Effect Of Surfactants Research Articles

Effect of surface charge on laser-produced silver nanoparticles for dye reduction and surface-enhanced Raman spectroscopy

Silver nanoparticles (Ag NPs) are widely used in biological, chemical, and physical fields due to their distinct properties. However, the effect of surfactants with different polarities on the catalytic and surface-enhanced Raman spectroscopy (SERS) performance of Ag NPs has not been thoroughly studied. Here, we tailor the surface charge of laser-synthesized Ag NP without changing their morphology and investigate their catalytic and SERS capabilities. The surfactant-free silver nanoparticles (NPBare), synthesized via pulsed laser ablation in liquid (PLAL), are subsequently coated with ionic surfactants sodium dodecyl sulfate (NPSDS) and cetyltrimethylammonium bromide (NPCTAB). The synthesis and morphology of Ag NPs are confirmed using UV-Vis absorption spectroscopy and scanning electron microscopy. The surface charge of fabricated NPs is determined using zeta potential (ZP) measurements. The ZP values of NPBare, NPSDS, and NPCTAB are determined to be -17 mV, 28.7 mV, and 5.58 mV, respectively. The catalytic activity of bare and coated Ag NPs was tested against the cationic and anionic dyes, Methylene blue (MB) and Methyl orange (MO) respectively. The reduction rate of both dyes was highest when using NPBare. However, in the case of coated nanoparticles, the rate of MB and MO reduction depends on the difference between the ZP of the dye and nanoparticles: the rate of reduction increases with the difference between the zeta potentials of the dye and coated nanoparticles increases. The SERS capability of bare and coated NPs was evaluated for anionic (MO) and cationic (MB, Rhodamine B, and Crystal Violet) dyes. The SERS intensity of dyes strongly enhanced with the increase in ZP difference between the dye molecules and NPs. Surface charge modified NPs shown excellent SERS sensitivity with detection limit up to nanomolar for dye molecules as well as the homogeneity of NPs demonstrated in Raman mapping results with relative standard deviation of 17%. The results suggest that the electrostatic interaction between the nanoparticles and dye molecules plays a dominant role in SERS enhancement. These findings highlight the significance of surface charge in improving the catalytic and sensing properties of noble metal nanoparticles.

Investigating intermolecular interactions of surfactant solutions using femtosecond thermal lens spectroscopy

In this study, we examined the impact of various surfactants (oleic acid, butyric acid, Span-20, and CTAB) on the thermophysical properties of methanol (MeOH) using a femtosecond laser-induced thermal lens (TL) spectroscopic technique. Methanol was chosen for its unique convective properties under intense localized heating, making it a promising candidate for studying photothermal responses. We discovered that the TL characteristics of both pure methanol and methanol-surfactant mixtures are significantly influenced by the molecular interactions and physical properties of the components. Our experimental results indicate that the addition of surfactants notably alters the heat transfer dynamics of the solvent by restricting natural molecular movement and modifying thermal properties, which in turn affect the TL signatures. Beyond the surfactant concentration, we observed that the extent of variation in steady-state TL signals, inflection points, and heat transfer mechanisms depends on the molecular properties of the surfactants, such as chain length, the number of active (hydrophilic) groups per molecule, thermal conductivity, viscosity, and intermolecular interactions. Our TL findings provide a detailed investigation into the effect of surfactants on the photothermal response and heat transfer process of a solvent for the first time.

Resonance and surfactant effects on the interaction of a rising bubble and a sedimenting particle in an oscillating fluid

This paper considers the interaction of a rising bubble and a sedimenting fine particle in a liquid with a soluble surfactant subjected to the gravity field, forced flow, and vibrations. The frequency of vibrations is close to the resonance value. The particle motion trajectories are calculated, taking into account its inertia, fluid viscosity, Basset force, buoyancy force, and the mean force acting on the particle due to the inhomogeneity of the pulsating field. The collision efficiency is evaluated, and the cross sections of the sedimenting particles captured by the rising bubble are found. It is demonstrated that even at low vibration intensity but in the presence of a weak surfactant effect, a significant increase in the probability of particle–bubble collision and in the capture cross section can be achieved. The obtained results can be used to intensify the flotation processes by ultrasonic treatment.

