Surfactant Concentration Research Articles

Secondary Atomization and Micro-Explosion Effect Induced by Surfactant and Nanoparticles on Enhancing the Combustion Performance of Al/JP-10/OA Nanofluid Fuel.

Aluminum/tetrahydrodicyclopentadiene/oleic acid (Al/JP-10/OA) nanofluid fuel is considered a potential fuel for aircraft powered by aviation turbine engines. However, an optimized formula for an Al/JP-10/OA system inducing a secondary atomization and micro-explosion effect and improving the burning performance needs to be developed. With this aim, in this work, the combustion characteristics of pure JP-10, JP-10/OA, JP-10/Al, and Al/JP-10/OA were experimentally tested, and a comparative analysis was conducted. Specifically, the influence of the surfactant and nanoparticle concentrations on the combustion characteristics of Al/JP-10/OA nanofluid fuel, including the flame structure, the flame temperature, the burning rate, the secondary atomization and micro-explosion effect, etc., were evaluated in detail. The results demonstrate that the addition of OA surfactant and Al nanoparticles had a significant effect on the burning rate of fuel droplets. The OA had an inhibition effect, while the Al nanoparticles had a promotion effect. As both OA and Al nanoparticles were added to the JP-10, the synergetic effect had to be considered. At the optimum ratio of OA to Al for the best suspension stability, there is a critical Al concentration of 1.0 wt.% from promotion to inhibition with increases in the Al concentration. The addition of OA and Al nanoparticles induced the secondary atomization and micro-explosion, resulting in an unsteady combustion and chaotic flame structure. The transient flame temperature of hundreds of Kelvins increased, the high-temperature flame zone widened, and thus, the energy release was elevated. Therefore, the combustion performance and energy release of Al/JP-10/OA nanofluid fuel can be improved through the secondary atomization and micro-explosion effect induced by the surfactant and nanoparticles.

Development of a friction factor correlation applicable to both wet and dry foam flow in circular vertical pipes

BackgroundFoam flow, distinguished by its low density and extensive specific surface area, is employed for the cleaning of plant systems. However, its dual nature as a gas-liquid mixture and a non-Newtonian fluid complicates the prediction of the frictional pressure drop. MethodsThis study constructed a laboratory-scale experimental setup to illustrate the upward flow behavior of aqueous foam in a vertical circular pipe, capturing the foam flow using a high-speed camera. Utilizing the collected data and images, a model was developed for the friction factor to predict the frictional pressure drop of the foam flow, under the assumption that the foam flow is a non-Newtonian, quasi-homogeneous, steady, and fully developed laminar flow. Significant findingsWet foam, characterized by small, uniformly distributed spherical bubbles, is observed at lower foam quality levels. In contrast, dry foam, marked by a larger mean bubble diameter, non-uniform bubble distributions, and slugs, is observed at higher foam quality levels. A notable inflection point in the frictional pressure drop is observed during the transition from wet to dry foam within a vertical pipe. The foam regime and frictional pressure drop characteristics of the foam flow show limited sensitivity to surfactant concentration within the experimental range. A correlation for friction factors, applicable to both wet and dry foam flows in vertical circular pipes, was developed based on the Reynolds number, exhibiting a prediction error of 23.6 %.

Digestion of surfactants does not affect their ability to inhibit P-gp-mediated transport in vitro

While various non-ionic surfactants at low concentrations have been shown to increase the transport of P-gp substrates in vitro, in vivo studies in rats have shown that a higher surfactant concentration is needed to increase the oral absorption of e.g. the P-gp substrates digoxin and etoposide. The aim of the present study was to investigate if intestinal digestion of surfactants could be the reason for this deviation between in vitro and in vivo data. Therefore, Kolliphor EL, Brij-L23, Labrasol and polysorbate 20 were investigated for their ability to inhibit P-gp and increase digoxin absorption in vitro. Transport studies were performed in Caco-2 cells, while P-gp inhibition and cell viability assays were performed in MDCKII-MDR1 cells. Polysorbate 20, Kolliphor EL and Brij-L23 increased absorptive transport and decreased secretory digoxin transport in Caco-2 cells, whereas only polysorbate 20 and Brij-L23 showed P-gp inhibiting properties in the MDCKII-MDR1 cells. Polysorbate 20 and Brij-L23 were chosen for in vitro digestion prior to transport- or P-gp inhibiting assays. Brij-L23 was not digestible, whereas polysorbate 20 reached a degree of digestion around 40%. Neither of the two surfactants showed any significant difference in their ability to affect absorptive or secretory transport of digoxin after pre-digestion. Furthermore, the P-gp inhibiting effects of polysorbate 20 were not decreased significantly. In conclusion, the mechanism behind the non-ionic surfactant mediated in vitro P-gp inhibition seemed independent of the intestinal digestion and the results presented here did not suggest it to be the cause of the observed discrepancy between in vitro and in vivo.

