Low Hydrophilic-lipophilic Balance Research Articles

Characterization of Porous β-Type Tricalcium Phosphate Ceramics Formed via Physical Foaming with Freeze-Drying.

Porous β-tricalcium phosphate (Ca3(PO4)2; β-TCP) was prepared via freeze-drying and the effects of this process on pore shapes and sizes were investigated. Various samples were prepared by freezing β-TCP slurries above a liquid nitrogen surface at -180 °C with subsequent immersion in liquid nitrogen at -196 °C. These materials were then dried under reduced pressure in a freeze-dryer, after which they were sintered with heating. Compared with conventional heat-based drying, the resulting pores were more spherical, which increased both the mechanical strength and porosity of the β-TCP. These materials had a wide range of pore sizes from 50 to 200 µm, with the mean and median values both approximately 100 µm regardless of the freeze-drying conditions. Mercury porosimetry data showed that the samples contained small, interconnected pores with sizes of 1.24 ± 0.25 µm and macroscopic, interconnected pores of 25.8 ± 4.7 µm in size. The effects of nonionic surfactants having different hydrophilic/lipophilic balance (HLB) values on foaming and pore size were also investigated. Materials made with surfactants having lower HLB values exhibited smaller pores and lower porosity, whereas higher HLB surfactants gave higher porosity and slightly larger macropores. Even so, the pore diameter could not be readily controlled solely by adjusting the HLB value. The findings of this work indicated that high porosity (>75%) and good compressive strength (>2 MPa) can both be obtained in the same porous material and that foaming agents with HLB values between 12.0 and 13.5 were optimal.

An Experimental Study on the Performance and Emissions of an 8% Water-in-Diesel Emulsion Stabilized by a Hydrophilic Surfactant Blend

Diesel engines are known for their excellent efficiency and are therefore used in a variety of applications. However, they are also one of the main sources of hazardous emissions such as nitrogen oxides (NOx) and smoke. Water-in-Diesel Emulsion (WiDE) is an alternative fuel that can possibly reduce some of the pollutant emissions without compromising engine performance. The surfactant formulation for WiDE usually follows the one used in water-in-oil (w/o) emulsions, where low hydrophilic–lipophilic balance (HLB) emulsifiers are preferred for better solubility in the diesel phase and stabilization at storage temperatures. However, by using a hydrophilic blend with a non-ionic surfactant, it is possible to develop an optimized formulation at higher fuel temperatures, which occur during an engine’s operating condition, achieving possibly higher benefits. Across the different speeds, the results for the emulsion show 7.57% mean improvement in specific fuel consumption (SFC), 19.14% mean improvement in thermal efficiency (TE), 5.54% mean reduction in carbon dioxide (CO2), 20.50% mean reduction in nitric oxide (NO) and 75.19% mean reduction in smoke levels. However, carbon monoxide (CO) and hydrocarbons (HC) emissions were higher, with a mean increase of 81.09% and 93.83%, respectively.

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.

Effects of surfactants on extra virgin coconut oil-in-water microemulsion formation and properties for topical application

The formation and properties of oil-in-water microemulsion prepared from extra virgin coconut oil (EVCO) can be affected with the combination of different surfactants. In this study, Tween 80, PEG 400 and Span 85 were studied for their effects on the formation of microemulsion, pH, viscosity and phase separation. The three surfactants were first screened for their ability to form oil-in-water microemulsion either alone or at a combination ratio of 1:1. Formulation of F6 sample used the combination of Tween 80:PEG 400 at ratio 2:1 and was performed at much lower concentration of surfactants to reduce any skin irritation risks related to the use of high surfactant concentration. The results revealed that all F1-F6 samples were oil-in-water microemulsions except F3 sample which had lower hydrophilic-lipophilic balance (HLB), thus forming water-in-oil microemulsion. The F6 samples were translucent whereas all other 5 samples were transparent. The smaller particle sizes of 12.0–––27.7 nm of F6 samples could be associated with the high surfactant-to-oil ratio of 9:1. The low viscosity of < 20 cP obtained for F1, F4 and F6 samples suggests that these samples may promote higher transdermal flux when applied onto the skin. All samples except F1 and F3 showed pH in the range of 4 – 6, which supports these formulations for topical application. From the findings, it can be suggested that the combination of surfactants with different hydrophilic-lipophilic balance (HLB) have different effects on the formation of extra virgin coconut oil-in-water microemulsion and their physicochemical properties.

