixture was examined in aqueous solutions of hydrotropes (HDTs) (sodium benzoate (NaBenz), sodium salicylate (NaSal), 4-amino benzoic (4-ABA), polyethylene glycol (PGE) and Caffeine (CAF)). The TX-100 and CFH concentration were conserved constant at 50 and 1 mmol kg−1 correspondingly throughout the investigation. The CP values of TX-100 + CFH solution were augmented in the existence of NaBenz, NaSal, CAF along with PEG but diminished in aq. 4-ABA solution; the effects were obtained to be augmented with the enhancing hydrotropes contents. The CP values for TX-100 + CFH mixture in aq. hydrotropes media follow the pattern: CP(aq.4-ABA)<CPaq.CAF≈CPaq.PEG<CPaq.NaBenz<CPaq.NaSal. Therefore, the solubility of TX-100 + CFH mixture is achieved to be decreased in aq. solutions of 4-ABA while the solubility experienced an enhancement in aq. NaSal, NaBenz, PEG and CAF solutions. Among hydrotropes used in the present study, NaSal is the most effective solubility enhancer. The free energy (ΔGc0) were achieved to be positive in all the solvent media used in the study which exposes that the cloudy development process isnot spontaneous. The enthalpy (ΔHc0) and the entropy (ΔSc0) of clouding were obtained to be positive in hydrotropes media. The ΔHc0 and ΔSc0 values imply that the main forces of the cloudy formation in TX-100 and CFH system are hydrophobic interaction, hydrogen bonding, and electrostatic interactions. The compensation temperature (Tc) along with the intrinsic enthalpy gain (ΔHc0,∗) were also calculated and discussed. It is probable that the knowledge gained from these types of studies will be quite helpful in both pharmaceutics formulations and drug delivery system.

Continuous Electrophoretic Separation of Charged Dyes in Liquid Foam

A novel electrophoretic separation technique is presented, where continuous electrophoretic separation is demonstrated using free flowing liquid foams. Continuous foam electrophoresis combines the principle of capillary electrophoresis and interactions between analytes and the electrical double layer, with the ability of Free Flow Electrophoresis to continuously separate and recover analytes automatically. A liquid foam is used to provide a network of deformable micro and nano channels with a high surface area, presenting a novel platform for electrophoresis, where interfacial phenomena could be exploited to modify analyte migration. The main purpose of this paper is to present a proof-of-concept study and provide fundamental understanding of a complex foam system in continuous separation mode, i.e., flowing liquid foam under an external electric field with electrophoresis and chemical reactions at the electrodes continuously changing the system. Liquid foam is generated using a mixture of anionic and non-ionic surfactants and pumped through a microfluidic separation chamber between two electrodes. The effectiveness of the device is demonstrated using a dye mixture containing a neutral dye and an anionic dye. At the outlet, the foam is separated and collected into five fractions which are individually probed for the concentration of the two dyes used. The anionic dye was concentrated up to 1.75 (±0.05) times the initial concentration in a select outlet, while the neutral dye concentration remained unchanged in all outlets, demonstrating the potential for electrophoretic foam separations.

Synergistic effect of binary mixture of anionic nonionic surfactant on inhibiting coal dust pollution: Experiment and simulation

Coal dust is a pollutant particle generated during the process of coal development and utilization. It can cause damage to the surrounding environment and human health. In this paper, experimental and molecular dynamics simulations were used to select four surfactants: fatty alcohol polyoxyethylene ether sodium sulfate (AES), sodium dodecyl benzene sulfonate (SDBS), lauryl glucoside (APG-12), and fatty alcohol polyoxyethylene ether (AEO-9). The wettability and adsorption ability of a single surfactant and a combination of surfactants were studied at the macro and micro levels, Laying a foundation for the preparation of binary surfactants. The results show that the anionic nonionic binary composite aqueous solution of 0.07% SDBS and 0.05% AEO-9 can greatly increase the content of hydrophilic functional groups in coal molecules, and its hydrophobic groups can be firmly adsorbed on the pore size of coal dust, effectively solving the problem of poor hydrophilicity and difficult wetting of coal dust. In addition, on the basis of quantitative characterization of micromolecules and macro wetting test, research on foam characteristics has been added to further improve dust suppression efficiency and effectively control air pollution caused by coal mining and use.

