HLB Value Research Articles

Rapid HCFC-141b hydrate formation and high-density cold storage in the presence of acid ester surfactants

To improve HCFC-141b hydrate production, eco-friendly nonionic surfactants were used as promoters to enhance hydrate formation. Stearic acid polyoxyethylene ester (SG) effectively improve HCFC-141b hydrate formation, and the promotion effect is influenced by the hydrophilicity and mass fraction of surfactant. Ethylene oxide (EO) numbers of SG series surfactants affect on hydrate nucleation induction time and cold storage density. Surfactants with appropriate HLB values have better promotion effects. Hydrate has shorter induction times and higher cold storage density with SG-20. When the concentration of SG-20 is 1 %, the induction time reduces to 36 min, and the cold storage density is up to 245.1 kJ/kg, which is the optimal addition amount for HCFC-141b hydrate production. Comparing the three systems, the HCFC-141b hydrate system with 1 wt% SG-20 has the best cycling stability.

Study of the rheology and flow risk of hydrate slurries containing combined anti-agglomerants: Effects of wax, water cut and continuous phase composition

As oil and gas extraction increasingly ventures into deep-sea environments, the issues surrounding the flow safety of hydrate and wax deposits have become more critical. There is an urgent need to develop environmentally friendly and adaptable hydrate anti-agglomerants, and to expand the database and knowledge base for risk management strategies to ensure optimal production safety. This study formulated combined anti-agglomerants with varying HLB values using Span 80 and Tween 80 in different ratios. Rheological experiments were conducted to investigate their synergistic anti-agglomeration performance in water-in-oil emulsions and their adaptability in environments with wax, varying water contents, and different continuous phase compositions. The results indicate that, in comparison to a single anti-agglomerant, the combined anti-agglomerants not only increases the critical time for hydrate formation but also reduces peak viscosity and stable viscosity by 23–90 % and 25–85 %, respectively. Additionally, an index for assessing the flow risk of hydrate slurries under specific conditions was proposed, which demonstrates that the combined anti-agglomerant with an HLB value of 8.6 exhibits exceptional performance across various conditions. This finding is significant for refining risk management strategies for hydrates in deep-sea oil and gas transportation processes.

Oil-in-water microemulsion of Arthrospira platensis carotenoid as antiphotooxidation in vitamin C beverages

Arthrospira platensis is a blue-green microalgae that has carotenoid as the main pigments, with the largest content being beta-carotene. Carotenoids are a type of pigment that is water insoluble, unstable, and has a limited bioavailability. One of the efforts to improve its solubility and stability, especially with regard to its anti-photooxidation capabilities, is to make it into a microemulsion. This study aimed to develop the most stable oil-in-water (O/W) microemulsion containing carotenoids from A. platensis for use as an antiphotooxidation agent in vitamin C beverages. Microemulsions consist of three distinct phases: oil, water and surfactant. The oil phase consisted of virgin coconut oil (VCO) or palm oil, with 7.5% and 15% and the aqueous phase was distilled water at a concentration of 65% or 80%. The surfactant used a combination of Tween 80, Tween 20, and Span 80 with a final hydrophilic-lipophilic balance or HLB value of 14.5. All microemulsion formulations were incubated for 24 hrs before being tested for stability by centrifugation at 3000 rpm for 30 mins, heating at 105oC for 5 hrs, and storage for 2 and 4 weeks. The resulting turbidity index was used to test the microemulsion's stability. The most stable microemulsion was chosen as a delivery system for carotenoid compounds. The carotenoid microemulsion was also tested by centrifugation, heating, and stability at different pH (6.5 and 4.2) and in varied ratios (1:1, 1:9 and 1:99). The results revealed that the concentration of oil and water phases in the microemulsion formulation influenced the microemulsion's stability. The best formulation obtained was a microemulsion with 7.5% of virgin coconut oil, 80% of water concentration, and surfactant with a ratio of 92:5.5:2.5 (Tween 80: Span 80:Tween 20). The most stable carotenoid microemulsion was a microemulsion with 100 ppm of carotenoid added. The carotenoid microemulsion was able to inhibit photooxidation at 4000 lux for 4 hrs. The vitamin C beverage model added with 6 ppm carotenoid microemulsion was able to inhibit photooxidation compared to the control and 12 ppm, for up to 6 hrs and there was a significant decrease in vitamin C and antioxidants after 24 hrs of photooxidation. A. platensis carotenoid microemulsion with a concentration of 6 ppm could inhibit photooxidation on vitamin C beverages for up to 6 hrs.