Mechanism for adjusting the strength of interphase adsorption layers of "Skimmed milk – surfactant substance" in dessert products

Today, the range of dessert products produced by the restaurant industry of Ukraine is wide and diverse and is determined by its nomenclature. Mousse is one of the most common dessert dishes ordered in restaurants of various levels. The traditional technological scheme of mousses production is to some extent labor-intensive, and this makes it difficult to satisfy consumer demand. Therefore, the use of a dry mixture in the recipe composition of mousses is justified. This article is devoted to the investigating the regulatory mechanisms of interphase adsorption layer strength at the interface of the water – oil and water – air phases by introducing surfactants into the dry mixture for the manufacture of dessert products. The choice of surfactants and their concentrations for the formation of interfacial adsorption layers in systems is based on the consideration of surface activity, hydrophilic-lipophilic balance (HLB) and protein concentration, which determines the behavior of the mixture of surfactants in the system. The issue of the influence of surfactants with high and low HLB and their mixtures and the use of a system with three surfactants E472e-E472b-E322, which allow to obtain whipped emulsions from a dry mixture, are considered.

MECHANISM FOR ADJUSTING THE STRENGTH OF INTERPHASE ADSORPTION LAYERS OF "SKIMMED MILK – SURFACTANT SUBSTANCE" IN DESSERT PRODUCTS

Today, the range of dessert products produced by the restaurant industry of Ukraine is wide and diverse and is determined by its nomenclature. Mousse is one of the most common dessert dishes ordered in restaurants of various levels. The traditional technological scheme of mousses production is to some extent labor-intensive, and this makes it difficult to satisfy consumer demand. Therefore, the use of a dry mixture in the recipe composition of mousses is justified. This article is devoted to the investigating the regulatory mechanisms of interphase adsorption layer strength at the interface of the water–oil and water–air phases by introducing surfactants into the dry mixture for the manufacture of dessert products. The choice of surfactants and their concentrations for the formation of interfacial adsorption layers in systems is based on the consideration of surface activity, hydrophilic-lipophilic balance (HLB) and protein concentration, which determines the behavior of the mixture of surfactants in the system. The issue of the influence of surfactants with high and low HLB and their mixtures and the use of a system with three surfactants E472e-E472b-E322, which allow to obtain whipped emulsions from a dry mixture, are considered.

Effect of Surfactant Formula on the Film Forming Capacity, Wettability, and Preservation Properties of Electrically Sprayed Sodium Alginate Coats.

Surfactants are always added to coating formulations to ensure good adhesion of edible coatings to a product's surface and to maintain freshness. In this study, the effects of the mix surfactants Tween 20 and Span 80 with different hydrophile-lipophile balance (HLB) values on the film-forming ability, wettability, and preservation capacity of blueberry sodium alginate coating were investigated. The results indicated that Tween 20 obviously ensured favorable wettability and improved the uniformity and mechanical properties of the resulting film. While the addition of Span 80 reduced the mean particle size of the coating, enhanced the water resistance of the film, and helped to reduce blueberry weight loss. A sodium alginate coating with low viscosity and medium HLB could better inhibit the galactose, sucrose, and linoleic acid metabolism of blueberries, reduce the consumption of phenols, promote the accumulation of flavonoids, and thus display superior coating performance. In summary, sodium alginate coating with medium HLB had comprehensive advantages in film-forming ability and wettability and was conducive to the fresh-keeping role.

