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17 pages, 2050 KiB

Open AccessArticle

Cholesteryl Phenolipids as Potential Biomembrane Antioxidants

by Vânia Costa, Marlene Costa, Francisca Arques, Mariana Ferreira, Paula Gameiro, Dulce Geraldo, Luís S. Monteiro and Fátima Paiva-Martins

Molecules 2024, 29(20), 4959; https://doi.org/10.3390/molecules29204959 - 20 Oct 2024

Viewed by 569

Abstract

The lipophilization of polyphenols (phenolipids) may increase their affinity for membranes, leading to better antioxidant protection. Cholesteryl esters of caffeic, dihydrocaffeic, homoprotocatechuic and protocatechuic acids were synthetized in a one-step procedure with good to excellent yields of ~50–95%. After evaluation of their radical [...] Read more.

The lipophilization of polyphenols (phenolipids) may increase their affinity for membranes, leading to better antioxidant protection. Cholesteryl esters of caffeic, dihydrocaffeic, homoprotocatechuic and protocatechuic acids were synthetized in a one-step procedure with good to excellent yields of ~50–95%. After evaluation of their radical scavenging capacity by the DPPH method and establishing the anodic peak potential by cyclic voltammetry, their antioxidant capacity against AAPH-induced oxidative stress in soybean PC liposomes was determined. Their interaction with the liposomal membrane was studied with the aid of three fluorescence probes located at different depths in the membrane. The cholesteryl esters showed a better or similar radical scavenging capacity to that of α-tocopherol and a lower anodic peak potential than the corresponding parental phenolic acids. Cholesteryl esters were able to protect liposomes to a similar or greater extent than α-tocopherol. However, despite their antiradical capacity and being able to penetrate and orientate in the membrane in a parallel position to phospholipids, the antioxidant efficiency of cholesteryl esters was deeply dependent on the phenolipid polyphenolic moiety structure. When incorporated during liposome preparation, cholesteryl protocatechuate and caffeate showed more than double the activity of α-tocopherol. Thus, cholesteryl phenolipids may protect biomembranes against oxidative stress to a greater extent than α-tocopherol. Full article

(This article belongs to the Special Issue Research Progress of Surfactants)

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14 pages, 4032 KiB

Open AccessArticle

Synthesis and Kinetics of CO₂-Responsive Gemini Surfactants

by Yao Li, Xinyu Tang, Pujiang Yang, Yuhui Zhang and Jinhe Liu

Molecules 2024, 29(17), 4166; https://doi.org/10.3390/molecules29174166 - 3 Sep 2024

Viewed by 795

Abstract

Surfactants are hailed as “industrial monosodium glutamate”, and are widely used as emulsifiers, demulsifiers, water treatment agents, etc., in the petroleum industry. However, due to the unidirectivity of conventional surfactants, the difficulty in demulsifying petroleum emulsions generated after emulsification with such surfactants increases [...] Read more.

Surfactants are hailed as “industrial monosodium glutamate”, and are widely used as emulsifiers, demulsifiers, water treatment agents, etc., in the petroleum industry. However, due to the unidirectivity of conventional surfactants, the difficulty in demulsifying petroleum emulsions generated after emulsification with such surfactants increases sharply. Therefore, it is of great significance and application value to design and develop a novel switchable surfactant for oil exploitation. In this study, a CO₂-switchable Gemini surfactant of N,N′-dimethyl-N,N′-didodecyl butylene diamine (DMDBA) was synthesized from 1, 4-dibromobutane, dodecylamine, formic acid, and formaldehyde. Then, the synthesized surfactant was structurally characterized by infrared (IR) spectroscopy, hydrogen nuclear magnetic resonance (¹H NMR) spectroscopy, and electrospray ionization mass spectrometry (ESI-MS); the changes in conductivity and Zeta potential of DMDBA before and after CO₂/N₂ injection were also studied. The results show that DMDBA had a good CO₂ response and cycle reversibility. The critical micelle concentration (CMC) of cationic surfactant obtained from DMDBA by injecting CO₂ was 1.45 × 10⁻⁴ mol/L, the surface tension at CMC was 33.4 mN·m⁻¹, and the contact angle with paraffin was less than 90°, indicating that it had a good surface activity and wettability. In addition, the kinetic law of the process of producing surfactant by injecting CO₂ was studied, and it was found that the process was a second-order reaction. The influence of temperature and gas velocity on the reaction dynamics was explored. The calculated values from the equation were in good agreement with the measured values, with a correlation coefficient greater than 0.9950. The activation energy measured during the formation of surfactant was Ea = 91.16 kJ/mol. Full article

(This article belongs to the Special Issue Research Progress of Surfactants)

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13 pages, 775 KiB

Open AccessArticle

Measuring the Equilibrium Spreading Pressure—A Tale of Three Amphiphiles

by Boyan Peychev, Dimitrinka Arabadzhieva, Ivan L. Minkov, Iglika M. Dimitrova, Elena Mileva, Stoyan K. Smoukov and Radomir I. Slavchov

Molecules 2024, 29(17), 4004; https://doi.org/10.3390/molecules29174004 - 24 Aug 2024

Viewed by 648

Abstract

A surfactant’s equilibrium spreading pressure (ESP) is the maximum decrease in surface tension achievable at equilibrium below the Krafft point. Difficulties in measuring the ESP have been noted previously but no well-established experimental protocols to overcome them exist. We present a case study [...] Read more.