Effect of Melamine Formaldehyde Resin Encapsulated UV Acrylic Resin Primer Microcapsules on the Properties of UV Primer Coating.

Ultra-Violet (UV) coatings are widely adaptable of substrates and produce low emissions of volatile organic compounds. UV coatings can extend service life by adding self-healing microcapsules that restore integrity after sustaining damage. In this study, UV coating was used as a core material; microcapsules were produced and added to the UV coating to enhance its self-healing property, providing a good protection for both the UV coating and the substrate. UV primer microcapsules were prepared with UV primer as the core material and melamine formaldehyde resin as the wall material. The UV primer containing more than 98.0% solids content was mainly composed of epoxy acrylic resin, polyester acrylic resin, trihydroxy methacrylate, trimethyl methacrylate, and photo initiator. The preparation process of the UV primer microcapsules was optimized. Further, the UV coating was prepared with better UV primer microcapsules, and the effects of the UV primer microcapsules alongside the comprehensive properties of the coating were studied. The best preparation process for the UV primer microcapsules was as follows: the wall-core mass ratio was 1:0.50, Triton X-100 and Span-20 as emulsifiers with an HLB value of 10.04, the microcapsule reaction temperature was 70 °C, and the reaction time of the was 3.0 h. When the quantity of the UV primer microcapsules increased in the coating, color difference ΔE of the coating increased, gloss decreased, transmittance decreased, elongation at break increased and then decreased, roughness increased, and self-healing rate first increased and then decreased. When the addition of the UV primer microcapsules reached 2.0%, the color difference ΔE of the coating was 1.71, the gloss was 106.63 GU, the transmittance was 78.80%, the elongation at break was 3.62%, the roughness was 0.204 μm, and the self-healing rate was 28.56%, which were the best comprehensive properties of the UV primer. To improve the comprehensive properties of the UV coatings, the UV coatings were modified by a microcapsule technology, which gave the UV coatings a better self-healing property. The application range of microcapsules for the UV coatings was broadened. Based on the previous research of microcapsules in UV coatings, the results further refined the study of the effects of adding self-healing microcapsules to UV coatings using the UV coating itself as the core material.

Effect of UV Top Coating Microcapsules on the Coating Properties of Fiberboard Surfaces.

The commonly used ultraviolet ray (UV) curing coatings have the characteristics of fast curing speed, high hardness, strong abrasion resistance, etc. However, the self-healing properties of UV coatings after being damaged still need to be improved. Self-healing microcapsules can alleviate this problem. The UV top coating itself has good properties, so it can be directly chosen as the core material of microcapsules. UV top coating microcapsules can be added to the UV top coating to increase the self-healing properties of the UV coating to achieve the purpose of better protection of the UV coating and fiberboards. UV top coating microcapsules were prepared and added in different contents to characterize the effect on the physical, chemical, and self-healing properties of the UV coating on a fiberboard surface. The 1#, 2#, and 3# UV top coating microcapsules that were prepared with emulsifier HLB values of 10.04, 10.88, and 11.72, respectively, were added to the UV top coating at contents of 2.0%, 4.0%, 6.0%, 8.0%, and 10.0%. The UV coatings were applied to the fiberboard using a method of two primers and two top coatings, in which no microcapsule was added in the primer, and were tested and analyzed. The results showed that when the content of microcapsules was greater than 6.0%, close to 8.0%, the excessive density of microcapsules produced stacking and extrusion between the microcapsules. As a result, the core material could not flow out smoothly when part of the microcapsule was ruptured. The outflow of the core material was not efficiently utilized, thus leading to a decrease in the self-healing rate. The 2# UV top coating microcapsules of 4.0% made the UV coatings reach the self-healing rate of 26.41%. The self-healing rate of the UV coatings prepared with the 3# UV top coating microcapsules with 6.0% was up to 26.58%. The UV coatings prepared with the 1# UV top coating microcapsules of 6.0% had the highest self-healing rate among the three groups, up to 27.32%. The UV coatings of this group had the best comprehensive properties with a chromatic aberration ΔE of 4.08, a gloss of 1.10 GU, a reflectance of 17.13%, an adhesion grade of 3, a hardness of 3H, a grade 3 of impact resistance, and a roughness of 1.677 μm. An investigation of the UV coatings on fiberboard surfaces with the content of UV top coating microcapsules can provide support for the optimization of the self-healing properties of UV coatings and can also provide innovative ideas for the preparation of the self-healing coatings on fiberboard surfaces.