Effect of hydrophilic/lipophilic balance on the porogenic properties of non-ionic surfactants for monolith preparation and chromatographic separation

The effect of hydrophilic/lipophilic balance (HLB) of polyoxyethylene ethers of different chain lengths on the microporogenic properties of the Brij surfactants has been studied. The objective of this work is to help better understand the role of each porogen and to set criteria for selecting the proper non-ionic surfactant, based on the HLB value. Seven recipes of different porogen compositions were first prepared and the highest efficiency was achieved using decane/decanol/dodecanol mixture with Brij® 30. Then, four other Brij surfactants covering the entire HLB scale were tested, and the prepared monoliths were characterized by SEM, BET, FT-IR and chromatography. The results showed that increasing the HLB from 9.72 to 18.84 was accompanied by an increase in monolith density and surface areas. The optimum HLB range was found to be 10 to 15. Surfactants of lower HLB formed either nonporous or less efficient columns, while those of higher HLB formed non-permeable columns. Adjusting the HLB was possible by mixing surfactants of different HLB. The prepared monoliths could be used in the isocratic mode with a mobile phase consisting of a mixture of ACN and water (20:80, v/v) at a flow rate of 1.5 μL min−1 to separate five sulfa drugs. The separation results showed that the elution order of the compounds correlated with their lipophilicity, with sulfamerazine (logp = 0.52) being the first to elute, and sulfaquinoxoline (logp=1.70) being the most retained. The asymmetry factors of the separated compounds ranged between 1.18 and 1.25, and the resolution was found to be in the range 2.92−7.80. The prepared monoliths could be also successfully separate a mixture of four different nonsteroidal anti-inflammatory drugs and a mixture of four benzoic acid derivatives. This work assists in optimizing the surfactant-based porogenic mixture to meet the desired porosity, surface area, morphology and chromatographic separation requirements.

Recent Trends in Improving the Oxidative Stability of Oil-Based Food Products by Inhibiting Oxidation at the Interfacial Region

In recent years, new approaches have been developed to limit the oxidation of oil-based food products by inhibiting peroxidation at the interfacial region. This review article describes and discusses these particular approaches. In bulk oils, modifying the polarity of antioxidants by chemical methods (e.g., esterifying antioxidants with fatty alcohol or fatty acids) and combining antioxidants with surfactants with low hydrophilic-lipophilic balance value (e.g., lecithin and polyglycerol polyricinoleate) can be effective strategies for inhibiting peroxidation. Compared to monolayer emulsions, a thick interfacial layer in multilayer emulsions and Pickering emulsions can act as a physical barrier. Meanwhile, high viscosity of the water phase in emulsion gels tends to hinder the diffusion of pro-oxidants into the interfacial region. Furthermore, applying surface-active substances with antioxidant properties (such as proteins, peptides, polysaccharides, and complexes of protein-polysaccharide, protein-polyphenol, protein-saponin, and protein-polysaccharide-polyphenol) that adsorb at the interfacial area is another novel method for enhancing oil-in-water emulsion oxidative stability. Furthermore, localizing antioxidants at the interfacial region through lipophilization of hydrophilic antioxidants, conjugating antioxidants with surfactants, or entrapping antioxidants into Pickering particles can be considered new strategies for reducing the emulsion peroxidation.