Investigation on foam properties of Gemini quaternary ammonium salt containing hydroxyl hydrophilic headgroup

Four Gemini quaternary ammonium salts, tetramethylene-1,4- bis [N, N-bis(hydroxypropyl)-hexa/decyloxypropylammonium] bromide (GC6/10-P) and tetramethylene-1,4-bis [N, N-bis(hydroxyethyl)-hexa/decyloxypropylammonium] bromide (GC6/10-E) were synthesized by two-step reactions. This study analyzes the foam properties, including foamability, foam stability, and foam size distribution, of GC6/10-P and GC6/10-E using the Foamscan method. The influence of surfactant concentration and gas flow rate on the properties of Gemini quaternary ammonium salt foam was also studied. Additionally, the relationship between surfactant structure and foam morphology in aqueous solutions was discussed. The results show that all four types of Gemini quaternary ammonium salt surfactants are low-foaming surfactants. The foam capacity (FC) sequence is as follows: GC10-E > GC10-P > GC6-E > GC6-P. The foamability and foam stability are enhanced with increasing surfactant concentration, which increases the adsorbed quantity of surfactant molecules at the air-water interface. The foam produced by GC6-P/E systems is the most unstable; the foam behaviors show faster Ostwald ripening and drainage process in aqueous system. It seems that 150–200 mL/min is an ideal air intake speed. The presence of hydroxyl in the molecular structure enhances the formation of hydrogen bonding between surfactants and water molecules, leading to greater molecular compactness. The results indicate that the foaming behavior of hydroxyl Gemini quaternary ammonium salts can be correlated with concentration and alkyl chains. Foamscan are proposed to research the foaming and foam stability behavior and provide a useful guide for evaluating the foamability of cationic surfactants-based systems, especially in the development of environmentally friendly foam systems suitable for low-foaming products.

Effects of short-chain alcohols and urea on the association of tetradecyltrimethylammonium bromide surfactant and cefixime trihydrate antibiotic: Conductometric and physicochemical analysis

This study explores the interaction of tetradecyltrimethylammonium bromide (TTAB), with an antibiotic drug, cefixime trihydrate (CMT), with a particular focus on conductivity changes as a reliable indicator of micelle formation. Influence of various alcohols (methanol (MeOH), ethanol (EtOH), 1-propanol (1-PrOH), 2-propanol (2-PrOH)), and urea on the physicochemical properties for micellization of TTAB in aq. alcohols/urea solutions of CMT was investigated. As the concentration of alcohol and urea increases, the critical micelle concentration (CMC) undergoes a notable rise, while the degree of counterion binding (β) shows a decreasing trend as a function of [alcohols]/[urea]. Elevated temperatures impede the creation of micelles, directing to an increase in the CMC, thus necessitating a higher surfactant concentration for micelle development. The alterations in free energy (∆Gmo), enthalpy (∆Hmo), entropy (∆Smo), and molar heat capacity (∆Cm0) were analyzed to evaluate the feasibility and driving forces behind the process of micelle development. The negative values of ∆Gmo indicate that the formation of micelles in the system being studied occurs spontaneously. The ∆Hmo and ∆Smo values suggest the existence of electrostatic forces (ion-dipole and H-bonding) between the components (TTAB, CMT, and alcohol) in aq. MeOH media. In contrast, hydrogen bonding, electrostatic forces, and hydrophobic interactions are involved in the solutions of the other three alcohols and urea medium. The thermodynamic parameters of transfer (∆Gm,tr0, ∆Hm,tr0, and ∆Sm,tr0) and enthalpy-entropy compensation variables were computed and discussed for TTAB micelles in the presence of CMT drug in employed solvents. The discoveries hold significant implications for drug formulation and industrial processes concerning surfactants and additives, providing valuable insights for optimizing their performance and properties.