Antimicrobial Activity of Formulated Origanum and Thyme Essential Oil Nanoemulsions - A Comparative Study

Introduction: This study focused on the formulation processing and antimicrobial activities of Origanum and Thyme essential oils (OEO) (TEO) and their nanoemulsions (OEON) (TEON) on gram-positive and gram-negative bacteria and yeast. Optimal nanoemulsion formulation and stability were achieved through balancing between requisite hydrophilic-lipophilic balance (rHLB) and surfactant concentration (Smix) of nanoemulsions. Methods: The smallest droplet sizes of OEON: (z -185.1 nm ± 0.85) and TEON (z -130.1 nm ± 0.60), were achieved by using 10 g/100 mL of OEO and TEO with 15 g/100 mL Smix at ultrasonication for 2 min with no phase separation. The size of nanoemulsion droplet and PDI was found to be influenced by HLB value, treatment time, and Smix concentration. Antimicrobial analyses, including a zone of inhibition, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and time-kill kinetics assay, were performed against Escherichia coli, Staphylococcus aureus, and Saccharomyces cerevisiae. Results: The antimicrobial findings demonstrated that OEO exhibited higher antimicrobial activity compared to TEO (P<0.05). Meanwhile, the OEON and TEON substantially reduced the MIC and MBC values, compared to OEO and TEO against all tested microorganisms (P<0.05). Throughout the time-kill assay, E. coli was reduced by 5 log CFU/ml within 120 minutes, while S. cerevisiae and S. aureus were eradicated after 60 and 120 minutes of incubation with OEON, respectively. Conclusion: In turn, TEON reduced E. coli by 5 log CFU/ml and S. cerevisiae by 4 log CFU/ml within 120 minutes, while S. aureus was inhibited within the same time of incubation with TEON. The nanoemulsion formulations of OEO and TEO considerably enhanced the antimicrobial properties, which provides a promising alternative plant-derived antimicrobial for pharmaceuticals and food applications.

Unlocking the Potential of Hazelnut oil: Formulation and Characterization of a Novel Microemulsion for Enhanced Applications

This study embarked on a quest to develop and characterize a microemulsion, harnessing the potent properties of (Corylus avellana) hazelnut oil. The microemulsions were meticulously prepared through the drop-wise titration, where water was introduced into a harmonious blend of surfactants (castor oil ethoxylate 20, 30, 40 moles) and oil. All transparent ternary mixtures born from this union were subjected to scrutiny, their viscosity, type of emulsion, conductivity, and droplet size carefully characterized. To assess their resilience, the microemulsions were subjected to a stressful trial under the centrifugal force of 3000 RPM for 30 minutes. Based on the symphony of results, a phase diagram was meticulously constructed, orchestrating the corresponding volumes of these three components. Oil, surfactant, and water mixtures, ranging from different ratios that yielded stable emulsions at HLB 9.7, 11.7, and 13.1, produced transparent liquid masterpieces. The constructed phase diagram unveiled regions of diverse microemulsion and emulsion types, each with its unique narrative. Intriguingly, the droplet size of freshly prepared mixtures danced within a wider range (67 to 367 nm) before centrifugation stability testing. The major region of the microemulsion was found at HLB 11.7 with the lowest particle size of 67 nm. It was concluded that hazelnut oil could be formulated into a microemulsion at a specific HLB value of the surfactant, unlocking a myriad of possibilities.