Mitigating the skin irritation potential of mixtures of anionic and non-ionic surfactants by incorporating low-toxicity silica nanoparticles

There has been a notable upswing in the adoption of product formulations based on nanotechnology within the cosmetics industry. By using nanocarriers, such as solid or micellar nanoparticles, the quality and performance of cosmetics can be improved, allowing for better transport of bioactive components into the skin. However, it is important to note that the interaction between these compounds may lead to skin irritation. To mitigate skin irritability, nano-formulation strategies should be implemented in cosmetics. A proof-of-concept study was therefore conducted to investigate if low-toxicity nanoparticles (silica) could be used in combination with a mixture of anionic surfactants and a low-irritant cosurfactant (non-ionic) to develop safer cosmetic formulations that reduce skin damage. The skin irritation potential of the formulations was assessed in vitro using the well-known Zein method.As anticipated, non-ionic surfactants pose the lowest risk for skin irritation. When compared to single anionic surfactants, non-ionic/anionic mixtures were found to decrease skin irritability by 24–67 %. However, when silica nanoparticles (NPs) were added to single surfactants, the potential for skin irritation increased, particularly when the anionic surfactant molecules were arranged in a spherical core-shell structure around the surface of the NPs. On the other hand, incorporating NPs in surfactant mixtures enhanced their formulation stability. While all three-component formulations were found to decrease skin irritability, those that formed spherical core-shell structures demonstrated the most significant reduction, likely related to a reduction in charge density caused by the non-ionic surfactant which may decrease protein solubilisation. Therefore, the inclusion of silica NPs can potentially result in a further reduction of the skin irritation potential caused by mixtures of anionic and non-ionic surfactants.

Impacts of several salts on the clouding development, nature of interactions and associated physico-chemical variables of mixture of promethazine hydrochloride and conventional nonionic surfactant

Herein, in the presence of electrolytes, the cloud points (CPs) of the mixture of a conventional uncharged amphiphile (triton X-100 (TX-100)) and promethazine hydrochloride (PMH; phenothiazine medicine) were measured and explained in great details. The CP values of the employed surfactant + PMH system were reduced with enhancing salts contents (NaCl, Na2SO4, NH4Cl, and (NH4)2SO4)), while the CP values of the study system followed the trend: Na2SO4 < NaCl and (NH4)2SO4 < NH4Cl. The different thermodynamic parameters of phase separation, including standard free energy (ΔG 0 c), enthalpy (ΔH 0 c), and entropy (ΔS 0 c) changes were also calculated and discussed elaborately. The values of free energy change (ΔG 0 c) were obtained to be positive, indicating that the clouding phenomena are non-spontaneous. Different transfer properties (free energy (ΔG 0 c.t), enthalpy (ΔH 0 c,t ), and entropy (ΔS 0 c,t ) of transfer), intrinsic enthalpy gain (ΔH 0,*c) and compensation temperature (T c) of the inspected system have also been assessed and discussed.

Aqueous solutions of non-ionic surfactant mixtures as mediums for green extraction of polyphenols from red grape pomace

Grapevine production is predominantly oriented towards winemaking, consequently generating large amount of polyphenol-rich waste. Micellar solutions of surfactants are recognized for their ability to efficiently solubilize compounds from different plant material. This study examined potential of water solutions of mixtures of non-ionic surfactants Brij S20 (BS20) and poloxamer 407 (P407) for the extraction of polyphenols from red grape pomace. Critical micelle concentrations of extraction mediums (mixtures of BS20/P407 1:1, 1:9 and 9:1) were determined. Total phenolic content, individual phenolic profile and antioxidant capacity of extracts were examined. Measurement of hydrodynamic radii of micelles before and after extraction was performed. Water, water:ethanol (1:1) and pure BS20 and P407 extracts were used for comparison. Values of experimental critical micelle concentrations decreased with decreasing mole fraction of P407 and synergistic interactions between components of mixed micelles were observed. Total phenolic contents of BS20/P407 (9:1) and (1:1) extracts were 54.49 ± 0.12 and 54.73 ± 0.26 mg GAE/g DW, respectively, and these values are up to 19% higher than those obtained with pure surfactants. The most pronounced increase in solubilization efficiency in mixed micelles (BS20/P407 (1:1) and (9:1)) was observed for less polar compounds (e.g., quercetin, kaempferol and rutin) compared to a single-surfactant-micelles. All investigated systems showed an increase in micelle size after extraction. The present study has demonstrated green method for extraction of polyphenols from grape pomace with assistance of water solutions of non-ionic surfactant mixtures, which could be useful for further practical applications.