Characterizing the Microparticles Deposition Structure and its Photonic Nature in Surfactant-Laden Evaporating Colloidal Sessile Droplets.

This work presents a simple method to create photonic microstructures via the natural evaporation of surfactant-laden colloidal sessile droplets on a flat substrate. In the absence of dissolved surfactant, the evaporating colloidal droplet forms a well-known coffee ring deposition. In contrast, the presence of surfactant leads to the formation of multiple ring structures due to the repetitive pinning-depinning behavior of the droplet contact line (CL). It is found that the multiring structure shows vibrant iridescent structural colors while the coffee ring lacks a photonic nature. This difference in the structural color for the presence and absence of the surfactant is found to be dependent on the arrangement of the particles in the deposition structure. The particle arrangement in the multirings is monolayered and well-ordered. The ordering of the particles is strongly influenced by the particle dynamics, contact angle (CA), and CL dynamics of the evaporating colloidal solution droplet. Furthermore, the iridescent nature of the multiring deposition is demonstrated and explained. The dependence of the multiring deposition structure on the concentration of the dissolved surfactant and the suspended particles is also studied. The findings demonstrate that an intermediate surfactant concentration is desirable for the formation of a multiring structure. Further, the pinning-depinning CL dynamics that causes the formation of the multiring deposition structure is discussed. Finally, we demonstrate the applicability of the approach to smaller droplet volumes.

Effect of cationic Gemini surfactants ethonium and decamethoxin on the spectral properties, solubility and tautomerism of the curcumin

AbstractThe properties of natural polyphenol curcumin in water solutions of cationic Gemini surfactants decamethoxin and ethonium, which have similar positively charged nitrogen hydrophilic head groups but different spacer sizes and lengths of hydrophobic tails have been investigated in a wide range of concentrations by using UV–Vis spectroscopy and quantum‐chemical calculations. It was found that curcumin dissolves in the organized micellar media of these surfactants in the enol tautomeric form and its solubility increases 400 times compared to water. The binding constants of curcumin with decamethoxin and ethonium were determined by the solubility method. Significant differences in the influence of premicellar concentrations of cationic Gemini surfactants on the solubility and tautomeric transformations of curcumin were revealed. In contrast to decamethoxin, ethonium at a concentration below the CMC promotes a significant increase in the solubility of curcumin and a shift in the tautomeric equilibrium towards the formation of its keto form.

Surfactant-Enhanced Assisted Spontaneous Imbibition for Enhancing Oil Recovery in Tight Oil Reservoirs: Experimental Investigation of Surfactant Types, Concentrations, and Temperature Impact

Surfactant-assisted spontaneous imbibition is an important mechanism in enhanced oil recovery by capillary pressure in low permeability and tight oil reservoirs. Though many experiments have been conducted to study the mechanism of enhanced oil recovery by surfactant-assisted spontaneous imbibition, the effects of surfactant type, concentration, and temperature have not been well studied. Using tight sandstone outcrop core samples with similar permeability and porosity, this paper experimentally studies surfactant-assisted spontaneous imbibition using three different surfactant types, i.e., sodium dodecylbenzene sulfonate (SDBS), cocamidopropyl betaine (CAB), and C12–14 fatty alcohol glycoside (APG). In addition to the type of surfactant, the effect of the surfactant concentration and the temperature is also investigated. The study results show that the ultimate oil recovery of spontaneous imbibition with formation water and denoised water is about 10%. Surfactant can significantly improve the oil recovery of spontaneous imbibition by reducing the interfacial tension between oil and water, emulsifying crude oil and improving oil mobility. APG showed better performance compared to SDBS and CAB, with a maximum oil recovery factor of 36.19% achieved with formation water containing 0.05% APG surfactant. Lower concentrations (0.05% APG) in the formation water resulted in a higher oil recovery factor compared to 0.1% APG. Increasing temperature also improves oil recovery by reducing oil viscosity. This empirical study contributes to a better understanding of the mechanism of surfactant-assisted spontaneous imbibition and enhanced oil recovery in tight oil reservoirs.