Preparation of UV Topcoat Microcapsules and Their Effect on the Properties of UV Topcoat Paint Film.

An orthogonal experiment was designed to prepare different UV topcoat microcapsules by adjusting the mass ratio of wall material to core material, HLB value of emulsifier, reaction temperature, and reaction time of UV topcoat microcapsule. By testing the morphology and multiple properties of UV topcoat microcapsules, it was found that the biggest factor affecting the synthesis of UV topcoat microcapsules is the emulsifier HLB value. In order to further optimize the performance of UV topcoat microcapsules, a single-factor experiment was conducted with the emulsifier HLB value as the variable, and it was found that the UV topcoat microcapsules achieved the best performance when the emulsifier HLB value was 10.04. The optimal UV topcoat microcapsules were added to the UV topcoat at different amounts to prepare UV topcoat paint films. Through testing the various properties of the UV topcoat paint film, it was determined that the performance of the UV topcoat paint film was optimal when the amount of UV topcoat microcapsules added to the UV topcoat was 4.0%. The optical properties of the UV topcoat paint film were tested, and the effect of UV topcoat microcapsules on the color difference and glossiness of the UV topcoat paint film was not significant. The tensile and self-healing performance of UV topcoat microcapsules were tested. UV topcoat microcapsules can enhance the toughness of the UV topcoat paint film to a certain extent, suppress the generation of microcracks, and have a good self-healing effect. The results provide experimental support for the preparation of microcapsules using UV coatings as core materials for the self-healing of UV coatings.

Microemulsions and Nanoemulsions for Topical Delivery of Tripeptide-3: From Design of Experiment to Anti-Sebum Efficacy on Facial Skin.

The targeted delivery of a hydrophilic Tripeptide-3 to the skin using microemulsions or nanoemulsions for facial oil reduction was the focus of this study. The impact factors affecting oil/water transparent dispersion formation, such as the surfactant system, HLB value, and co-solvent, were identified through the water titration method and pseudoternary phase diagram plots. The interfacial tension between caprylic/capric triglyceride (CCT oil) and water was significantly reduced by the surfactant/co-surfactant combination (Smix) of Cremophore® RH40 and a double-tails co-surfactant, polyglycerol-3-diisostearate, at an HLB of 13 together with a water-to-co-solvent (PG) ratio of 1:1. A two-level full factorial design of experiment (FFD-DoE) emphasized the independent variables of the HLB value, co-solvent, and CCT oil contents affecting the optimal compositions for micro- or nanoemulsion formation. The low-energy spontaneous emulsification of the optimized combination at a low Smix content (10%) yielded the translucent oil-in-water Tripeptide-3 nanoemulsions with an internal droplet size of 25.7 ± 1.20 nm, a narrow polydispersity index of 0.237 ± 0.129, and 70.6 ± 0.58% transmittance. The in vitro skin permeation study revealed a significantly higher skin penetration and retention of the Tripeptide-3 nanoemulsions compared to the high surfactant microemulsions and coarse emulsions. Skin irritation and oil control efficacy were evaluated in healthy volunteers before and after product application for 28 days. The obtained nanoemulsions not only decreased sebum production but also enhanced skin moisture levels. In conclusion, the meticulously designed nanoemulsions, incorporating suitable excipients, show a promising delivery system for hydrophilic peptides to control sebum overproduction in oily facial skin.