Endotracheal Surfactant and Budesonide Combination Therapy in Neonatal Acute Respiratory Distress Syndrome due to Late-Onset Sepsis.

Neonatal acute respiratory distress syndrome (NARDS) is an important cause of hypoxemic respiratory failure. This study aimed to investigate the short-term effects of endotracheal surfactant and budesonide combination therapy on NARDS secondary to late-onset neonatal sepsis (LONS). This was a retrospective, cross-sectional, and observational study. Newborns with NARDS due to LONS who received endotracheal surfactant and budesonide combination therapy between August 2022 and September 2023 were included in this study. Oxygenation status before endotracheal surfactant and budesonide treatment were compared with the values obtained two hours after treatment. Among 20 neonates, 10 (50%) were diagnosed with severe NARDS, and 10 (50%) were diagnosed with moderate NARDS. The mean corrected gestational age was 33.3±2.9 w when endotracheal surfactant and budesonide were administered to the neonates. The need for the fraction of inspired oxygen (0.75 [0.57-1.00]% vs. 0.55 [0.44-0.80]%; mean difference [MD]: 17.50%, 95% confidence interval [CI]: 14.99 to 22.50) and oxygen saturation index (OSI; 8.03 [4.98-13.94] vs. 4.71 [4.11-8.93]; MD: 2.23, 95% CI: 1.22 to 3.24) decreased (P=0.001 and P<0.001, respectively) after endotracheal surfactant and budesonide treatment. However, preductal oxygen saturation (SpO2 ; 93 [91-94]% vs. 95 [94-96]%; MD: -3.50%, 95% CI: -5.00 to -2.00) increased significantly after endotracheal surfactant and budesonide treatment when compared to pre-treatment values (P<0.001). The reduction in oxygen demand and OSI, along with an increase in SpO2 after treatment compared to pre-treatment values, suggests that endotracheal surfactant and budesonide combination therapy could be an effective option to improve oxygenation in NARDS secondary to LONS.

Surfactants govern the fabrication of sulfur-enriched heterojunction catalysts for highly selective photocatalytic conversion of toluene

Photocatalytic selective oxidation of toluene represents a milder and more environmentally friendly strategy for the synthesis of benzaldehyde. In order to enhance catalytic performance, efficient carrier separation and transport are crucial in the photocatalytic process. This study focused on the preparation of ZnS@ZnIn2S4 with sulfur vacancies and heterostructures, combining the advantages properties of ZnS and ZnIn2S4 in photocatalysis. The effects of ZnS and surfactants on the catalytic properties of the composites were studied in depth. Characterization tests revealed that surfactant-modified ZnS@ZnIn2S4 exhibited a higher concentration of sulfur defects, which facilitated electron trapping and promoted photogenerated carrier separation and utilization. Additionally, the present study also demonstrated that the incorporation of ZnS and surfactants could reduce the crystal size of ZnIn2S4, thereby facilitating the exposure of additional active sites. The synergistic effect of the aforementioned advantages enabled toluene to undergo oxidation at a conversion rate of 39% in the presence of oxygen, resulting in the production of benzaldehyde with an exceptional selectivity of 92%. This finding offers valuable insights for future endeavors in designing photocatalytic C-H bond oxidation catalysts.

Effect of Tween 80 and Pluronic 127 on the stabilization of zein nanocarriers for the delivery of piperine

In the current research work, zein-based polymeric nanocarriers were developed for the delivery of piperine, where the effect of non-ionic surfactants (Tween 80 and Pluronic F-127) on the stability and in vitro drug release characteristics were studied. Physiochemical characterization studies showed that the particle size of blank and drug-loaded surfactant stabilized zein nanoparticles were <200 nm and particles were spherical in shape. FTIR studies confirmed the successful incorporation of piperine within the zein nanoparticle without any alteration in primary structure of zein. The circular dichroism spectroscopy suggested that α-helix content of zein was reduced following the incorporation of drug within nanoparticles. The solubility of piperine was enhanced significantly in the gastrointestinal tract, and higher sustained release was observed for tween 80-stablized zein nanoparticles. The formulations were stable towards thermal treatment up to 90 °C, showed superior resistance towards aggregation even at ionic strength >50 mM NaCl, and did not show any aggregation even at the isoelectric pH. Tween 80-stablized zein nanoparticles showed good redispersibility index with the cryoprotectant mannose (5 % w/v) after lyophilization. The current research would contribute to the advancement of zein nanoparticles for the delivery of nutraceutical agents, which may be utilized in the food supplements or therapeutic agents to improve the human health.