Designing the structure of cationic star-shaped trimeric surfactants most active in micelle formation using molecular connectivity indices

A model expressing the relationship between the logarithm of critical micelle concentration of cationic star-shaped trimeric surfactants and topological indices was obtained using only molecular connectivity indices. Based on the obtained model, the exemplary compound most active in micelle formation was designed. The analysis of the influence of various structural factors on the value of the critical micelle concentration was supported by atomic charge studies. The obtained model will be used to design new star-shaped trimeric surfactants that are more active in formation of micelle as well as to predict their critical micelle concentration.

Potentiometric Surfactant Sensor with a Pt-Doped Acid-Activated Multi-Walled Carbon Nanotube-Based Ionophore Nanocomposite.

Two new surfactant sensors were developed by synthesizing Pt-doped acid-activated multi-walled carbon nanotubes (Pt@MWCNTs). Two different ionophores using Pt@MWCNTs, a new plasticizer, and (a) cationic surfactant 1,3-dihexadecyl-1H-benzo[d]imidazol-3-ium-DHBI (Pt@MWCNT-DHBI ionophore) and (b) anionic surfactant dodecylbenzenesulfonate-DBS (Pt@MWCNT-DBS ionophore) composites were successfully synthesized and characterized. Both surfactant sensors showed a response to anionic surfactants (dodecylsulfate (SDS) and DBS) and cationic surfactants (cetylpyridinium chloride (CPC) and hexadecyltrimethylammonium bromide (CTAB)). The Pt@MWCNT-DBS sensor showed lower sensitivity than expected with the sub-Nernstian response of ≈23 mV/decade of activity for CPC and CTAB and ≈33 mV/decade of activity for SDS and DBS. The Pt@MWCNT-DHBI surfactant sensor had superior response properties, including a Nernstian response to SDS (59.1 mV/decade) and a near-Nernstian response to DBS (57.5 mV/decade), with linear response regions for both anionic surfactants down to ≈2 × 10-6 M. The Pt@MWCNT-DHBI was also useful in critical micellar concentration (CMC) detection. Common anions showed very low interferences with the sensor. The sensor was successfully employed for the potentiometric titration of a technical grade cationic surfactant with good recoveries. The content of cationic surfactants was measured in six samples of complex commercial detergents. The Pt@MWCNT-DHBI surfactant sensor showed good agreement with the ISE surfactant sensor and classical two-phase titration and could be used as an analytical tool in quality control.

Study of the flow pattern and pressure drop law of the air-water-foam three-phase flow

The inaccurate prediction of flow patterns and pressures after adding different types and concentrations of surfactants to wellbores and drainage lines is a common problem in shale gas wells and tubing foam drainage. To clarify the change rule of the air–water-foam three-phase flow pattern and pressure drop after adding different types and concentrations of surfactants, a surface tension test was conducted in this study. In addition, visual air–water-foam three-phase flow indoor simulation experiments were performed with various surfactants such as cocamidopropyl hydroxysulfobetaine (MX-1), dodecyldimethyl betaine (TCJ-1), and sodium α-alkenyl sulfonate (XJHSM), surfactant concentrations (0.3–0.6 %), oil pipe diameters, pipe inclinations, gas–liquid ratios, and oil contents on large-scale experimental equipment. Based on the gas–liquid distribution characteristics, the air–water-foam three-phase flow patterns in the inclined tube were reclassified, and the quantitative conversion boundaries of the various flow patterns were determined. Based on the pressure drop pulse characteristics, characterization parameters such as the scaling factor, foaming capacity, foam density, and gas-holding rate were introduced after considering the effects of various factors on the pressure drop weights, enabling a new pressure drop calculation method for air–water-foam three-phase flows for application to different types and concentrations of surfactants. The errors were verified using data from previous studies and field measurements that were within 15% and 5%, respectively. The results of these studies provide a better understanding of the air–water-foam three-phase flow patterns and pressure drop variations in shale gas wells and gathering lines.