Concentrated O/W Emulsion Stability of Non-Ionic Chitosan Oligomer Surfactants Modified by Epoxidized Fatty Chains at pH7: Influence of Emulsification Conditions

In this study, chitosan-based surfactants were synthesized by epoxy–amine chemistry to stabilize concentrated O/W emulsions at pH7. Chitosan was first depolymerized by nitrous deamination to obtain chitooligosaccharides (COS) with degrees of polymerization of 10 (DP10) and 20 (DP20). Then, three different epoxidized fatty chains, i.e., octyl/decyl glycidyl ether (C9), hexadecyl glycidyl ether (C16) and epoxidized cardanol (card), were grafted onto the amine groups of chitosan to form six amphiphilic structures. NMR measurements revealed grafting efficiencies ranging from 1 to 30% while HLB values ranged from 13 to 20. The relationships between these surfactant structures and their adsorption properties were investigated by tensiometric measurements, highlighting the need for a short hydrophilic moiety and high grafting efficiency to obtain the best adsorption. Subsequently, concentrated O/W emulsions (66% of oil) at pH7 were produced using COS-based surfactants and the impact of stirring time and speed during the emulsification process was described through rheological, droplet size and microscopy measurements. Finally, emulsions were stored over 2 months in order to study the destabilization phenomenon into the mixture, i.e., coalescence and creaming, by using laser granulometry and Turbiscan. Results demonstrated that stability could be enhanced by increasing emulsion viscosity, reducing droplet size or optimizing the adsorption layer at the O/W interfaces.

An improved method for determining the water number for surfactants

Surfactants have a significant role in everyday life and various industries. Their amphipathic nature significantly influences their properties, functions, and applicability. The ratio of water and oil solubility is characterized by the HLB value (hydrophilic-lipophilic balance) or the closely related water number.A determination of the water number of surfactants represents the amount of water that a surfactant can incorporate into a microemulsion. The results of measuring the water number provide information about the hydrophilic properties of the surfactant in question. Understanding the water number helps determine the applicability of surfactants. From the water number of surfactants, conclusions can be drawn about the HLB value of the particular surfactant, providing further insights into its properties. Although a well-established method for determining water number has long been available, it has been revealed that many of the auxiliary substances and chemicals used in this process have severe health-damaging effects, leading to their discontinuation in routine laboratory use.Our goal was to find a solvent combination that would be suitable for the water number determination method. Additionally, we aimed to investigate solvents that are environmentally and human-biologically less harmful, easily and affordably obtainable.•The study presents a method for determining the water number of surfactants.•The method is straightforward to execute and free from harmful solvents.•By improving the method, we enhanced the reliability of the examination.

Simultaneous extraction of cadmium, nickel, and cobalt ions from acidic aqueous solutions by emulsion liquid membrane using sunflower-kerosene mixture as a diluent; breakage and mass transfer studies

In this study, a simultaneous removal of cadmium, cobalt, and nickel from an aqueous solution through the Green Emulsion Liquid Membrane (GELM) method was carried out. A 7:3 ratio of sunflower oil to kerosene was utilized as the membrane phase stabilized by Span 80 as the emulsifier. D2EHPA as a carrier and HCl as an inner phase were used. Extraction and stripping efficiencies of 97.45% and 98.42% for Cd2+, 96.82% and 97.84% for Co2+, 89.74% and 92.69% for Ni2+, respectively, with the lowest breakage (0.8%) were obtained under the best operating conditions. An extensive investigation of the influence of homogenizer speed, external and internal phase acidity, the HLB value of the surfactant (Tween 80 and Span 80), surfactant and carrier concentrations, volume ratio of the membrane to internal phase, mixer speed, ratio of external to membrane phase emulsification time and extraction time on the stability of membrane, extraction, and stripping efficiencies were carried out. Kinetic analysis of cadmium, cobalt, and nickel extraction was performed using zero, first, and second-order models at optimum conditions. The experimental data fit well with first-order for three metal ions. The coefficient of the total mass transfer (Ft) of cadmium through the GELM technique was 3.28% higher than that of cobalt and 28.61% higher than that of nickel, while the Ft of cobalt is 25.33% higher than that of nickel. Using the recovered membrane, the extraction of the three metal ions for the initial six cycles was extremely efficient under the best conditions.