A surfactant’s equilibrium spreading pressure (ESP) is the maximum decrease in surface tension achievable at equilibrium below the Krafft point. Difficulties in measuring the ESP have been noted previously but no well-established experimental protocols to overcome them exist. We present a case study of three solid amphiphiles with different propensities to spread on the air–water interface. Starting with the partially water soluble n-dodecanol (C₁₂H₂₅OH), which spreads instantaneously. The strong Marangoni flows associated with the spreading result in the dislocating of the Wilhelmy plate or crystals attaching to it. A temporary mechanical barrier in front of the spreading crystals mitigates the flows disturbing the plate. Presaturating the subphase with the amphiphile prevents the establishment of dynamic steady states, reduces the standard error by a factor of three and causes faster equilibration. The perfluoroalkylated analog of dodecanol (11:1 fluorotelomer alcohol, C₁₁F₂₃CH₂OH) is slow spreading. With surfactant crystals on the interface, the surface pressure reaches a pre-equilibrium plateau within an hour, followed by equilibration on day-long timescales. We show that it is better to estimate the ESP by averaging the values of multiple pre-equilibrium plateaus rather than waiting for equilibrium to be established. Finally, the nonspreading amphiphile DPPC exhibits a large barrier for the mass transfer from the DPPC crystal to the aqueous surface. This was overcome by introducing a volatile, water-immiscible solvent deposited on the surface next to the crystals to facilitate the spreading process and leave behind a monolayer. Full article

(This article belongs to the Special Issue Research Progress of Surfactants)

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15 pages, 1608 KiB

Open AccessArticle

The Salt-Induced Diffusiophoresis of Nonionic Micelles—Does the Salt-Induced Growth of Micelles Influence Diffusiophoresis?

by Onofrio Annunziata

Molecules 2024, 29(15), 3618; https://doi.org/10.3390/molecules29153618 - 31 Jul 2024

Viewed by 795

Abstract

Salt-induced diffusiophoresis is the migration of a colloidal particle in water due to a directional salt concentration gradient. An important example of colloidal particles is represented by micelles, generated by surfactant self-assembly in water. For non-ionic surfactants containing polyethylene glycol (PEG) groups, PEG [...] Read more.

Salt-induced diffusiophoresis is the migration of a colloidal particle in water due to a directional salt concentration gradient. An important example of colloidal particles is represented by micelles, generated by surfactant self-assembly in water. For non-ionic surfactants containing polyethylene glycol (PEG) groups, PEG preferential hydration at the micelle–water interface is expected to drive micelle diffusiophoresis from high to low salt concentration. However, micelles are reversible supramolecular assemblies, with salts being able to promote a significant change in micelle size. This phenomenon complicates the description of diffusiophoresis. Specifically, it is not clear to what extent the salt-induced growth of micelles affects micelle diffusiophoresis. In this paper, a multiple-equilibrium model is developed for assessing the contribution of the micelle growth and preferential hydration mechanisms to the diffusiophoresis of non-ionic micelles. The available experimental data characterizing the effect of NaCl on Triton X-100 aggregation number are combined with data on diffusiophoresis and the preferential hydration of PEG chains to show that the contribution of the micelle growth mechanism to overall diffusiophoresis is small compared to that of preferential hydration. Full article

(This article belongs to the Special Issue Research Progress of Surfactants)

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16 pages, 10772 KiB

Open AccessArticle

Study on the Synthesis, Surface Activity, and Self-Assembly Behavior of Anionic Non-Ionic Gemini Surfactants

by Zhiqiang Man and Wenxiang Wu

Molecules 2024, 29(8), 1725; https://doi.org/10.3390/molecules29081725 - 11 Apr 2024

Cited by 3 | Viewed by 1164

Abstract

The use of surfactants in oil recovery can effectively improve crude oil recovery rate. Due to the enhanced salt and temperature resistance of surfactant molecules by non-ionic chain segments, anionic groups have good emulsifying stability. Currently, there are many studies on anionic non-ionic [...] Read more.