Enhanced surfactant remediation of diesel-contaminated soil using O3 nanobubbles

Currently, nanobubbles are widely discussed in environmental research due to their unique properties, including significant specific surface area, transfer efficiency, and free radical generation. In this study, O2 and O3 nanobubbles (diameters ranging from 0 to 500 nm) were combined with conventional surfactant technology to investigate their enhanced efficacy in removing diesel contaminants from soil. The impact of various factors such as surfactant concentration, temperature, and soil aging duration on pollutant removal rates was examined across different experimental approaches (stirring/flushing). Soil samples subjected to different treatments were characterized using TG-DTG and FTIR analysis, while GC/MS was employed to assess the degradation products of diesel constituents in the soil. The results indicated that the elution efficiencies of the three surfactants (SDS, SDBS, and TX-100) for diesel in soil correlated positively with concentration (0.3–1.4 CMC) and temperature (18–60 °C), and inversely with aging time (10–300 days), with the elution capacity was SDS > SDBS > TX-100. Mechanical stirring (500 rpm) and temperature variations (18–60 °C) did not affect the stability of the nanobubbles. Upon the introduction of O3 nanobubbles to the surfactant solution, there was a consistent increase in both the removal (degraded and removed) efficiency and rate of diesel under varying experimental conditions, resulting in an enhancement of removal rates by approximately 8–15%. FTIR spectroscopy showed that surfactants containing O3 nanobubbles mitigated the impact on the primary functional groups of soil organic matter. GC/MS analyses indicated that residual pollutants were predominantly alkanes, with degradation difficulty ranking as: alkanes < alkenes < cycloalkanes < aromatic compounds. TG-DTG coupled with GC/MS analysis demonstrated that O3 nanobubbles contributed to a reduction in surfactant residues. This study significantly advances our understanding of how nanobubbles facilitate and optimize surfactant-assisted remediation of contaminated soil, thereby advancing the precise application of nanobubble technology in soil remediation.

Optimizing the preparation parameters of eco‐friendly flexible polyurethane foams derived from a corn‐based bio‐polyol

AbstractCorn‐based bio‐polyol is employed as an alternative for petroleum‐based polyol to prepare an eco‐friendly polyurethane (PU) foam via a one‐shot method. By varying ratio of gelling catalyst, blowing catalyst, and surfactant during the preparation process, the compression performance, cell morphology, and thermal stability of the PU foam are analyzed. The results obtained indicate that an increase in surfactant content yielded improved foam stability, whereas increased amounts of blowing and gelling catalysts resulted in enhanced compression performance. An optimized foaming process is determined with an NCO/OH ratio of 1.2, 0.2 parts per hundred polyols (pphp) of gelling catalyst, 0.1 pphp of blowing catalyst, and 0.1 pphp of surfactant. Under these specific conditions, the PU foam exhibits a uniform cell structure, exceptional compression performance, and good thermal stability, comparable to those of a reference foam derived from petroleum‐based polyol.

Surfactant Composition Dependent Evolution of Electronic/Structural Properties of P3HT Nanoparticle Colloids Synthesized via Mini-Emulsion Technique

: This study investigates the influence of surfactant (sodium dodecyl sulfate, SDS) concentration on the size and optoelectronic properties of poly(3-hexylthiophene) (P3HT) nanoparticles (NPs) synthesized via the mini-emulsion technique. P3HT NPs were fabricated with varying SDS concentrations. The size dependent optoelectronic properties, including the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) levels, were analyzed through photoelectron spectroscopy in air, UV-Vis absorption spectroscopy and cyclic voltammetry. A clear trend of decreasing NP size with increasing SDS concentration was observed. Higher SDS levels resulted in smaller NPs with enhanced pi-pi stacking and shorter conjugation lengths. This structural change led to a noticeable shift in HOMO and LUMO levels, indicating a direct correlation between surfactant concentration and the electronic properties of the P3HT NPs. The absorption spectra revealed a decrease in the A0-0/A0-1 ratio with smaller NP size, suggesting a transition towards more pronounced H-aggregate characteristics. As the size of the P3HT NPs decreases, there is a notable increase in H-aggregate formation. This increase can be attributed to enhanced interchain interactions between the polymer chains. In smaller NPs, the surface area-to-volume ratio is higher, leading to more significant interactions between adjacent polymer chains. These interactions promote the formation of H-aggregates, characterized by their interchain pi-pi stacking, which differs from the intrachain coupling observed in J-aggregates.