Properties Related to the HLB Value of Hybrid Thermoelectric Nanofluids at Different Temperatures.

This article aims to explore the impact of HLB (Hydrophile-Lipophile Balance) values on two key properties, namely the thermoelectric conductivities and the stability of the suspension, of a hybrid nanofluid composed of TiO2 and CuO nanoparticles. The present study employed a two-step synthesis method to prepare the polymeric nanofluid, which meant that the nanoparticles were mixed with the base fluid using an ultrasonic oscillator, which was easier and cheaper than the one-step synthesis method. To ensure that the nanoparticles remain evenly dispersed in the base fluid, two distinct polymer-emulsifier combinations with different HLB values were employed as the dispersing agents. The first pair of polymeric emulsifiers consisted of Span#20 and Tween#20, and the second pair was Span#80 and Tween#80 composed to four HLB values of 12, 13, 14, and 15. The experiment measured the properties of the nanofluid, including the particle size, Zeta potential, and thermoelectric conductivities at different temperatures from 20 °C to 50 °C. The experimental outcomes indicated that an HLB value of 13 was the best for the two sets of polymeric emulsifiers tested. This value corresponded to the most reduced particle size, measured at 170 nm, alongside the most elevated Zeta potential, recorded at -30 mV. Additionally, this HLB value was associated with the peak thermoelectric conductivity, which was 1.46 W/m∙K. This suggests that there may be some variation in the best HLB value depending on the type of polymeric emulsifiers and the temperature of the hybrid nanofluid.

Investigation of Oil in Water Emulsion properties depending on the change of Emulsifiers combinations

Oil in water emulsion formulations as dosage forms for topical application are intended to produce the therapeutic effect in the skin. Their quality features mainly depend on the choice of emulsifying combination composition. This work aimed at establishing a mixture of oil phase, water and combinations of different kinds of emulsifiers to screen factors that affect the quality features of oil in water emulsion cream`s formulations. Eleven formulations were prepared with different ratio of different kinds of emulsifiers by a high temperature method. The emulsions were prepared with oil phase having calculated HLB value range 10.96 and emulsifiers having HLB values ranged from 0.20 to 14.60. The formulated oil in water emulsion compositions were evaluated for physical stability, rheological properties, colloidal and thermodynamic stability, microscopy observation. The results showed that not all formulations were physically stable after 24h storage period. Stable formulations were subjected to rheological properties studies. Some of samples presented the flow which was close to the Newtonian fluid, others showed pseudo-plastic flow type. The results of colloidal and thermodynamic stability evaluations allowed to establish the regularities between the type of the flow and formulations` stability. When varying the ratio of emulsifiers, the total HLB range of the mixture changed, which also affected the dispersion properties of emulsion systems. With certain ratios of emulsifiers the dispersion of the system increased.

The Effect of High-Pressure Homogenization Conditions on the Physicochemical Properties and Stability of Designed Fluconazole-Loaded Ocular Nanoemulsions.

The growing interest in high-energy emulsification is a result of its scalability, which is important from an industrial perspective and allows for a more reproducible and efficient production of pharmaceutical formulations. The aim of this study was to evaluate the effect of composition, mainly a fixed surfactant/cosurfactant (Smix) ratio, their concentration, and the parameters of high-pressure homogenization (HPH) processing on the quality and stability of ophthalmic fluconazole-loaded nanoemulsions. After a physicochemical analysis of nanoemulsions containing 20% w/w of oil, as optimal conditions for the HPH process, three cycles at a pressure of 1000 bar were established, obtaining formulations with an average droplet diameter size in the range of 80.63-129.68 nm and PDI values below 0.25. While it was expected that an increasing cosurfactant concentration decreased the droplet size, in the case of formulations containing Tween 20 and 10% w/w of cosurfactants, "over-processing" was observed, identified by the droplet size and polydispersity index increase. Consecutively, the selected formulations were evaluated for in vitro drug release in Franz's cell, antifungal activity, and 30-day stability using NMR spectroscopy. An antifungal activity test showed no significant difference in the antifungal activity between optimal fluconazole-loaded nanoemulsions and a 0.3% aqueous drug solution, but previously, research showed that prepared formulations were characterized by a higher viscosity and satisfactory prolonged release compared to a control. In a 30-day stability study, it was observed that higher HLB values of the used surfactants decreased the stability of the formulations in the following order: Kolliphor EL, Tween 80, Tween 20. The NMR spectra confirmed that Kolliphor EL-based formulations ensured the higher stability of the nanoemulsion composition in comparison to Tween 80 and a better stabilizing effect of propylene glycol as a cosurfactant in comparison to PEG 200. Therefore, the optimization of HPH technology should be focused on the selection of Smix and the Smix:oil ratio in order to prepare stable formulations of high quality.