The use of surfactants in oil recovery can effectively improve crude oil recovery rate. Due to the enhanced salt and temperature resistance of surfactant molecules by non-ionic chain segments, anionic groups have good emulsifying stability. Currently, there are many studies on anionic non-ionic surfactants for oil recovery in China, but there is relatively little systematic research on introducing EOs into hydrophobic alkyl chains, especially on their self-assembly behavior. This article proposes a simple and effective synthesis method, using 3-aminopropane sulfonic acid, fatty alcohol polyoxyethylene ether, and epichlorohydrin as raw materials, to insert EO into hydrophobic alkyl chains and synthesize a series of new anionic non-ionic Gemini surfactants (CnEO-5, n = 8, 12, 16). The surface activity, thermodynamic properties, and self-assembly behavior of these surfactants were systematically studied through surface tension, conductivity, steady-state fluorescence probes, transmission electron microscopy, and molecular dynamics simulations. The surface tension test results show that CnEO-5 has high surface activity and is higher than traditional single chain surfactants and structurally similar anionic non-ionic Gemini surfactants. Additionally, thermodynamic parameters (e.g., ΔG°_mic ΔH°_mic ΔS°_mic et al. indicate that CnEO-5 molecules are exothermic and spontaneous during the micellization process. DLS, p-values, and TEM results indicate that anionic non-ionic Gemini surfactants with shorter hydrophobic chains (such as C8EO-5) tend to form larger vesicles in aqueous solutions, which are formed in a tail to tail and staggered manner; Negative non-ionic Gemini surfactants with longer hydrophobic chains (such as C12EO-5, C16EO-5) tend to form small micelles. The test results indicate that CnEO-5 anionic non-ionic Gemini surfactants have certain application prospects in improving crude oil recovery. Full article

(This article belongs to the Special Issue Research Progress of Surfactants)

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11 pages, 2320 KiB

Open AccessCommunication

Solubilization of Phospholipid by Surfactin Leading to Lipid Nanodisc and Fibrous Architecture Formation

by Tomohiro Imura, Satohiro Yanagisawa, Yuri Ikeda, Ryodai Moriyama, Kenichi Sakai, Hideki Sakai and Toshiaki Taira

Molecules 2024, 29(6), 1300; https://doi.org/10.3390/molecules29061300 - 14 Mar 2024

Cited by 2 | Viewed by 1283

Abstract

Nanodiscs belong to a category of water-soluble lipid bilayer nanoparticles. In vivo nanodisc platforms are useful for studying isolated membrane proteins in their native lipid environment. Thus, the development of a practical method for nanodisc reconstruction has garnered consider-able research interest. This paper [...] Read more.

Nanodiscs belong to a category of water-soluble lipid bilayer nanoparticles. In vivo nanodisc platforms are useful for studying isolated membrane proteins in their native lipid environment. Thus, the development of a practical method for nanodisc reconstruction has garnered consider-able research interest. This paper reports the self-assembly of a mixture of bio-derived cyclic peptide, surfactin (SF), and l-α-dimyristoylphosphatidylcholine (DMPC). We found that SF induced the solubilization of DMPC multilamellar vesicles to form their nanodiscs, which was confirmed by size-exclusion chromatography, dynamic light scattering, and transmission electron microscopy analyses. Owing to its amphiphilic nature, the self-assembled structure prevents the exposure of the hydrophobic lipid core to aqueous media, thus embedding ubiquinol (CoQ10) as a hydrophobic model compound within the inner region of the nanodiscs. These results highlight the feasibility of preparing nanodiscs without the need for laborious procedures, thereby showcasing their potential to serve as promising carriers for membrane proteins and various organic compounds. Additionally, the regulated self-assembly of the DMPC/SF mixture led to the formation of fibrous architectures. These results show the potential of this mixture to function as a nanoscale membrane surface for investigating molecular recognition events. Full article

(This article belongs to the Special Issue Research Progress of Surfactants)

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15 pages, 6340 KiB

Open AccessArticle

Stripping Mechanism of Surfactant System Based on Residual Oil on the Surface of Sand-Conglomerate Rocks with Different Grain Size Mineral Compositions

by Yuanyuan Wang, Daigang Wang, Chao Ding, Jing Li and Shengdong Jiang

Molecules 2024, 29(6), 1278; https://doi.org/10.3390/molecules29061278 - 13 Mar 2024

Viewed by 900

Abstract

During the development of a sand-conglomerate reservoir, there is a huge variation in rock grain size and different åmineral compositions of different-sized sand grains. The mineral composition and microstructure of the rock both have an impact on the characteristics of the remaining oil [...] Read more.

During the development of a sand-conglomerate reservoir, there is a huge variation in rock grain size and different åmineral compositions of different-sized sand grains. The mineral composition and microstructure of the rock both have an impact on the characteristics of the remaining oil in the reservoir. The stripping mechanism of a surfactant system on sand-conglomerate surface crude oil with varied grain size minerals was explored in this paper. Sand-conglomerate was classified and analyzed to determine their wettability and stripping oil effects. The optimization of the surfactant solution system and molecular dynamics simulation revealed the surfactant stripping mechanism on crude oil on distinct sandstone minerals. The results of the study showed that montmorillonite minerals are more readily adsorbed by surfactants. The crude oil within them is more likely to compete for adsorption and to be stripped off, and then extracted with the recovery fluid. The surfactant solution system can increase the hydrophilicity of the rock surface, make the crude oil on the rock surface shrink and gather, and enhance the transportation ability of the displacement fluid. And the emulsification seals part of the pore in the reservoir, increases the displacement pressure, and improves the overall wave volume. The results of this paper are of great significance for the efficient development of sand-conglomerate reservoirs. Full article