Effect of alcohols on water solubilization in surfactant-free diesel microemulsions

Microemulsions are preferred over other methods of mixing two immiscible liquids as they are thermodynamically stable, but require a high percentage of surfactant. Surfactant-free microemulsions, on the other hand, use an amphisolvent instead of surfactants, making them an economical alternative. The current experimental investigation focuses on formulation of surfactant-free water-in-diesel microemulsions with the help of straight-chain aliphatic alcohols as diesel replacement for IC engines. Dynamic light scattering measurements revealed these microemulsions had average water droplets of less than 10 nm. The microemulsions were formulated using single-alcohol, two-alcohols, and three-alcohols. It becomes crucial to study the water solubilization of microemulsions as the addition of water in diesel improves combustion efficiency. The water solubilization in surfactant-free microemulsions was found to be dependent on the hydrophilic–lipophilic balance (HLB) of the alcohols, as it determined the solubilizing property of alcohol. The microemulsions could only be formulated in the HLB range of 6.27 to 7.76 and were found to have maximum water solubilization in the HLB range of 6.67 to 7.63. Butanol had the highest water solubilization in a single alcohol system, butanol–ethanol in the ratio of 3:1 for the two-alcohol system, and propanol–butanol–octanol in the ratio of 3:1:1 for three-alcohol systems. Alcohols with higher HLB were more hydrophilic, causing migration of alcohol from the interface to bulk water. In comparison, alcohol with a lower HLB caused the migration of alcohol from the interface to bulk diesel, which resulted in reduced water solubilizations. Hence, the microemulsions could not be formulated beyond specific HLB range. The formulated microemulsions could be a prospective substitute for diesel fuel as alcohols can be derived from renewable routes.

Effect of hydrophile–lipophile balance of the linker in Gal/GalNAc ligands on high-affinity binding of galactosylated liposomes by the asialoglycoprotein receptor

In this study, we explored the effect of the hydrophile–lipophile balance (HLB) in the linker unit of Galactose (Gal)/N-acetylgalactosamine (GalNAc) ligands on their affinity toward asialoglycoprotein receptors (ASGPRs). Two Gal/GalNAc ligands with lipophilic linkers—{(5-cholesten-3b-ol)[(2-acetamido-2-deoxy-d-galactopyranose-6-o)sebacate]} (CHS-6-GalNAc) and {(5-cholesten-3b-ol)[(d-galactopyranose-6-o)sebacate]} (CHS-6-Gal)—and two with hydrophilic linkers—{(5-cholesten-yl)[(4-O-b-D-galactopyranosyl)-D-glucitol-6-yl]sebacate} (CHS-1-Gal) and {(5-cholesten-3a-ol)[(2-acetamido-2-deoxy-d-galactopyranose-6-o)3,6-dioxa-octanedioate]} (CHS-PEG2-6-GalNAc)—were synthesized by enzymatic catalysis. Compared with unmodified liposomes, all Gal/GalNAc ligand–modified liposomes showed higher efficiency toward the hepatocyte target as evaluated by weighted-average overall drug-targeting efficiency (Te*) in vivo and HepG2 cell uptake efficiency in vitro. The ligands containing linkers with high HLB values (i.e., CHS-PEG2-6-GalNAc and CHS-1-Gal) exhibited higher ASGPR affinity than those containing linkers with low HLB values (i.e., CHS-6-GalNAc and CHS-6-Gal). We used molecular-dynamics (MD) simulations to investigate the structure–activity relationship between the HLB value of the linker in a ligand and ASGPR affinity. MD simulation results indicated that a Gal/GalNAc ligand with a more hydrophilic linker (i.e., higher HLB value) unit tended to have a higher solvent-accessible surface area (SASA), leading to lower steric hindrance for effective ASGPR recognition. The results of this study will provide an improved design for Gal/GalNAc ligand–based surface-modified liposomes with high ASGPR affinity.