Water-in-Oil Emulsion Temporal and Spatial Evolution at Static Conditions and Its Impact on Pipeline Restart

Summary Understanding emulsion evolution at static conditions is crucial for production operations, such as pipeline operations during the shut-in and restart process and separator optimal design. This study experimentally investigated the temporal and spatial evolution of water-in-oil emulsion properties under static conditions. Numerical simulations were conducted to study their impacts on pipeline restart operations. The experiments were conducted in graduated glass cylinders, with mineral oil and tap water as the testing fluids and Span® 80 as the surfactant. Different water cuts, mixing speeds, and surfactant concentrations were investigated. Along with idle time at static conditions, the mixture demonstrated two layers, namely an upper oil layer and a lower emulsion layer, except for the lowest surfactant concentration that gave a third additional free-water layer at the bottom. Experimental results showed a dramatic increase in viscosity in the emulsion layer with time and depth, which was closely related to the increase in the water volumetric fraction. The increase rate slowed down and plateaued out with time. The increase rate is also related to water cut, mixing speed, and surfactant concentration. Experimental results also show that the relationships between the viscosity and water cut for separated emulsion follow the master curve of viscosity and water cut for homogeneous emulsion. This suggests that one can estimate the viscosity using the master curve given the water volumetric fraction. The numerical simulation was conducted for pipelines with a valley configuration and with the fluid properties obtained from the experimental measurements. It demonstrates that a higher pressure is required to restart the flow to the original flow rate. It also shows that the flow rate may not be able to resume its original value given the same pressure boundaries due to the accumulation of dense emulsion layers in the horizontal and upward inclined sections. For example, for a 16-m pipe, the flow cannot be restarted given the same inlet pressure (100 Pa). It can only resume 4.6% of the original flow rate when the pressure is elevated to 300 Pa.

Development of a Quantitative Analysis Method for Fragrances in a Sample Containing High Concentrations of Surfactants (Part I) – Fabric Softeners –

Development of a Quantitative Analysis Method for Fragrances in a Sample Containing High Concentrations of Surfactants (Part I) – Fabric Softeners –

Prediction of globule size and globule size distribution of emulsion liquid membrane in a pulsed packed column

In this work, the emulsion globule size of an ELM system in a pulsed packed column in different surfactant concentrations was studied for the first time. The emulsion liquid membrane consists of kerosene as a diluent and Span 80 as a surfactant. The effect of surfactant concentration and hydrodynamic parameters, including pulse intensity and flow rates of the dispersed phase and continuous phase, on globule size, was investigated. Based on the results, increasing the concentration of Span 80 up to 3.5 % v/v results in 58–64 % reduction in the Sauter mean diameter (D32) and narrowing the size distribution of the globules. Operating parameters such as pulse intensity and flow rates of continuous and dispersed phases have been investigated so that the influence of flow rates was considerably smaller than the effect of pulse intensity on the globule size distribution. Also, the results showed that with increasing pulse intensity, D32 decreased by 29 %. A new empirical correlation for D32 calculation was also suggested, Featuring 4.91 % average absolute relative error (AARE). Finally, the globule size distribution was predicted using the normal probability function and the dimensionless correlations accurately predicted their parameters and the measured %AARE of α and β were 8.3 and 3.4, respectively.

Comparison of dodecyl trimethyl ammonium bromide (DTAB) and cetylpyridinium chloride (CPC) as corrosion inhibitors for mild steel in sulphuric acid solution

Two essential cationic surfactants, dodecyl trimethyl ammonium bromide (DTAB) and cetyl pyridinium chloride (CPC) with differences in the alkyl chain, were investigated as corrosion inhibitors on mild steel (MS) in 0.5 M H2SO4 with weight loss (WL) and the potentiodynamic polarization (PDP) method. Three different temperatures were used to maintain the reported sample solutions (298.15, 308.15, and 318.15 K) for concentrations ranging below, above, and at the optimum critical micelle concentration (CMC) of the cationic surfactants. Results show that 0.5 M DTAB having ammonium group gave higher inhibition efficiency than 0.5 M CPC having pyridinium group by PDP method. The inhibition efficiencies were determined as 98.6% for 0.5 M DTAB and 89.38% for 0.5 M CPC after 24 h immersion at 298.15 K. The extreme inhibition efficiency depends on the chain length and decreases with an increase in temperature as well as increases with the addition of concentration of cationic surfactants. Around CMC, both surfactants CPC and DTAB showed the highest inhibition efficiency which follows the isotherm of Langmuir adsorption and illustrates a mixed type of corrosion inhibitors with the predominance of cathodic reactions. Additionally, the proposed mechanisms of inhibitors showing both physical and chemical adsorption confirmed by the free energy of adsorption (-ΔGads0) for DTAB were >28–34.5 kJ/mol and for CPC were >31.07–42.91 kJ/mol.