(This article belongs to the Special Issue Research Progress of Surfactants)

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13 pages, 6013 KiB

Open AccessArticle

The Effect of Crude Oil Stripped by Surfactant Action and Fluid Free Motion Characteristics in Porous Medium

by Qingchao Cheng, Guangsheng Cao, Yujie Bai and Ying Liu

Molecules 2024, 29(2), 288; https://doi.org/10.3390/molecules29020288 - 5 Jan 2024

Cited by 3 | Viewed by 1070

Abstract

The surfactant solution is crucial in facilitating the spontaneous imbibition process for the recovery of oil in tight reservoirs. Further investigation is required to examine the fluid flow in porous mediums and the process of crude oil stripping by a surfactant solution during [...] Read more.

The surfactant solution is crucial in facilitating the spontaneous imbibition process for the recovery of oil in tight reservoirs. Further investigation is required to examine the fluid flow in porous mediums and the process of crude oil stripping by a surfactant solution during spontaneous imbibition. Hence, this study aims to determine the free motion properties of oil and water in porous mediums using the finite-element approach to solve the multiphase flow differential equation, taking into account the capillary pressure. An investigation was conducted to examine the impact of oil viscosity and interfacial tension on the mean liquid flow rate and oil volume fraction. An experimental study was conducted to investigate the impact of surface tension, interfacial tension, and wetting angle on crude-oil-stripping efficiency. The findings indicate that the stripped crude oil migrated through porous mediums as individual oil droplets, exhibiting a degree of stochasticity in its motion. When the interfacial tension is reduced, the average velocity of the fluid in the system decreases. The crude oil exhibited a low viscosity, high flow capacity, and a high average flow rate within the system. Once the concentration of the surfactant solution surpasses a specific threshold, it binds with the oil to create colloidal aggregates, resulting in the formation of micelles and influencing the efficiency of the stripping process. As the temperature rises, the oil-stripping efficiency also increases. Simultaneously, an optimal range of wetting angle, surface tension, and interfacial tension could enhance the effectiveness of removing oil using surfactant solutions. The research results of this paper enrich the enhanced oil recovery mechanism of surfactant and are of great significance to the development of tight reservoirs. Full article

(This article belongs to the Special Issue Research Progress of Surfactants)

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14 pages, 3172 KiB

Open AccessArticle

Effect of Gas Composition on Surfactant Injectivity in a Surfactant-Alternating-Gas Foam Process

by Jiakun Gong, Yuan Wang, Raj Deo Tewari, Ridhwan-Zhafri B. Kamarul Bahrim and William Rossen

Molecules 2024, 29(1), 100; https://doi.org/10.3390/molecules29010100 - 22 Dec 2023

Cited by 2 | Viewed by 1182

Abstract

Aqueous foam is a dispersion of gas in liquid, where the liquid acts as the continuous phase and the gas is separated by thin liquid films stabilized by a surfactant. Foam injection is a widely used technique in various applications, including CO₂ [...] Read more.

Aqueous foam is a dispersion of gas in liquid, where the liquid acts as the continuous phase and the gas is separated by thin liquid films stabilized by a surfactant. Foam injection is a widely used technique in various applications, including CO₂ sequestration, enhanced oil recovery, soil remediation, etc. Surfactant-alternating-gas (SAG) is a preferred approach for foam injection, and injectivity plays a vital role in determining the efficiency of the SAG process. Different gases can be applied depending on the process requirements and availability. However, the underlying mechanisms by which gas composition impacts injectivity are not yet fully understood. In this work, the effect of gas composition on fluid behavior and injectivity in a SAG process was investigated using three gases: N₂, CO₂, and Kr. Our observations revealed that gas solubility in liquid was key for the formation and evolution of liquid fingers, and therefore was very important for liquid injectivity. A lower gas solubility in liquid led to a slower increase in surfactant solution injectivity. In addition, the development of surfactant solution injectivity took significantly longer when the surfactant solution was partially pre-saturated compared to when it was unsaturated. Additionally, the propagation of the collapsed-foam bank during gas injection was accelerated when the gas had a greater solubility in water. Full article

(This article belongs to the Special Issue Research Progress of Surfactants)

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14 pages, 3982 KiB

Open AccessArticle

Probing the Demulsification Mechanism of Emulsion with SPAN Series Based on the Effect of Solid Phase Particles

by Qingchao Cheng, Guangsheng Cao, Yujie Bai, Zhixuan Zhu, Ning Zhang and Dongju Li

Molecules 2023, 28(7), 3261; https://doi.org/10.3390/molecules28073261 - 6 Apr 2023

Cited by 26 | Viewed by 2181

Abstract

The solid particles in the produced fluids from the oil wells treated by compound flooding can greatly stabilize the strength of the interfacial film and enhance the stability of the emulsion, increasing the difficulty of processing these produced fluids on the ground. In [...] Read more.