Surfactant membranes architecture and performance: Effect of HLB value and concentration of non-ionic surfactants

This paper discusses a pioneering work on the effect of hydrophilic-lipophilic balance (HLB) values and non-ionic surfactant concentrations on the performance, architecture i.e. morphology and molecular orientation of polyethersulfone/polyether glycol (PES/PEG 600) for surfactant membrane. PES surfactant membranes were developed through phase inversion fabrication technique with the addition of non-ionic surfactants Triton X-100 (TX100) and Tween 20 (T20) into the polymer solution during formulation. The results of the experimental data conducted showed that 2 wt% increase in the concentration of non -ionic surfactants resulted increased in pure water permeated (PWP) flux and salt solution flux. T20 at 3 wt%, the surfactant membrane reached an highest PWP level of around 1200.67 L/m2 × h while showing an highest flux obtained at 31,692 L/m2 x h. Analysis of membrane structure construction from the morphological results of 3 wt% TX100 membrane having lower HLB value yielded highest rejection at 99.7% and became a booster to produce fine membrane structure, subsequently producing high performance surfactant membrane.

Contrasting impacts of mixed nonionic surfactant micelles on plant growth in the delivery of fungicide and herbicide

HypothesisNonionic alkyl ethoxylate surfactants are widely used in agrochemicals to facilitate the permeation of systemic herbicides and fungicides across the plant waxy film. Industrial grade surfactants are often highly mixed and how the mixing affects their interactions with pesticides and wax films remains largely unexplored. A better understanding could enable design of mixed nonionic surfactants for herbicides and fungicides to maximize their efficiency and reduce wastage whilst controlling their impact on plant wax films. ExperimentIn this study, nonionic surfactants with general structure n-oxyethylene glycol monododecyl ether (C12En) were used to form surfactant mixtures with the same average ethoxylate numbers but different hydrophilic-lipophilic balance (HLB) values. Their mixed micellar systems were then used to solubilize a herbicide diuron (DN) and a fungicide cyprodinil (CP), followed by plant wax solubilization upon contact with wax films. These processes were monitored by 1H NMR and SANS. FindingPesticide solubilization made surfactant micelles effectively more hydrophobic but subsequent wax dissolution caused pesticide release and the restoration of the micellar amphiphilicity. Nonionic surfactants with lower HLBs form larger nanoaggregates, show enhanced wettability, and have better ability to solubilize and permeate pesticides across the wax film, but may cause significant damage to plant growth. These observations help explain why herbicides applied on weeds would benefit from surfactants with lower HLB values while fungicides require surfactants with HLBs to balance between delivery efficiency and potential phytotoxicity risks.

Hemolytic Response of Iron Oxide Magnetic Nanoparticles at the Interface and in Bulk: Extraction of Blood Cells by Magnetic Nanoparticles.

Surface-active and water-soluble magnetic nanoparticles (NPs) were synthesized in the presence of a series of amphiphilic molecules of different functional groups to determine the hemolytic response and their ability to extract blood cells across the interface and aqueous bulk while maintaining minimum hemolysis. Amphiphilic molecules such as Gemini surfactants of strong hydrophobicity and low hydrophilic-lipophilic balance produced surface-active magnetic NPs, which were highly cytotoxic even when placed at the blood suspension (aqueous)-air interface. A similar behavior was shown by water-soluble magnetic NPs produced using monomeric ionic and nonionic surfactants and different amino acids. The NPs produced using mild biological surfactants and mono- and oligosaccharides of the same functional group proved to be excellent blood cell extractors with minimum hemolysis. α/β-cyclodextrin and dextrose-stabilized magnetic NPs induced negligible hemolysis and extracted more than 50% of blood cells. The results showed that nontoxic magnetic NPs are excellent blood cell extractors from the blood suspension when tagged with amphiphilic molecules possessing good biocompatibility with cell membranes without inducing hemolysis. The work highlights the biological applicability of nontoxic magnetic NPs at biointerfaces and in blood suspensions.