Study of the surface properties of Alkyl-DEA from palmitic acid for cleaning and cosmetic applications

A surface active agent is a substance added to a liquid that is useful for increasing the spreading properties by weakening the surface tension of the liquid. The need for biosurfactants continues to increase along with industrial developments and increasing human awareness of good health and the environment. In this study, the surfactant alkyl diethanolamide (Alkyl-DEA) was synthesized using one type of amine alcohol, namely diethanolamine, through an amidation reaction between palmitic acid and using hexane-isopropanol solvent and calcium oxide catalyst. Surface properties in the form of acid number, saponification number, and HLB value were studied by observing the effect of the reaction variables on the three surface properties. This study showed that the best conversion of palmitic acid was obtained at 70oC and 80oC for a reaction time of 5 hours and a stirring speed of 150, 200, and 250 rpm. The relationship between reaction rate and time is directly proportional; the longer the reaction time, the reaction rate will increase. However, increasing the reaction time did not give significant results to the surfactant product. The relationship between reaction temperature and conversion gain decreased with increasing reaction temperature. The acid number obtained under the best conditions was 39.27, the saponification number was 30.85, and the HLB value was 4.29.

Effects of polymeric surfactants with low HLB values on drug and excipient release from self-emulsifying drug delivery systems

In this study, we evaluated the effects of polymeric surfactants with low hydrophile–lipophile balance values (PSLH) lauryl PEG-8 dimethicone (LP8D) and Pluronic L121 (P121) on drug and excipient release from self-emulsifying drug delivery systems (SEDDS). Valsartan (logKOW 1.5) was used as a model drug, whereas oleic acid (logKOW 7.64) was loaded in SEDDS as a model excipient. Diffusion of valsartan from oil phase to aqueous phase was significantly reduced when adding 5 % LP8D or P121 into the oil phase consisting of isopropyl myristate:Capmul MCM 4:1 m/m. Drug diffusion reached plateau phases after 72 h compared to 3 h in case of the non-PSLH oil phase. Adding 10 % either LP8D or P121 further decreased drug diffusion to aqueous phase. P121 showed a more controlled drug diffusion profile than LP8D at the same loading level. PSLH were loaded in SEDDS preconcentrates at different concentrations in the ranges of 0–15 % LP8D and 0–10 % P121 m/m to yield emulsion with size ∼200 nm and polydispersity index <0.3 upon dilution. The burst release phases from PSLH loaded SEDDS were suppressed and better controlled with higher PSLH loading ratios. The presence of PSLH in the oil phase could increase intermolecular interactions such as hydrogen bonding and London dispersion forces between PSLH and drug or excipient molecules as shown by FTIR difference spectra. Furthermore, PSLH can accumulate at the oil-water interfacial barrier and increase the activation energy level for solute molecules diffusion, i.e. adding 10 % LP8D led to a 3-fold increase in activation energy for oleic acid. Therefore, incorporation of PSLH in SEDDS formulation could be a potential approach to reduce drug diffusion coefficients, enhance drug affinity to oil phase and control drug release rate.

The Phase Inversion Mechanism of the pH-Sensitive Reversible Invert Emulsion.