The solid particles in the produced fluids from the oil wells treated by compound flooding can greatly stabilize the strength of the interfacial film and enhance the stability of the emulsion, increasing the difficulty of processing these produced fluids on the ground. In this paper, the oil phase and the water phase were separated from the SPAN series emulsions by electrical dehydration technology and adding demulsifier agents. The changing trends of the current at both ends of the electrodes were recorded during the process. The efficient demulsification of the emulsion containing solid particles was studied from the perspective of oil-water separation mechanisms. Combined with the method of molecular dynamics simulation, the effect of the addition of a demulsifier on the free movement characteristics of crude oil molecules at the position of the liquid film of the emulsion were further analyzed. The results indicated that the presence of solid particles greatly increased the emulsifying ability of the emulsion and reduced its size. Under the synergistic effect of demulsifier and electric dehydration, the demulsification effect of the emulsion increased significantly, and the demulsification rate could reach more than 82%. The addition of demulsifiers changed the stable surface state of the solid particles. The free movement ability of the surrounding crude oil molecules was enhanced, which led to a decrease in the strength of the emulsion film so that the water droplets in the emulsions were more likely to coalesce and break. These results are of great significance for the efficient treatment of wastewater from oilfields, promoting the sustainability of environment-friendly oilfield development. Full article

(This article belongs to the Special Issue Research Progress of Surfactants)

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14 pages, 2693 KiB

Open AccessArticle

Study of Interactions between Saponin Biosurfactant and Model Biological Membranes: Phospholipid Monolayers and Liposomes

by Monika Rojewska, Wojciech Smułek, Adam Grzywaczyk, Ewa Kaczorek and Krystyna Prochaska

Molecules 2023, 28(4), 1965; https://doi.org/10.3390/molecules28041965 - 18 Feb 2023

Cited by 6 | Viewed by 2166

Abstract

The aim of this study was to determine the effect of saponins-rich plant extract on two model biological membranes: phospholipid monolayers and liposomes. The Langmuir monolayer technique was used to study the interactions of model phospholipid membranes with saponins. The π–A isotherms were [...] Read more.

The aim of this study was to determine the effect of saponins-rich plant extract on two model biological membranes: phospholipid monolayers and liposomes. The Langmuir monolayer technique was used to study the interactions of model phospholipid membranes with saponins. The π–A isotherms were determined for DPPE (1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine) monolayer with the addition of various concentrations of licorice saponins extracts and subjected to qualitative as well as quantitative analysis. Additionally, relaxation studies of the obtained monolayers were carried out and morphological changes were examined using Brewster angle microscopy. Moreover, changes in the structure of phospholipid vesicles treated with solutions of saponins-rich plant extracts were assessed using the FTIR technique. The size and zeta potential of the liposomes were estimated based on DLS methods. The obtained results indicated that the saponins interact with the phospholipid membrane formed by DPPE molecules and that the stability of the mixed DPPE/saponins monolayer strongly depends on the presence of impurities in saponins. Furthermore, it was found that the plant extract rich in saponins biosurfactant interacts mainly with the hydrophilic part of liposomes. Full article

(This article belongs to the Special Issue Research Progress of Surfactants)

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13 pages, 2267 KiB

Open AccessArticle

Removal of Nutrients from Water Using Biosurfactant Micellar-Enhanced Ultrafiltration

by Sarjana Binte Rafiq Era and Catherine N. Mulligan

Molecules 2023, 28(4), 1559; https://doi.org/10.3390/molecules28041559 - 6 Feb 2023

Cited by 4 | Viewed by 1807

Abstract

The removal of NH₄⁺, NO₃⁻, and NH₃⁻ from wastewater can be difficult and expensive. Through physical, chemical, and biological processes, metals and nutrients can be extracted from wastewater. Very few scientific investigations have employed surfactants [...] Read more.

The removal of NH₄⁺, NO₃⁻, and NH₃⁻ from wastewater can be difficult and expensive. Through physical, chemical, and biological processes, metals and nutrients can be extracted from wastewater. Very few scientific investigations have employed surfactants with high biodegradability, low toxicity, and suitability for ion removal from wastewater at different pH and salinity levels. This research employed a highly biodegradable biosurfactant generated from yeast (sophorolipid) through micellar-enhanced ultrafiltration (MEUF). MEUF improves nutrient removal efficiency and reduces costs by using less pressure than reverse osmosis (RO) and nanofiltration (NF). The biosurfactant can be recovered after the removal of nutrient- and ion-containing micelles from the filtration membrane. During the experiment, numerous variables, including temperature, pH, biosurfactant concentration, pollutant ions, etc., were evaluated. The highest amount of PO₄³⁻ was eliminated at a pH of 6.0, which was reported at 94.9%. Maximum NO₃⁻ removal occurred at 45.0 °C (96.9%), while maximum NH₄⁺ removal occurred at 25.0 mg/L (94.5%). Increasing TMP to 200 kPa produced the maximum membrane flow of 226 L/h/m². The concentrations of the contaminating ion and sophorolipid were insignificant in the permeate, demonstrating the high potential of this approach. Full article