One step surfactant entrapment onto PVDF hollow fiber membrane surface by the TIPS process using a triple-layer orifice spinneret

One step entrapment of the several kinds of surfactants on the outer surface of the PVDF hollow fiber membrane during the air gap distance was studied by extruding the surfactant solution as the outermost layer of the triple layer nozzle via thermally induced phase separation (TIPS) process. Effect of the membrane preparation conditions, including the air gap distance, surfactant concentration and types of surfactant with different hydrophilic-lipophilic balance (HLB) number and molecular weight on the membrane surface hydrophilicity and protein fouling resistance were evaluated. Using a long air gap distance with optimal surfactant concentration was resulted in a membrane with a considerable improvement in hydrophobicity. Surfactants with the lowest HLB number and molecular weight improved membrane hydrophilicity and resistance against pure water permeability decrease after drying membrane in air. Based on water contact angle results, entrapment of the surfactant with a more hydrophobic segment to hydrophilic segment ratio (smaller HLB) plays a crucial role to increase the membrane surface hydrophilicity regardless the intrinsic hydrophilicity of the surfactant molecule. The stability of the surfactant entrapped by this method was higher than that of the simple coating method. Static adsorption of the lysozyme on the surface of the surfactant entrapped membrane was in line with water contact angle results. Thus, entrapping surfactants with low HLB number and molecular weight was recommended to obtain a membrane with the considerable anti-fouling property.

Breaking water-in-oil emulsion of Northern Iraq’s crude oil using commercial polymers and surfactants

Water (W) and oil (O) normally mix during production and while passing through valves and pumps to form a persistent water-in-oil (W/O) emulsion, which is a serious restriction in oil production and transporting and refining processes. The objective of this work is to treat emulsions of two crude oil samples labeled KD1 and DGH2 using commercial polymers and surfactants which are also known as demulsifiers. Hydrophile–lipophile balance (HLB) in the demulsifier structure has demonstrated a great effect on breaking W/O emulsion. Emulsion breakers with low HLB value showed better reduction in the dynamic IFT, high diffusivity at the W/O interface, and accelerated coalescence of water droplets. Concomitantly, high emulsion temperatures were found to reduce the interfacial film viscosity and accelerate water droplets coalescence. A maximum water separation efficiency (WSE) of 97% was achieved in the case of KD1 and 88% for DGH2, and using a (1:1) polymer blend demulsifier further increased WSE to 99% after 100 min.

INHIBITORY EFFECT OF ASCORBIC ACID MICROEMULSION ON PHOTO-OXIDIZED VIRGIN COCONUT OIL

The effect of water-in-oil (w/o) microemulsion containing ascorbic acid on photo-oxidative stability of virgin coconut oil (VCO) was investigated. To optimize the formulation, w/o microemulsions were prepared using hydrophilic lipophilic balance (HLB) concept, consisted of ternary nonionic surfactants having low, medium, and high HLB values. From this optimum HLB number, the ratio of water, surfactant and oil was determined to obtain microemulsion areas. After optimization of the microemulsion system, the storage at room temperature, and the extreme condition were conducted for testing the microemulsion stability. Then, the stable formulas were used for delivering ascorbic acid. The solubility and photo-oxidative stability of ascorbic acid microemulsion were evaluated. The optimum formula of ascorbic acid microemulsion was applied into VCO at various concentrations (0, 1, 5, and 10% w/w). Samples were subjected to photo-oxidation under fluorescent light exposure of 4000 lux for up to 8 hours. Peroxide values (PVs) and p-anisidine values (p-AnVs) of the samples were measured at 1 hour interval. The results indicated that w/o microemulsion could be formed on the HLB number of 7. W/o microemulsion containing 75% oils need surfactant concentrations of ≥ 4.5 part of water, and if containing 77.78% oils, the surfactant concentration must ≥ 5.5 part of water. These microemulsions remained stable during storage at room temperature, even after centrifugation, but did not tolerate at high temperature. The maximum solubility of ascorbic acid in w/o microemulsion was 1%. Ascorbic acid microemulsion resistant to photo-oxidation and effective inhibits that reaction in VCO. This study confirmed that w/o microemulsion can act as ascorbic acid delivery system to disperse into VCO for inhibiting its’ quality deterioration due to photo-oxidation.

