Hydrophile-lipophile Balance Number Research Articles

Degreasing Efficiency of Electroplating Pretreatment Process Using Secondary Alcohol Ethoxylate as Nonionic Surfactant

In this study, the effect of the hydrophilic–lipophilic balance (HLB) number and cloud point (CP) of a secondary-alcohol ethoxylated nonionic surfactant on degreasing efficiency was investigated. A degreasing process was conducted for steel samples with different surfactants in a degreasing solution. The HLB number and CP increased with the increasing n of the hydrophilic ethylene oxide (OCH2CH2)n group. For a constant temperature of the degreasing solution (30–80 °C), the degreasing efficiency was investigated as a function of degreasing time. The highest degreasing efficiency was observed near the cloud point of the surfactant, and the degreasing efficiency decreased significantly at temperatures lower and greater than the cloud point. A Hogaboom test was carried out to observe oil stains on the surface of samples. Additionally, the contact angle of the surface with water droplets was measured after degreasing with various surfactants.

Influence of the length of the spacer group on the performance of the sulfate-based Gemini surfactants

PurposeA series of sulfate-based Gemini anionic surfactants were synthesized via etherification, ring opening and sulfation reactions using epichlorohydrin, fatty alcohol, ethylene glycol and chlorosulfonic acid as the main raw materials. Orthogonal experiments for 1,8-bisalkoxymethylene-3,6-dioxin-1,8-octane disulfate were performed on the sulfation reaction to determine the optimal reaction conditions.Design/methodology/approachA series of sulfate-based Gemini anionic surfactants were synthesized via etherification, ring opening and sulfation reactions using epichlorohydrin, fatty alcohol, ethylene glycol and chlorosulfonic acid as the main raw materials. Orthogonal experiments for 1,8-bisalkoxymethylene-3,6-dioxin-1,8-octane disulfate were performed on the sulfation reaction to determine the optimal reaction conditions. The structures of the intermediate and final products were characterized by FT-IR (Fourier transform infrared spectroscopy analysis), 1H-NMR (proton nuclear magnetic resonance spectroscopy) methods. The thermal performance of surfactants was analyzed using thermogravimetric analysis (TGA). The thermogravimetric results showed that the sulfate-based Gemini surfactants had good heat resistance (the thermal decomposition temperature of which was in the range of 140∼170?). The Krafft point, surface tension, foaming, Hydrophile–Lipophile Balance Number (HLB), emulsifying, wetting, and lime-soap dispersing performance were measured by visual observation, hanging drop method, aqueous surfactant solution method and Borghetti–Bergman method, respectively. The results have shown that all the sulfate-based Gemini surfactants had good water solubility and lime-soap dispersing ability. When spacer group was -(CH2)2-, with the increase of the carbon chain length from C12 to C14, the micellar concentration critical micelle concentration and surface tension (CMC) gradually increased from 8.25 × 10–4 mol/L to 8.75 × 10–4 mol/L and 27.5 mN/m to 30.9 mN/m, respectively. Also, the sulfate-based Gemini surfactants with the different length of the spacer group had a different effect on their performance on foaming properties and foam properties, HLB and emulsifying ability and wetting ability. FindingsIn view of the important role of the spacer group and the general use of anionic surfactants in oil fields, this article considers the preparation of a series of sulfate-based Gemini surfactants by changing the spacer group and the chain length of the hydrophobic group and evaluating their surface activity, and finally its Kraffi, on the foam properties, HLB value, emulsifying performance, lime soap dispersing ability etc.Originality/valueSulfate-based Gemini surfactants have broad application prospects in the fields of oil and gas exploitation, environmental protection, chemistry and daily chemical industry and so on.

Surface Properties and Liquid Crystal Properties of Alkyltetra(oxyethyl) β-d-Glucopyranoside.