(This article belongs to the Special Issue Research Progress of Surfactants)

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15 pages, 3814 KiB

Open AccessArticle

First Stage of the Development of an Eco-Friendly Detergent Formulation for Efficient Removal of Carbonized Soil

by Andreia P. M. Fernandes, Ana M. Ferreira, Marco Sebastião, Ricardo Santos, Catarina M. S. S. Neves and João A. P. Coutinho

Molecules 2022, 27(21), 7460; https://doi.org/10.3390/molecules27217460 - 2 Nov 2022

Cited by 1 | Viewed by 2945

Abstract

Detergent formulations for cleaning a carbonized soil—degreasers—typically comprise surfactants, organic solvents, phosphate-based cleaning agents, and alkaline agents, which results in high pH values (>11) that raise human and environmental risks. It is important to develop eco-friendly and safer degreasers, while maintaining their cleaning [...] Read more.

Detergent formulations for cleaning a carbonized soil—degreasers—typically comprise surfactants, organic solvents, phosphate-based cleaning agents, and alkaline agents, which results in high pH values (>11) that raise human and environmental risks. It is important to develop eco-friendly and safer degreasers, while maintaining their cleaning efficiency. In this work, simple degreaser formulations, with a pH below 11 and without phosphates, were developed by using a mixture of solvent, surfactant, and water to remove carbonized soil. The efficiency of the new degreaser formulations (with 5 wt% solvent, 5 wt% nonionic or ionic surfactant, and 90 wt% water) was evaluated by an abrasion test in the removal of carbonized soil from ceramic and stainless steel surfaces and compared with a commercial product. The results obtained show that the formulations comprising isopropylene glycol (IPG) with C₁₁–C₁₃ 9EOs and diethylene glycol butyl ether (BDG) with octyltrimethylammonium octanoate ([N₁₁₁₈][C₈O₂]) present the best cleaning efficiency for both surfaces. The composition of these formulations was optimized for each surface using a mixture design. The resulting formulations, despite having a simpler composition, a pH lower than 11, and being phosphate-free, presented a cleaning efficiency equal or slightly higher than the commercial control. These results show that it is possible to design degreasers that are much less aggressive to the environment and user, while simultaneously fulfilling the market requirements. Full article

(This article belongs to the Special Issue Research Progress of Surfactants)

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15 pages, 1527 KiB

Open AccessArticle

Effect of New Surfactants on Biological Properties of Liquid Soaps

by Emilia Klimaszewska, Daria Wieczorek, Sławomir Lewicki, Marta Stelmasiak, Marta Ogorzałek, Łukasz Szymański, Ryszard Tomasiuk and Leszek Markuszewski

Molecules 2022, 27(17), 5425; https://doi.org/10.3390/molecules27175425 - 25 Aug 2022

Cited by 7 | Viewed by 3729

Abstract

Liquid soaps are the basic cosmetics used to clean the skin of the hands. Frequent hand washing prevents viral contamination but may damage the skin’s hydro-lipid layer, leading to various types of irritation. Therefore, four liquid soap formulas were developed with three amphoteric [...] Read more.

Liquid soaps are the basic cosmetics used to clean the skin of the hands. Frequent hand washing prevents viral contamination but may damage the skin’s hydro-lipid layer, leading to various types of irritation. Therefore, four liquid soap formulas were developed with three amphoteric surfactants: Cocamidopropyl Betaine (LS II), CocamidopropylHydroxysultaine (LS III), and newly synthesized Evening PrimroseaamidopropylSulfobetaine (LS IV). We evaluated the skin irritating potential (zein number, bovine albumin test) and cytotoxicity (AlamarBlue™, Cell viability, and Cell cycle assays) on HaCaT cell line. We observed lower values of the zein number and bovine albumin tests after adding soaps with surfactants (the highest differences in LS IV) compared to the base soap (LS I). However, LS I and LS II did not differ in cytotoxic assays. Therefore, adding LS III and LS IV seems potentially more dangerous to the cells. However, it should be noted that cells were continuously exposed to liquid soaps for more than 24 h, so its cytotoxic effects after dermal use in humans may be unnoticeable. Concluding, results suggest that the newly synthesized LS IV should improve the safety of liquid hand washing soaps. Full article

(This article belongs to the Special Issue Research Progress of Surfactants)

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23 pages, 4563 KiB

Open AccessArticle

Wetting Properties of Rhamnolipid and Surfactin Mixtures with Triton X-165

by Edyta Rekiel, Anna Zdziennicka, Katarzyna Szymczyk and Bronisław Jańczuk

Molecules 2022, 27(15), 4706; https://doi.org/10.3390/molecules27154706 - 23 Jul 2022

Cited by 1 | Viewed by 1384

Abstract

The wetting properties of the rhamnolipid and surfactin mixtures with Triton X-165 were considered based on the contact angle measurements of their aqueous solution on the polytetrafluoroethylene (PTFE), polymethyl methacrylate (PMMA) and quartz (Q) surfaces. The obtained contact angle isotherms were described by [...] Read more.