INHIBITORY EFFECT OF ASCORBIC ACID MICROEMULSION ON PHOTO-OXIDIZED VIRGIN COCONUT OIL

The effect of water-in-oil (w/o) microemulsion containing ascorbic acid on photo-oxidative stability of virgin coconut oil (VCO) was investigated. To optimize the formulation, w/o microemulsions were prepared using hydrophilic lipophilic balance (HLB) concept, consisted of ternary nonionic surfactants having low, medium, and high HLB values. From this optimum HLB number, the ratio of water, surfactant and oil was determined to obtain microemulsion areas. After optimization of the microemulsion system, the storage at room temperature, and the extreme condition were conducted for testing the microemulsion stability. Then, the stable formulas were used for delivering ascorbic acid. The solubility and photo-oxidative stability of ascorbic acid microemulsion were evaluated. The optimum formula of ascorbic acid microemulsion was applied into VCO at various concentrations (0, 1, 5, and 10% w/w). Samples were subjected to photo-oxidation under fluorescent light exposure of 4000 lux for up to 8 hours. Peroxide values (PVs) and p-anisidine values (p-AnVs) of the samples were measured at 1 hour interval. The results indicated that w/o microemulsion could be formed on the HLB number of 7. W/o microemulsion containing 75% oils need surfactant concentrations of ≥ 4.5 part of water, and if containing 77.78% oils, the surfactant concentration must ≥ 5.5 part of water. These microemulsions remained stable during storage at room temperature, even after centrifugation, but did not tolerate at high temperature. The maximum solubility of ascorbic acid in w/o microemulsion was 1%. Ascorbic acid microemulsion resistant to photo-oxidation and effective inhibits that reaction in VCO. This study confirmed that w/o microemulsion can act as ascorbic acid delivery system to disperse into VCO for inhibiting its’ quality deterioration due to photo-oxidation.

Lightweight structural eco-mortars made with polyurethane wastes and non-Ionic surfactants

The properties of structural lightweight mortars obtained with recovered foam polyurethane wastes have been studied, containing a low fraction of soluble non-ionic surfactant. The characterisation of mechanical properties, bulk density, microstructure and porosity highlights two types of behaviour according to the composition (e.g. hydrolysis grade) of the non-ionic surfactants. By using additives with low hydrophilic–lipophilic balance (HLB) values, the lightweight mortars show more and more high mechanical properties according to the increase of the substitution rate of sand by PU wastes. These non-ionic surfactants seem to promote a homogeneous microstructure and improve the adhesion between PU wastes and cement paste. On the other hand, the mortars mixed with additives showing high HLB values, are more lightweight and macroporous, due to the increase of air entrained driven by the substitution rate of sand by PU wastes.

Experimental investigation of coal dust wetting ability of anionic surfactants with different structures

Abstract To better understand the coal dust wetting ability of anionic surfactants with different structures, sodium dodecyl sulfate (SDS), sodium dodecyl sulfonate (SDDS), and sodium dodecyl benzene sulfonate (SDBS) were selected. The surface tension, wetting time, and infrared spectra of coal dust were tested. The hydrophilic-lipophilic balance (HLB) values of the surfactants were calculated. Results showed that the decrease in the surface tension could shorten the wetting time at low surfactant concentrations. But the decrease in the wetting time was no longer related to the constant surface tension that was lower than 45 mN/m. The adsorption density depends on the hydrophobic interactions and electrostatic repulsions between the surfactant molecules and the coal dust. During the dynamic immersion process, the surfactants with high HLB values could bring the coal dust into the bulk solution rapidly. The wetting time of coal dust for SDBS with a high adsorption density and low HLB or SDS with a small adsorption density and high HLB was relatively longer. The adsorption density and HLB value of SDDS were intermediate between those of SDS and SDBS. Under the combined action of these two factors, the wetting time of SDDS was shorter than those of SDS and SDBS.