Hydrophilic alkyl polyglycosides (APGs) and alkyl glycosides (AGs) with anomeric pure are a class of important substitutes for petroleum-based surfactants. Improving their water solubility should make such hydrophilic glycosurfactants have more excellent potential application value. To solve the inherent problem of poor water solubility of traditional alkyl β-d-glucopyranoside (5), a series of alkyltetra(oxyethyl) β-d-glucopyranosides (4a-4g, n = 7-18) were successfully synthesized by introducing tetra(oxyethylene) fragments to carry out the structural modification. The relationship between the related structure and the physicochemical properties was further investigated, including their hydrophilic-lipophilic balance (HLB), water-solubility, foaming performance, emulsification, hygroscopicity, surface activity, and thermotropic/lyotropic liquid crystal phase behavior. The results showed that the water solubility gradually decreased as the alkyl chain length increased due to the gradual decrease of their HLB number. Octadecyltetra(oxyethyl) β-d-glucopyranoside (4g, n = 18) was found to be insoluble in water at 25 °C. Taken together, long-chain alkyl glycosides had good foaming properties and excellent emulsifying properties. Among them, dodecyltetra(oxyethyl) β-d-glucopyranoside (4d, n = 12) had the best foaming performance. In the rapeseed oil/water system, cetyltetra(oxyethyl) β-d-glucopyranoside (4f, n = 16) had the best emulsifying ability. With the increase of the alkyl chain length, the critical micelle concentration (Ccmc), γcmc, Γmax, and hygroscopicity of this series of glycosides showed a downward trend. Differential scanning calorimetry (DSC) and polarizing optical microscopy (POM) showed that the thermal stability increased with the increase of the alkyl chain length, and alkyltetra(oxyethyl) β-d-glucopyranosides (4d-4g, n = 12-18) had the corresponding melting points and clearing points. Alkyltetra(oxyethyl) β-d-glucopyranosides (4b-4g, n = 8-18) formed a smectic phase with a typical fan-shaped and focal conic texture during the cooling process. In the water contact experiments, it was found that glycosides (4b-4g, n = 8-18) at high concentrations transformed into various lyotropic liquid crystal including hexagonal phase, bicontinuous cubic phase, and lamellar phase phases. Therefore, such green nonionic glycosurfactants alkyltetra(oxyethyl) β-d-glucopyranosides should have potential practical application prospects.

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.

Water Solubility and Surface Property of Alkyl Di-/Tri-/Tetraoxyethyl β-d-Xylopyranosides.

Alkyl di-/tri-/tetraoxyethyl β-d-xylopyranosides as derivatives of alkyl xylosides are a class of non-ionic sugar-based surfactants. They were stereoselectively synthesized by the Helferich method. Their properties including hydrophilic-lipophilic balance number, water solubility, surface property, foam property, emulsifying property, and thermotropic liquid crystal property were mainly investigated. The results showed that their water solubility decreased with increasing the alkyl chain length and increasing the number of the oligooxyethyl fragment. The critical micelle concentration had a monotonous decreasing trend with increasing the alkyl chain length. Nonyl di-/tri-/tetraoxyethyl β-d-xylopyranosides [-(OCH2CH2)m-, where m = 2, 3, and 4] exhibited the most excellent foaming ability and foam stability. In the n-octane/water system, dodecyl tetraoxyethyl β-d-xylopyranosides and tetradecyl tetraoxyethyl β-d-xylopyranosides had the strongest emulsion ability. In addition, some alkyl di-/tri-/tetraoxyethyl β-d-xylopyranosides had thermotropic liquid crystal properties. Such sugar-based surfactants, alkyl di-/tri-/tetraoxyethyl β-d-xylopyranosides, will be expected to develop for a variety of practical application.

Solution Properties of Alkyl β‐D‐Maltosides

AbstractAlkyl β‐D‐maltosides are an important class of sugar‐based nonionic surfactants and have been widely studied. Nevertheless, it is still necessary to investigate further their amphiphilic structure‐surface property relationships. In this article, we reported a series of properties of synthetic alkyl β‐D‐maltosides (6a–6i, n = 6–18) including their hydrophilic–lipophilic balance (HLB) number, water solubility, hygroscopicity, moisture‐retention capacity, foaming ability, surface tension, thermotropic phase behavior, and skin irritation. Their HLB number and water solubility decreased with increasing alkyl chain length. Hexyl β‐D‐maltoside exhibited the strongest hygroscopicity and moisture‐retention capacity. Decyl β‐D‐maltoside and dodecyl β‐D‐maltoside possessed excellent foaming power and foaming stability. Furthermore, the critical micelle concentration (CMC) of alkyl β‐D‐maltoside (6a–6g, n = 6–14) and their surface tension at CMC decreased with increasing alkyl chain length. At last, alkyl β‐D‐maltosides (6a–6g) should be considered as safe surfactants by the skin irritation assessment.

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.

An efficient method to determine the Hydrophile-Lipophile Balance of surfactants using the phase inversion temperature deviation of Ci Ej /n-octane/water emulsions.