The wetting properties of the rhamnolipid and surfactin mixtures with Triton X-165 were considered based on the contact angle measurements of their aqueous solution on the polytetrafluoroethylene (PTFE), polymethyl methacrylate (PMMA) and quartz (Q) surfaces. The obtained contact angle isotherms were described by the exponential function of the second order as well as by Szyszkowski equation in some cases. Using the contact angle isotherms of individual biosurfactants and TX165 as well as the earlier obtained isotherms of their surface tension the contact angle isotherms of the biosurfactants mixtures with TX165 were deduced. As follows the presence of the maxima on the contact angle isotherms of the biosurfactants mixtures with TX165 is justified. They do not prove negative adsorption of the biosurfactant and TX165 at the interfaces. However, the mutual exchange of the biosurfactant and TX165 molecules is observed in the layers at the interfaces. The concentration of the studied mixtures at the PTFE-solution interface was established to be close to that at the solution-air one but that at the PTFE-air is equal to zero. However, the concentration of the studied mixtures at the PMMA-solution and quartz-solution is greater than zero. The concentration at the PMMA(quartz)-air and PMMA(quartz)-solution interfaces is smaller than that at the solution-air one. Full article

(This article belongs to the Special Issue Research Progress of Surfactants)

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22 pages, 30234 KiB

Open AccessArticle

Thermodynamic Analysis of the Adsorption and Micellization Activity of the Mixtures of Rhamnolipid and Surfactin with Triton X-165

by Edyta Rekiel, Anna Zdziennicka, Katarzyna Szymczyk and Bronisław Jańczuk

Molecules 2022, 27(11), 3600; https://doi.org/10.3390/molecules27113600 - 3 Jun 2022

Cited by 13 | Viewed by 1963

Abstract

The surface tension of aqueous solutions of Triton X-165 with rhamnolipid or surfactin mixtures was measured. The obtained results were applied for the determination of the concentration and composition of the Triton X-165 and biosurfactants mixture at the water–air interface as well as [...] Read more.

The surface tension of aqueous solutions of Triton X-165 with rhamnolipid or surfactin mixtures was measured. The obtained results were applied for the determination of the concentration and composition of the Triton X-165 and biosurfactants mixture at the water–air interface as well as the contribution of the particular component of the mixtures to water surface tension reduction and the mutual influence of these components on the critical micelle concentration. The determination of these quantities was based on both the commonly used concepts and a new one proposed by us, which assumes that the composition of the mixed monolayer at the water–air interface depends directly on the pressure of the monolayer of the single mixture component and allows us to determine the surface concentration of each mixture component independently of surface tension isotherms shape. Taking into account the composition of the mixed monolayer at the water–air interface, the standard Gibbs adsorption free energy was considered. The obtained results allow us to state that the concentration of both mixture components corresponding to their saturated monolayer and the surface tension of their aqueous solution can be predicted using the surfactants’ single monolayer pressure and their mole fraction in the mixed monolayer determined in the proposed way. Full article

(This article belongs to the Special Issue Research Progress of Surfactants)

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20 pages, 2470 KiB

Open AccessReview

Application of Biosurfactants in Medical Sciences

by Xiaoyan Wang, Jiachen An, Tianyu Cao, Mingmin Guo and Fu Han

Molecules 2024, 29(11), 2606; https://doi.org/10.3390/molecules29112606 - 1 Jun 2024

Cited by 1 | Viewed by 1550

Abstract

Biosurfactants derived from microorganisms have attracted widespread attention in scientific research due to their unique surface activity, low toxicity, biodegradability, antibacterial properties, and stability under extreme conditions. Biosurfactants are widely used in many fields, such as medicine, agriculture, and environmental protection. Therefore, this [...] Read more.