On the relationship between the properties of planar structures of non-ionic surfactants and their vesicular analogues – Niosomes

In recent years, the study of niosomes as nanocarriers alternative to liposomes has received increasing attention. In contrast to well-studied liposome membranes, many aspects of the behavior of analogous niosome bilayers have not been studied. This paper considers one of these aspects related to the communication between the physicochemical properties of planar and vesicular objects. We present the first results of comparative studies of Langmuir monolayers of binary and ternary (with cholesterol) mixtures of non-ionic surfactants based on sorbitan esters and niosomal structures assembled from the same materials. The Thin-Film Hydration (TFH) method in the gentle shaking version was used to produce the particles of large sizes, while small unilamellar high quality vesicles with a unimodal distribution of particles were prepared by TFH using ultrasonic treatment and extrusion. An analysis of the structural organization and phase state of monolayers based on compression isotherms and supplemented by thermodynamic calculations, as well as the results of determining the particle morphology, polarity and microviscosity of niosome shells, made it possible to obtain fundamental data on the intermolecular interactions of the components and their packing in shells and to relate these data to the properties of niosomes. This relationship can be used to optimize the composition of niosome membranes and predict the behavior of these vesicular systems. It was shown that cholesterol excess creates regions of bilayers with increased rigidity (like “lipid rafts”), which hinders the process of folding film fragments into small niosomes.

Observation of Strong Synergy in the Interfacial Water Response of Binary Ionic and Nonionic Surfactant Mixtures.

Interfacial vibrational footprints of the binary mixture of sodium dodecyl sulfate (SDS) and hexaethylene glycol monododecyl ether (C12E6) were probed using heterodyne detected vibrational sum frequency generation (HDVSFG). Our results show that in the presence of C12E6 at CMC (70 μM) the effect of SDS on the orientation of interfacial water molecules is enhanced 10 times compared to just pure surfactants. The experimental results contest the traditional Langmuir adsorption model predictions. This is also evidenced by our molecular dynamics simulations that show a remarkable restructuring and enhanced orientation of the interfacial water molecules upon DS- adsorption to the C12E6 surface. The simulations show that the adsorption free energy of DS- ions to a water surface covered with C12E6 is an enthalpy-driven process and more attractive by ∼10 kBT compared to the adsorption energy of DS- to the surface of pure water.

Modelling the partitioning equilibria of nonionic surfactant mixtures within the HLD framework

Commercial non-ionic surfactants are usually blends of species differing in the degree of ethoxylation, characterised by a distribution of surfactants with different affinity for the oil and the aqueous phases. This leads to an unexpected concentration dependence of the phase behaviour and the rationalization of such deviations is necessary for their exploitation in surfactant-based formulations. In this work, the phase behaviour of commercial Novel® nonionic surfactants in presence of brine and oil was studied fixing equal volumes of organic and aqueous phases and changing the amount of surfactant and brine salinity (fish cut). The conditions for the balanced state (microemulsion solubilizing equals amount of water and oil) have been determined for different alkanes. The phase behaviour of the surfactant mixture was described, without a priori information about its actual chemical composition, in terms of two pseudo-components: one hydrophilic, entirely at the interface, and the other lipophilic, able to partition itself between the interface and the oil bulk according to a partition constant P. The pseudo-components effect on the interface is quantified through surfactant characteristic parameters (SCPs), according to the Hydrophilic-Lipophilic-Difference (HLD) model. SCPs and P can be experimentally determined by fitting the dependence of the balanced state on the surfactant concentration. The model is successfully applied to the tested surfactants and can quantitively predict the behaviour of their mixtures.

PHARMACEUTICAL NIOSOMES DRUG DELIVERY: A COMPLETE REVIEW OF NEW DELIVERY SYSTEM

Over the past ten years, people working in the field of drug delivery systems have become increasingly interested in designing vesicles as a tool to improve drug delivery. A hydrating mixture of cholesterol and nonionic surfactants forms niosomes, which are vesicles. Liposomes, microspheres, engineering science,small emulsions, antibody loaded drug delivery , magnetic microcapsules,implantable pumps, and niosomes are just a few of the unique methods employed to administer these medications. There are two requirements before designing and developing a novel drug delivery system (NDDS). It must first spread the medication at a preset rate and then release an amount of medication at the site of action that is therapeutically efficacious. These requirements cannot be satisfied by conventional dose forms. In essence, niosomes are non-ionic surfactant-based vesicles in which a group of surfactant macromolecules forms a bilayer to form a membrane that entirely seals off an aqueous solution of solute. Targeted medication delivery is made possible by the reasonable circulation persistence of niosomes. An overview of niosome preparation techniques, niosome kinds, characterisation, and applications is also included in this paper.&#x0D; &#x0D; Due to qualities including improved drug penetration, local depot for continuous drug release, and a rate-limiting membrane for modulating systemic absorption of pharmaceuticals via the skin, niosomes, vesicular nanocarriers, are gaining a lot of attention as prospective transdermal drug delivery systems. There are a number of theories put up to explain why niosomes can improve medication transfer through the skin. This review aims to provide an exhaustive collection of recent studies in this fascinating field, with special emphasis on the methods used to maximise the potential of niosomes. Niosomal carriers are suitable for the transdermal delivery of a variety of pharmacological agents, including antioxidant, anticancer, anti-inflammatory, antimicrobial, and antibacterial molecules.