The aim of this study was to develop a fast and an efficient method to determine the Hydrophile-Lipophile Balance (HLB) number of cosmetic and pharmaceutics surfactants. This method is based on the deviation of the phase inversion temperature induced by the addition of the test compound, with respect to the phase inversion temperature of a reference system, which includes an ethoxylated surfactant. This method is called PIT-deviation. Three calibration curves are set up with three reference ethoxylated surfactants. These calibration curves make it possible to evaluate the interfacial behaviour of certain chemicals. More particularly, these curves make it possible to easily determine the surfactant HLB. In this study, a fast and accurate method has been developed to determine the hydrophilic-lipophilic balance (HLB) number of amphiphilic chemicals. This new method can be applied to establish an HLB number of all commercial amphiphilic ingredients. Compounds which have a PIT-deviation close to zero are also discussed.

Synthesis and Properties of Alkoxyethyl β‐d‐Xylopyranoside

AbstractIn order to improve the water solubility of sugar‐based surfactants, alkyl β‐d‐xylopyranosides, novel sugar‐based surfactants, 1,2‐trans alkoxyethyl β‐d‐xylopyranosides, with alkyl chain length n = 6–12 were stereoselectively prepared by the trichloroacetimidate method. Their properties including hydrophilic–lipophilic balance (HLB) number, water solubility, surface tension, emulsification, foamability, thermotropic liquid crystal, and hygroscopicity were investigated. The results indicated that their HLB number decreased with increase of alkyl chain, the water solubility improved since the hydrophilic oxyethene (─OCH2CH2─) fragment was introduced. The dissolution process was entropy driven at 25–45 °C for alkyl chain length n = 6–10. Octyloxyethyl β‐d‐xylopyranoside had the best foaming ability. Nonyloxyethyl β‐d‐xylopyranoside had the best foam stability and the emulsifying ability was better in toluene/water system than in rapeseed oil/water system. The surface tension of in aqueous solution dropped to 27.8 mN m−1 at the critical micelle concentration, and it also showed the most distinct thermotropic liquid phases with cross pattern texture upon heating and the fan schlieren texture on cooling. Hexyloxyethyl β‐d‐xylopyranoside possessed the strongest hygroscopicity. Based on the effective improvement of water solubility, the prepared alkoxyethyl β‐d‐xylopyranosides showed excellent surface activity and are expected to develop their practical application as a class of novel sugar‐based surfactants.

Response of Workers to Polyoxyethylene Tridecyl Ether Surfactants in Relation to Hydrophilic-lipophilic Balance

Surfactants are commonly used in insecticide formulations as adjuvants to enhance the performance of the insecticidal active ingredients. However, surfactants may have their own intrinsic detrimental effect on insects. In this study, the responses of red imported fire ants, Solenopsis invicta Buren, to 6 polyoxyethylene tridecyl ether surfactants (Ethal TDA) and their relationships to the hydrophilic-lipophilic balance (HLB) numbers were investigated in topical, glass-vial and immersing bioassays. In topical and glass-vial bioassays, significant linear dependence of ant mortality on HLB number was detected and the mortality was negatively related to HLB number. In immersing bioassay, a fast immobilizing effect was observed; however, the time needed to immobilize ants was not related to HLB number in most cases. In conclusion, Ethal TDA surfactants have intrinsic toxicity against S. invicta workers and ant mortality in both topical and glass-vial bioassays was negatively related to their HLB numbers.

A comparison of physicochemical and functional properties of icaritin-loaded liposomes based on different surfactants

In this study, development of icaritin-loaded liposomes stabilized by four kinds of surfactants (i.e. Span40, Span20, Sucrose ester and Tween80, with the hydrophile lipophile balance (HLB) numbers of 6, 8, 9 and 16, respectively) was presented, which tackled the poor solubility and low physicochemical stability of icaritin in the aqueous phase. The addition of icaritin and cholesterols into the bilayers exhibited an increase in the average diameter and high encapsulation efficiency, regardless of the variety of surfactants. Meanwhile, when cholesterols were absent, surfactants with low HLB numbers (≤9) produced liposomes with higher average sizes (nearby 200nm) and zeta-potentials (−20 to −35mV) than Tween80. DPPH and ABTS+ free radical-scavenging experiment exhibited different activities due to the diverse profiles of the free radicals, where their polarity and solubility must be taken into account. Physicochemical stability results revealed that Sucrose ester and Tween80 liposomal systems had the best physical and thermal stability, respectively. In addition, UV–vis absorption spectra and FTIR analysis confirmed that the formation of hydrogen bonds promoted the embedding effects of icaritin. Last but not the least, in vitro digestion experiment demonstrated that those liposomes containing Sucrose ester and Tween80 had the highest release levels, up to 75.68±0.25% and 77.23±0.58%, respectively. Therefore, these results suggested that the surfactants selection could be promising strategy for manufacturing different functional liposomal foods with different bioactive substance under various storage conditions.