Investigation of thermal properties of TiN/MWCNT-OH hybrid nanofluids and GWO-BP neural network model

Hybrid nanofluids have garnered significant attention due to excellent heat transfer performance and potential applications. Conducting comprehensive research on hybrid nanofluids holds paramount importance. This study investigates the effects of surfactants, particle concentrations, mixing ratio and storage time of TiN/MWCNT-OH hybrid nanofluids on stability, thermal conductivity, and viscosity. It proposes a Grey Wolf Optimizer-Backpropagation neural network model for predicting thermal properties. The results indicate that the inclusion of PVP-K30 surfactant leads to remarkable stability of hybrid nanofluids at a concentration of 50 ppm over a period of two weeks. An increase in the proportion of MWCNT-OH results in a slight increase in thermal conductivity, which exhibits a maximum increase of 46 % with elevated temperature and particle concentrations. The viscosity of hybrid nanofluids gradually decreases as temperature rises, although demonstrates a non-linear correlation with concentrations. The neural network model exhibits a high predictive accuracy of 99.3507 % for thermal conductivity and 98.8924 % for viscosity.

The investigation of Gemini surfactant effects on CH4 and CO2 hydrates

The investigation of Gemini surfactant effects on CH4 and CO2 hydrates

Effect of novel non-inhibitor slurry on chemical mechanical polishing properties of copper interconnect copper film based on experiments and theoretical calculations

In order to simplify the component of copper slurry during chemical mechanical polishing (CMP) and improve the surface corrosion inhibition efficiency, anionic surfactant dodecylbenzene sulfonic acid (DBSA) and nonionic surfactant decyl glucoside (DG) as mixed surfactants were used instead of inhibitors, and the corrosion inhibition properties were thoroughly studied by experiments and theoretical calculations. Polishing experiments and surface morphology tests show that the mixed surfactants can effectively enhance the surface quality after CMP compared with traditional inhibitor TAZ. Electrochemical experiments show that DG and DBSA can form a dense passivation film on the Cu surface to prevent corrosion. The inhibition efficiency of mixed surfactants is as high as 95 %. The theoretical calculations indicate that DBSA and DG form a stable long-chain structure, which leads to a higher adsorption energy, a denser passivation film, and stronger corrosion inhibition, in agreement with the experimental findings. These studies confirmed the stronger inhibitory effect of mixed surfactant on Cu film CMP and provided a new reference for the design of simplified slurry without inhibitor components.

Влияние катионоактивного, анионоактивного и неионогенного поверхностно-активных веществ на почвенные олигохеты Eisenia fetida andrey (Bouche, 1972)

Results of studying the main types of surfactants effect on earthworms Eisenia fetida andrey (Bouche, 1972) are presented. The worms were tested for survival and preference-avoidance behavioral reactions. Earthworms avoided sodium dodecyl sulfate (SDS) at 0.02 g/kg and above, cetyltrimethylammonium bromide – at 0.1 g/kg and above, and polysorbate 80 – at 30 mL/kg and above. The 100% mortality of earthworms occurred at 0.001, 0.01 and 0.02 g/kg of SDS on day 30, at 1 g/kg – on day 25, and at 1 g/kg – on day 2 of the experiment. Сetyltrimethylammonium bromide at 0.001 and 0.01 g/kg caused the 100% mortality of worms on day 30; at 0.1 g/kg – on day 25; at 0.5 g/kg – on day 5; and at 1.0 g/kg already on day 2 of the experiment. The 100% mortality of worms occurred at 0.1, 1 and 10 mL/kg of polysorbate 80 on day 30 of incubation; at 20 or 30 mL/kg – on day 20; at 50 mL/kg – on day 10 of experience. The following toxicity series (both in terms of g/L and in terms of g/mol) of the tested surfactants for earthworms was constructed on the basis of the results obtained (increasing toxicity): polysorbate 80 (non-ionic surfactant) &lt; cetrimonium bromide (cationic surfactant) &lt; sodium dodecyl sulfate (anion-active surfactant).