Biosurfactants derived from microorganisms have attracted widespread attention in scientific research due to their unique surface activity, low toxicity, biodegradability, antibacterial properties, and stability under extreme conditions. Biosurfactants are widely used in many fields, such as medicine, agriculture, and environmental protection. Therefore, this review aims to comprehensively review and analyze the various applications of biosurfactants in the medical field. The central roles of biosurfactants in crucial medical areas are explored, like drug delivery, induction of tumor cell differentiation or death, treating bacterial and viral effects, healing wounds, and immune regulation. Moreover, a new outlook is introduced on optimizing the capabilities of biosurfactants through modification and gene recombination for better use in medicine. The current research challenges and future research directions are described, aiming to provide valuable insights for continuous study of biosurfactants in medicine. Full article

(This article belongs to the Special Issue Research Progress of Surfactants)

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32 pages, 4589 KiB

Open AccessReview

Multiheaded Cationic Surfactants with Dedicated Functionalities: Design, Synthetic Strategies, Self-Assembly and Performance

by Łukasz Lamch, Weronika Szczęsna, Sebastian J. Balicki, Marcin Bartman, Liliana Szyk-Warszyńska, Piotr Warszyński and Kazimiera A. Wilk

Molecules 2023, 28(15), 5806; https://doi.org/10.3390/molecules28155806 - 1 Aug 2023

Cited by 2 | Viewed by 2250

Abstract

Contemporary research concerning surfactant science and technology comprises a variety of requirements relating to the design of surfactant structures with widely varying architectures to achieve physicochemical properties and dedicated functionality. Such approaches are necessary to make them applicable to modern technologies, such as [...] Read more.

Contemporary research concerning surfactant science and technology comprises a variety of requirements relating to the design of surfactant structures with widely varying architectures to achieve physicochemical properties and dedicated functionality. Such approaches are necessary to make them applicable to modern technologies, such as nanostructure engineering, surface structurization or fine chemicals, e.g., magnetic surfactants, biocidal agents, capping and stabilizing reagents or reactive agents at interfaces. Even slight modifications of a surfactant’s molecular structure with respect to the conventional single-head–single-tail design allow for various custom-designed products. Among them, multicharge structures are the most intriguing. Their preparation requires specific synthetic routes that enable both main amphiphilic compound synthesis using appropriate step-by-step reaction strategies or coupling approaches as well as further derivatization toward specific features such as magnetic properties. Some of the most challenging aspects of multicharge cationic surfactants relate to their use at different interfaces for stable nanostructures formation, applying capping effects or complexation with polyelectrolytes. Multiheaded cationic surfactants exhibit strong antimicrobial and antiviral activity, allowing them to be implemented in various biomedical fields, especially biofilm prevention and eradication. Therefore, recent advances in synthetic strategies for multiheaded cationic surfactants, their self-aggregation and performance are scrutinized in this up-to-date review, emphasizing their applications in different fields such as building blocks in nanostructure engineering and their use as fine chemicals. Full article

(This article belongs to the Special Issue Research Progress of Surfactants)

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14 pages, 1008 KiB

Open AccessReview

Biosurfactants: Forthcomings and Regulatory Affairs in Food-Based Industries

by Deepansh Sharma, Deepti Singh, Gadhwal Monika Sukhbir-Singh, Bhoomika M. Karamchandani, Gajender Kumar Aseri, Ibrahim M. Banat and Surekha K. Satpute

Molecules 2023, 28(6), 2823; https://doi.org/10.3390/molecules28062823 - 21 Mar 2023

Cited by 19 | Viewed by 5036

Abstract

The terms discussed in this review—biosurfactants (BSs) and bioemulsifiers (BEs)—describe surface-active molecules of microbial origin which are popular chemical entities for many industries, including food. BSs are generally low-molecular-weight compounds with the ability to reduce surface tension noticeably, whereas BEs are high-molecular-weight molecules [...] Read more.

The terms discussed in this review—biosurfactants (BSs) and bioemulsifiers (BEs)—describe surface-active molecules of microbial origin which are popular chemical entities for many industries, including food. BSs are generally low-molecular-weight compounds with the ability to reduce surface tension noticeably, whereas BEs are high-molecular-weight molecules with efficient emulsifying abilities. Some other biomolecules, such as lecithin and egg yolk, are useful as natural BEs in food products. The high toxicity and severe ecological impact of many chemical-based surfactants have directed interest towards BSs/BEs. Interest in food surfactant formulations and consumer anticipation of “green label” additives over synthetic or chemical-based surfactants have been steadily increasing. BSs have an undeniable prospective for replacing chemical surfactants with vast significance to food formulations. However, the commercialization of BSs/BEs production has often been limited by several challenges, such as the optimization of fermentation parameters, high downstream costs, and low yields, which had an immense impact on their broader adoptions in different industries, including food. The foremost restriction regarding the access of BSs/BEs is not their lack of cost-effective industrial production methods, but a reluctance regarding their potential safety, as well as the probable microbial hazards that may be associated with them. Most research on BSs/BEs in food production has been restricted to demonstrations and lacks a comprehensive assessment of safety and risk analysis, which has limited their adoption for varied food-related applications. Furthermore, regulatory agencies require extensive exploration and analysis to secure endorsements for the inclusion of BSs/BEs as potential food additives. This review emphasizes the promising properties of BSs/BEs, trailed by an overview of their current use in food formulations, as well as risk and toxicity assessment. Finally, we assess their potential challenges and upcoming future in substituting chemical-based surfactants. Full article

(This article belongs to the Special Issue Research Progress of Surfactants)

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