Reversible emulsification drilling fluids can achieve conversion between oil-based drilling fluids and water-based drilling fluids at different stages of drilling and completion, combining the advantages of both to achieve the desired drilling and completion effects. The foundation of reversible emulsion drilling fluids lies in reversible emulsions, and the core of a reversible emulsion is the reversible emulsifier. In this study, we prepared a reversible emulsifier, DMOB(N,N-dimethyl-N'-oleic acid-1,4-butanediamine), and investigated the reversible phase inversion process of reversible emulsions, including the changes in the reversible emulsifier (HLB) and its distribution at the oil-water interface (zeta potential). From the perspective of the acid-alkali response mechanism of reversible emulsifiers, we explored the reversible phase inversion mechanism of reversible emulsions and reversible emulsification drilling fluids. It was revealed that the reversible phase inversion of emulsions could be achieved by adjusting the pH of the emulsion system. Then the proportion of ionic surfactants changed in the oil-water interface and subsequently raised/lowered the HLB value of the composite emulsifier at the oil-water interface, leading to reversible phase inversion of the emulsion. The introduction of organic clays into reversible emulsification drilling fluid can affect the reversible conversion performance of the drilling fluids at the oil-water interface. Thus, we also investigated the influence of organic clays on reversible emulsions. It was demonstrated that a dosage of organic clay of ≤2.50 g/100 mL could maintain the reversible phase inversion performance of reversible emulsions. By analyzing the microstructure of the emulsion and the complex oil-water interface, we revealed the mechanism of the influence of organic clay on the reversible emulsion. Organic clay distributed at the oil-water interface not only formed a complex emulsifier with surfactants, but also affected the microstructure of the emulsion, resulting in a difficult acid-induced phase transition, an easy alkali-induced phase transition, and improved overall stability.

The synthesis of certain fatty acid ester derivatives of trehalose and an investigation of their emulsifying properties and bioactivities

Bio-based surfactants exerting both functional and nutritional properties are needed in the food industry. This study reports the one-pot synthesis, using a Novozym 435-catalyzed trans-esterification protocol, of a new family of such compounds, namely a homologous series of 6-O-acylated trehalose and 6,6′-di-O-acylated trehalose derivatives incorporating long-chain fatty acid residues (12–22 carbons). These mono- and di-esters exhibited HLB values within the 8.3 to 14.7 range and their performance as surface-active compounds, penetration enhancers and anti-cancer agents have been evaluated. They were found to be excellent emulsifiers, maintaining oil-in-water emulsions with 566–742 nm mean oil-particle sizes and with the stability of these only gradually deteriorating over a 15-day storage period and during in vitro digestion. Mono-esters 2–4 embodying shorter side-chains (12–16 carbons) proved to be excellent foaming agents while congeners 4–6 incorporating longer side-chains (16–20 carbons) served as penetration enhancers capable of reversibly opening tight junctions in Caco-2 cell mono-layers. Mono-esters 5–7, as well as di-esters 11–13, exerted weak cytotoxic effects on seven human cancer cell lines. This work should serve as a useful guide for the development of the multi-functional properties of such trehalose esters in the food and related industries.

Investigation of effects of tropine-based surfactant structure on its thermal stability, foaming properties and solubilization

It has been shown that tropine-based ionic liquid surfactant (TILS) possesses exceptional biological, botanical, and pharmacological capabilities. Significantly, little research has been done on its essential characteristics, which are greatly influenced by its structural makeup. In this study, the essential properties, such as thermal stability, surface activity, foaming properties, and solubilization, were examined. The results demonstrate that the temperature stability of TILS was influenced by the nucleophilicity, coordination, and hydrophilicity of anions. Surface tension, solubility, and the HLB value of the TILS solution all worked together to affect the performance of the foam. The micellar and acid-base characteristics of TILS contributed to the solubilization of curcumin in its solution. The solubilization of curcumin in water was improved by TILS from 11 ng·mL−1 to more than 30 mgmmL−1, an increase of at least 106 times. These positive and adaptable physical and chemical characteristics highlight TILS potential in a variety of industrial-related applications.