EFFECT OF HLB NUMBERS OF SURFACTANT ON THE RHEOLOGICAL PROPERTIES OF HMX-BASED ENERGETIC INK

Energetic ink, combined with energetic materials and additives through adaptive three-dimensional printing technology, is a promising method of replacing traditional charge styles, and its rheological property is an important factor in the preparation process. Sorbitan monooleate (Span-80) and polyoxyethylene sorbitan monooleate (Tween-80) are two surfactants that have been commonly used to improve the rheological properties of suspensions. The influence of surfactants in the viscosity of energetic ink is a significant issue that is worth exploring. The effects of the surfactant percentage and hydrophilic−lipophilic balance (HLB) numbers on ink viscosity were obtained based on the the addition of different contents of Span-80 and Tween-80 to an ultrafine cyclotetramethylenete tranitramine (HMX)/alcohol nylon/ethanol system. The results are presented using the rules of viscosity, the non-Newtonian indexes that reflected the rheological stability, and the yield values that reflect the degree of difficulty from the static state to flow. The best HLB number that effectively increased the rheological property in this study was chosen according to the results, which may provide some reference for additives in the preparation process of energetic ink.

Equilibria of cyclopentane hydrates with varying HLB numbers of sorbitan monoesters in water-in-oil emulsions

This study investigated the effect of hydrophilic-lipophilic balance (HLB) numbers of sorbitan monoesters on equilibrium conditions of cyclopentane hydrates in water-in-oil emulsions with or without NaCl. HLB numbers of the surfactants (Span 20, 40, 60, and 80), which have the same hydrophilic group, are determined by the length and shape of alkyl chain and the HLB number refers to hydrophobicity of surfactant. The equilibrium state of the hydrate phase can be affected by the HLB of the surfactants whose number is the lowest in Span 80 (4.3) and the highest in Span 20 (8.6). The emulsion size is proportional to the increasing HLB number of sorbitan monoesters. Equilibrium dissociation temperatures of cyclopentane hydrate in the water-in-oil emulsion also rise as the HLB number increases, which was determined in micro differential scanning calorimetry (micro-DSC). In the presence of 3.5 wt % NaCl in the aqueous phase, hydrate equilibrium temperatures were almost constant regardless of the HLB number because the salt ions diminished the interaction between water and sorbitan esters as a thermodynamic hydrate inhibitor. This HLB-dependent behavior provides basic insights into the relationship between clathrate hydrate equilibria and hydrophobicity in the hydrate-forming emulsion system.

Ultrafine coal dewatering: Relationship between hydrophilic lipophilic balance (HLB) of surfactants and coal rank

Dewatering process is one of the most costly steps in mineral processing and coal washing plants. This fact becomes an important industrial challenge in lignite cleaning. The presence of micropores and relatively low hydrophobic nature of lignitic coal lead to trapping of large quantities of water in the coal matrix especially in fine sizes. Since lignites are used as a common fuel in power stations, they need to be dried to a certain moisture level before feeding to the combustion chamber. Dump feeding in power plants cause inevitable loss of efficiency and may be deleterious for combustion sections. It is thus generally wise to dewater coal as much as possible by physical means before it is dried. However, further dewatering cost in some cases may be prohibitive particularly for fine and hydrophilic particles.In this study, various type and amount of surfactants have been tested to increase the efficiency of coal dewatering. As the hydrophobic characteristic of coals varies and increases with increasing the coal rank, dewatering of bituminous and anthracite type coals can be accomplished using low HLB surfactants (Oily), however, these surfactants are not efficient in the case of low rank coals like lignites and brown coals. A special set-up has been designed to study the effect of high HLB surfactants on dewatering of ultrafine lignite particles. It is shown that, while surfactants with lower HLB number and oily characteristics are the most convenient dewatering reagents for slightly hydrophobic surfaces such as hard coals, surfactants with higher HLB values especially those with HLB of around 10 are the most efficient reagents for dewatering of ultrafine lignite and lower rank coals. The governing mechanisms are discussed in the light of hydrophilicity index and modification of physicochemical conditions.