Effect of Non-ionic Surfactant on Fe-N-C Catalyst Layers under HT-PEMFC Conditions

The effect of different non-ionic surfactant contents on Fe-N-C gas diffusion electrode (GDE) coating and performance is investigated. GDEs are tested under high temperature polymer electrolyte membrane fuel cell (HT-PEMFC) conditions at 160 °C and concentrated phosphoric acid electrolyteFe-N-C-based GDEs are fabricated through ultrasonic spray coating with Tergitol contents of 0, 1, 20 and 50 wt% in the catalyst layer (CL). Thereby, the PTFE to catalyst ratio is kept constant at 1.0 in the CL. The H2O contact angle decreases with increasing Tergitol™ content in the CL, revealing an increased wettability. H3PO4 contact angles of Tergitol containing GDEs show a same wettability at room temperature as at 160 °C. GDE half-cell setup investigations show, that Tergitol leads to flooding of the electrode by the electrolyte and coverage of the active sites by the surfactant and thus a performance decay.

Effect of Non-ionic Surfactant on Fe-N-C Catalyst Layers under HT-PEMFC Conditions

The effect of different non-ionic surfactant contents on Fe-N-C gas diffusion electrode (GDE) coating and performance is investigated. GDEs are tested under high temperature polymer electrolyte membrane fuel cell (HT-PEMFC) conditions at 160 °C and concentrated phosphoric acid electrolyteFe-N-C-based GDEs are fabricated through ultrasonic spray coating with Tergitol contents of 0, 1, 20 and 50 wt% in the catalyst layer (CL). Thereby, the PTFE to catalyst ratio is kept constant at 1.0 in the CL. The H2O contact angle decreases with increasing Tergitol™ content in the CL, revealing an increased wettability. H3PO4 contact angles of Tergitol containing GDEs show a same wettability at room temperature as at 160 °C. GDE half-cell setup investigations show, that Tergitol leads to flooding of the electrode by the electrolyte and coverage of the active sites by the surfactant and thus a performance decay.

The Effect of Different Surfactants and Polyelectrolytes on Nano-Vesiculation of Artificial and Cellular Membranes.

Nano- and micro-sized vesicular and colloidal structures mediate cell-cell communication. They are important players in the physiology of plants, animals, and humans, and are a subject of increasing interest. We investigated the effect of three surfactants, N-cetylpyridinium chloride (CPC), sodium dodecyl sulfate (SDS), and Triton X-100 (TX100), and two anionic polyelectrolytes, sodium polystyrene sulfonate (NaPSS) and sodium polymethacrylate (NaPMA), on nanoliposomes. In addition, the effect of SDS and TX100 on selected biological membranes (erythrocytes and microalgae) was investigated. The liposomes were produced by extrusion and evaluated by microcalorimetry and light scattering, based on the total intensity of the scattered light (Itot), hydrodynamic radius (Rh), radius of gyration (Rg), shape parameter p (=Rh/Rg,0), and polydispersity index. The EPs shed from erythrocytes and microalgae Dunaliella tertiolecta and Phaeodactylum tricornutum were visualized by scanning electron microscopy (SEM) and analyzed by flow cytometry (FCM). The Rh and Itot values in POPC liposome suspensions with added CPC, SDS, and TX100 were roughly constant up to the respective critical micelle concentrations (CMCs) of the surfactants. At higher compound concentrations, Itot dropped towards zero, whereas Rh increased to values higher than in pure POPC suspensions (Rh ≈ 60-70 nm), indicating the disintegration of liposomes and formation of larger particles, i.e., various POPC-S aggregates. Nanoliposomes were stable upon the addition of NaPSS and NaPMA, as indicated by the constant Rh and Itot values. The interaction of CPC, SDS, or TX100 with liposomes was exothermic, while there were no measurable heat effects with NaPSS or NaPMA. The SDS and TX100 increased the number density of EPs several-fold in erythrocyte suspensions and up to 30-fold in the conditioned media of Dunaliella tertiolecta at the expense of the number density of cells, which decreased to less than 5% in erythrocytes and several-fold in Dunaliella tertiolecta. The SDS and TX100 did not affect the number density of the microalgae Phaeodactylum tricornutum, while the number density of EPs was lower in the conditioned media than in the control, but increased several-fold in a concentration-dependent manner. Our results indicate that amphiphilic molecules need to be organized in nanosized particles to match the local curvature of the membrane for facilitated uptake. To pursue this hypothesis, other surfactants and biological membranes should be studied in the future for more general conclusions.