Microemulsion and interfacial properties of anionic/nonionic surfactant mixtures based on sulfonate surfactants: The influence of alcohol

The influence of alcohols on the microemulsion and interfacial properties of sulfonate and nonionic surfactant mixtures (LAS-IPA/AEO9 mixture) were explored. Surface properties and interaction parameters were investigated to determine the optimum molar ratio of the LAS-IPA to AEO9, and the subsequent experimental studies in this paper were based on the system of mixtures (nLAS-IPA: nAEO9 (4:6)). The microemulsion phase behaviors of LAS-IPA / AEO9 / alcohol / n-decane / water were investigated by constructing a pseudo-ternary phase diagram. Results suggest that the microemulsion systems with n-butanol and n-pentanol as cosurfactants behave have optimal solubilization capacity when the corresponding alcohol to mixed surfactant (Km value) mass ratios are 1:1 and 1:1 ∼ 1:2, respectively. The solubilization capacity of the two systems reached their maximum in the temperature range of 35 °C–40 °C. The hydrodynamic diameters of microemulsion were determined by employing dynamic light scattering (DLS), and the average hydrodynamic diameters of microemulsion increased with the carbon number of alcohol, which ranges from 12 nm to 21 nm. Moreover, the equilibrium oil–water interfacial tension, the dynamic adsorption mechanism, and the dilational viscoelasticity of the oil–water interfacial film were studied using spinning-drop method and drop shape analysis, respectively. The results shows that equilibrium oil–water interfacial tension decreased with increased carbon number of the regular alcohol in the system. However, the decrease of interfacial tension with decreased Km is not significant when the carbon numbers of regular alcohol are 5 and 6. At the initial stage, diffusion-controlled adsorption processes were followed with n-propanol and n-butanol as cosurfactants when the Km values were 1:2, but systems of the other two cosurfactants yielded mixed kinetics-diffusion control. The dilatational modulus of oil–water interfacial film increased with the carbon number increase in regular alcohol or the decreased Km value. The contact angles of n-butanol based microemulsion system at the hydrophilic interface and the lipophilic interface reached 20° and 18°, which had excellent bi-phasic wettability property. At the same time, the oil film removal efficiency of the n-butanol based microemulsion was the highest, which was close to 100 % at 24 h.

The packing parameter of bare surfactant does not necessarily indicate morphological changes

Morphological changes of surfactant in water are believed to rely on the packing parameter of individual molecules. However, its validity has not been well examined due to the difficulties in both experiments and simulations. Herein, we perform all-atom molecular dynamics simulations, combined with the heavy hydrogen atom method, for aqueous mixtures of non-ionic surfactant, pentaethylene glycol monododecyl ether. We demonstrate the spontaneous self-reorganization from hexagonal to lamellar phase and quantify the variation of the packing parameter, hydration manner, and thermodynamic components during the process. The results clearly show that the packing parameter of bare surfactant is almost identical between these phases; thus, it does not function as an indicator. Instead, the consideration of hydration shell is likely to be necessary to account for the effective head group. We also find that the water molecules disturbed by surfactant aggregates are depleted during the hexagonal-to-lamellar transformation and subsequently correlate the dehydration to an increase in surfactant-related entropy, which is the dominant thermodynamic factor for the morphological transformation.

Lactoperoxidase partitioning from whey using the reverse micelles of non‐ionic/ionic mixed surfactants: Improvement of back extraction

The reverse micellar system formed with a mixture of ionic and non-ionic surfactants, AOT (Sodium bis(2-ethyl hexyl) sulfosuccinate)/ Tween 80 in isooctane, was studied for the selective extraction of Bovine Lactoperoxidase (LP) from acid whey. The effect of pH and ionic strength of acid whey and surfactant concentrations were studied and a maximum of 86% LP was extracted from acid whey at pH 9.5 with the addition of 0.2M KCl to the reverse micelles formed with AOT (115 mM) / Tween 80 (23 mM). The back extraction of LP was studied at different aqueous stripping phase pH, ionic strength and concentration of counter-ionic surfactant CTAB (Cetyltrimethylammonium bromide). The back extraction of 112% with 80% LP recovery was achieved when the stripping phase pH was 10.5 with 1.5 M KCl and 60 mM CTAB. The antimicrobial activity of the extracted LP showed reduction in colony forming units of S. aureus.