Tannic acid coated nanosuspension for oral delivery of chrysin intended for anti-schizophrenic effect in mice

Chrysin is a flavonoid drug with numerous therapeutic activities. It suffers from low intestinal absorption owing to its hydrophobicity. Therefore, the aim of this study is to exploit the efficient technique of nanosuspension (NSP) to formulate chrysin-NSP coated with tannic acid (TA) to improve the solubility and anti-schizophrenic activity of chrysin. A 23 full factorial design was constructed where the independent factors were type of polymer, surfactant concentration (0.5 or 1 %) and the aqueous phase volume (5 or 15 mL), while the dependent responses were the particle size (PS) of the obtained formulation as well as the % chrysin dissolved after 2 h (Q2h). The optimum formulation (NSP-4) composed of 1 % PEG 400 and 1 % Cremophor RH40 in 15 mL aqueous phase. It achieved a PS and Q2h values of 108.00 nm and 38.77 %, respectively. NSP-4 was then coated with TA (TA-coated NSP-4) for further enhancement of chrysin solubility. TA-coated NSP-4 revealed PS and zeta potential values of 150 ± 14 nm and –32.54 ± 2.45 mV, respectively. After 6 h, chrysin dissolved % were 53.97 and 80.22 for uncoated NSP-4 and TA-coated NSP-4, respectively, compared with only 9.47 for free chrysin. The developed formulations and free chrysin were assessed regarding their effect on schizophrenia induced in mice by cuprizone (CPZ). Treatment with the developed formulations and free chrysin ameliorated demyelination and behavioral deficit induced by CPZ via elevating MBP and PI3K/PKC activities as well as reducing GFAP expression levels. The developed formulations and free chrysin inhibited Galactin-3 and TGF-β expressions and stimulated GST antioxidant enzyme. Furthermore, they maintained the balances in glutamatergic and dopaminergic neurotransmission via modulation on neuregulin-1 and alleviated nuclear pyknosis and degeneration in the neurons. The order of activity was: TA-coated NSP-4 > NSP-4 > free chrysin.

The Role of Nanoparticles in Sunscreen: UV Protection and Particle Size

Sunscreen formulas are essential for protecting the skin from damaging UV rays, which reduces the risk of sunburn, skin cancer, and premature aging. However, conventional sunscreens frequently lack further advantages including anti-aging and antioxidant capabilities. Strong polyphenolic component epigallocatechin-3-gallate (EGCG), present in green tea extracts, has anti-inflammatory, antioxidant, and photoprotective properties. Similar to this, poly amino acids and hyaluronic acid (HA) have hydrating, anti-aging, and skin-repairing qualities. In this work, we investigated the co-delivery of EGCG and HA/poly amino acids in sunscreen formulations using nano-carriers, namely transferosomes and polymeric nanoparticles. To increase the effectiveness of these nano-carriers, a number of formulation factors, such as the drug-polymer ratio, surfactant concentration, homogenization speed, and sonication time, were improved. When compared to normal EGCG solutions, the optimized nano-formulations showed superior properties such reduced particle size, higher encapsulation efficiency, and improved skin permeability. Studies on cytotoxicity showed that the nano-formulations were not harmful to skin cells and that they increased cell viability when compared to EGCG in its purest form. Because the nano-formulations contained EGCG and HA/poly amino acids, they offered considerable protection against skin damage caused by UV radiation. The spherical shape of the nano-carriers was shown by transmission electron microscopy, and the lack of interactions between EGCG and excipients was validated by differential scanning calorimetry and Fourier-transform infrared spectroscopy.