Surfactant-Assisted Regulation of WS2/Tourmaline Microstructures for Excellent Photocatalytic Performance

The controllable electrical and optical properties of two-dimensional tungsten disulfide (WS2) attracted much attention in photocatalysis, but commercial development has been severely restricted by their restacking properties. Surfactant-assisted synthesis techniques can be considered as an effective option to break this bottleneck. In this work, the effect of surfactants including sodium dodecylbenzene sulfonate (SDBS), hexadecyltrimethylammonium bromide (CTAB), and polyvinylpyrrolidone (PVP) on the microstructure of WS2/tourmaline composites prepared by coupled hydrothermal and calcination methods was explored. The WS2 nanosheets were uniformly deposited on the tourmaline surface with the assistance of 1.0 mmol/L SDBS. Meanwhile, WS2/Tour-SDBS exhibited the highest rhodamine B (RhB) degradation activity, which was 1.8 and 2.3 times higher than that of photocatalysts prepared with CTAB and PVP under the same conditions, respectively. This study provides a new tactic for the fabrication of high-performance WS2-based composites.

Nanoconfinement effect on the miscible behaviors of CO2/shale oil/surfactant systems in nanopores: Implications for CO2 sequestration and enhanced oil recovery

Currently, CO2 flooding is the most promising carbon capture, utilization, and storage (CCUS) technology in the energy industry. Understanding the nanoconfinement effect on the CO2-oil miscible process is crucial for accurately determining the minimum miscibility pressure (MMP) of CO2/oil in shale reservoirs. In this study, we conducted molecular dynamics (MD) simulations to investigate the effects of pore size, surfactants, and pore type on the MMP of nanoconfined CO2/shale oil/surfactant systems. Validations against experimental data show a deviation of 2.98 % in the CO2 MMP. The MMPs under nanoconfinement are found to be significantly lower than those in bulk phase conditions (up to 22.94 %). The simulation results reveal that decreasing pore size can enhance the miscibility of CO2 and oil by increasing the CO2 adsorption ratio, improving CO2-surfactant interactions, and inhibiting the tendency of CO2 molecules to self-aggregate. The enhancement of CO2-oil miscibility caused by surfactants is ranked by CFP > SF > SDS according to the mixing degrees (Dmix) and the spatial distribution of CO2 around surfactant molecules. In addition, pore type exhibits various abilities in influencing the MMP, owing to their different mineral surface properties and ability to influence CO2-surfactant interactions. Nanopores with stronger hydrophobicity and a denser CO2 distribution around surfactant molecules have lower MMPs. The results show that the order of MMP in terms of pore types is Quartz < Kaolinite < I/M clay. This study elaborates the micro-mechanisms of surfactant-assisted CO2-oil miscibility under nanoconfinement, offering valuable insights for effectively designing CO2 miscible flooding in shale oil reservoir development.

Mechanisms of surfactant improving water injection huff and puff efficiency in tight reservoir

Water injection huff and puff is an economical and effective method to enhance the recovery of tight oil reservoir, in which the addition of suitable surfactants is critical, but its mechanism needs to be further studied. In this paper, the huff and puff process is divided into replenishment, imbibition and water flooding stages. This study compared and analyzed the effects of various surfactants on interfacial tension, wettability, flow resistance, and oil washing efficiency, using mineralized water as the control group. The relationships between different surfactants and imbibition recovery efficiency, water flooding recovery efficiency, and flooding pressure were investigated. The mechanisms by which surfactants influence the imbibition and flooding processes were also explored. The results show that, the effect of permeability on imbibition and water flooding recovery efficiency in natural cores can be ignored. During the imbibition stage, the maximum recovery efficiency with mineralized water is 18.33 %, while with surfactants it is 21.40 %. In the water flooding stage, the maximum recovery efficiency with mineralized water is 3.89 %. The addition of surfactants significantly increases the water flooding recovery efficiency to 19.82 %. Furthermore, surfactants can reduce the water flooding pressure by approximately 7.00 MPa and increase the total recovery rate by about 5.00 %. The primary mechanisms by which surfactants improve the water injection huff and puff effect include reducing interfacial tension, altering wettability, facilitating crude oil detachment from rock surfaces, and enhancing oil washing efficiency. Reduction of flow resistance, leading to a decrease in the pressure required for flooding. The research results provide a theoretical basis for the practical application of surfactants in water injection huff and puff in tight reservoirs.

Antilisterial effect of alkyl polyglycosides biosurfactant and modes of action

Several outbreaks of Listeria monocytogenes originated mainly from contaminated contact surfaces. Thus, this study investigated the antilisterial effect of natural surfactants in terms of their use as a 2-in-1 sanitizing washer on a food contact surface and evaluated their modes of action. The antilisterial activity of alkyl polyglycosides (APGs), namely capryl glucoside (CA), coco glucoside (CG), and decyl glucoside (DG), was evaluated based on the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) using broth dilution assay. The results showed that CG had the strongest antilisterial activity. Therefore, CG was selected for further investigation. The time-kill assay showed a lethal effect of 0.5 % (w/w) CG by inactivating 4 Log reduction (99.99 %) of L. monocytogenes within 3 s. Furthermore, 1 % (w/w) CG with slight mechanical force in washing (by shaking) was efficient for sanitizing a stainless-steel coupon surface based on its ability to cause a total reduction of deposited L. monocytogenes (99.9 %) within 10 min. Scanning electron microscopy and applying Fourier-transform infrared spectroscopy revealed that CG chemically disrupted the cell wall and plasma membrane of L. monocytogenes within 5 min after a gentle wash. The results showed it had potent antimicrobial activity and was bactericidal against L. monocytogenes. Overall, our results supported the use of CG as a natural antibacterial surfactant to alter the chemical sanitizer and the possibility of its practical use in the food industry and for household use.

Effect of surfactants on the degree of polydispersity of suspensions of polystyrene latex spheres

Effect of surfactants on the degree of polydispersity of suspensions of polystyrene latex spheres

Effect of micelles-forming surfactant on performance of anaerobic digestion of synthetic municipal wastewater

Effect of micelles-forming surfactant on performance of anaerobic digestion of synthetic municipal wastewater

Colloid thermophoresis in surfactant solutions: Probing colloid-solvent interactions through microscale experiments.

Thermophoresis has emerged as a powerful tool for characterizing and manipulating colloids at the nano- and micro-scales due to its sensitivity to colloid-solvent interactions. The use of surfactants enables the tailoring of surface chemistry on colloidal particles and the tuning of interfacial interactions. However, the microscopic mechanisms underlying thermophoresis in surfactant solutions remain poorly understood due to the complexity of multiscale interaction coupling. To achieve a more fundamental understanding of the roles of surfactants, we investigated the thermophoretic behavior of silica beads in both ionic and nonionic surfactant solutions at various background temperatures. We provide a complete mechanistic picture of the effects of surfactants on interfacial interactions through mode-coupling analysis of both electrophoretic and thermophoretic experiments. Our results demonstrate that silica thermophoresis is predominantly governed by the dissociation of silanol functional groups at silica-water interfaces in nonionic surfactant solutions, while in ionic surfactant solutions, the primary mechanism driving silica thermophoresis is the adsorption of ionic surfactants onto the silica surface.