A proposal to use excess Gibbs energy rather than HLB number as an indicator of the hydrophilic–liphophilic behavior of surfactants

The HLB (hydrophilic–lipophilic balance) number has been widely used in quantifying the behavior of polar molecules in emulsions. It has also been used in attempting to explain the behavior of surfactants in flotation systems. The origin of the HLB concept lies in defining the behavior of molecules in terms of the contributions of various groups in their molecular structure. This paper proposes that modern thermodynamics provides a much more robust method of defining such behavior through the concept of excess Gibbs free energy which in turn is obtained from the activity coefficients of such molecules. It not only presents a more fundamental basis for the calculation but also there exists a vast number of species for which the key parameters are known or are currently being determined through global initiatives.

Formulation, Rheology, and Hypolepidemic Activity of Vegetable Oil-Based Eggless and Low-Fat Food Emulsions

Common edible oils such as almond, safflower, soybean, and mustard oil were formulated in the form of eggless and low-fat oil-in-water emulsions using a blend of nonionic emulsifier Glycerol monostearate and amphoteric emulsifier soy lecithin. The emulsion parameters such as vegetable oil, emulsifier, additive content and hydrophilic-lipophilic balance number of emulsifier were optimized. The storage stability of formulated emulsions was monitored under accelerated storage stability conditions for six months. Rheological characterization of stable emulsion revealed pseudoplastic flow behavior. In vivo hypolepidemic activity of formulated emulsions in rats showed considerable reduction in total cholesterol and triglyceride level after 14 days as compared with the marketed product. The almond oil emulsion is found superior than safflower oil emulsion.

Synthesis and electrochemical characterization of LiFePO 4/C composites prepared by the microemulsion method

Electroactive LiFePO 4/C composite powders were successfully prepared by the microemulsion process under controlled conditions. A series of residual carbons on the surface of prepared LiFePO 4 materials originating from the pyrolysis of various salt concentrations, Hydrophile-Lipophile-Balance (HLB) values, and structures of organic surfactants were characterized. All samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectral analysis, BET surface area, cyclic voltammetry (CV) and charge–discharge tests. The performance of the LiFePO 4/C composite powders displayed a strong relationship between the emulsion conditions and structures of surfactants. Lower salt concentrations of the aqueous cores or a smaller HLB numbers cause the formation of small aqueous cores resulting in smaller particle sizes of LiFePO 4/C composites after calcinating the cores. The molecular structures of surfactant affect the formation of micelle size and further influence the behavior of the LiFePO 4/C composite. The OP-7 surfactant contains more branched structures on the lipophilic groups causing the formation of small aqueous cores and particle sizes of LiFePO 4 after calcination of the cores. Small aqueous cores formed smaller particles with lower I D/ I G values after pyrolysis yielding composites with higher discharge capacities.

Method for determining the best hydrophilic-lipophilic balance (HLB) number for a compatible non-ionic surfactant in formulation development for aerial conidia of Metarhizium anisopliae (Hypocreales: Clavicipitaceae)

A direct dropping method was developed to determine the best hydrophilic-lipophilic balance number of Metarhizium anisopliae conidia at different water content levels during dehydration. Results showed the best HLB number of the tested M. anisopliae conidia was 8; dehydration did not change the best HLB number but significantly increased wetting time.

Application of hydrophilic–lipophilic balance (HLB) number to optimize a compatible non-ionic surfactant for dried aerial conidia of Beauveria bassiana

The hydrophilic–lipophilic balance (HLB) number system was used to optimize a compatible non-ionic surfactant, TDA (polyoxyethylene tridecyl ether) in formulations for two Beauveria bassiana strains, NI8 and GHA. The optimal HLB number for TDA was determined on the basis of wetting times for conidial powders. The results indicated that optimal HLB number of TDA for B. bassiana strain NI8 was 8, while the optimum HLB number for strain GHA was 10. The optimized TDA surfactants required significantly less wetting times than the commonly used laboratory surfactants, Triton X-100, Span 80, and Tween 80. These optimized TDA surfactants were further characterized on their ability to produce conidial suspensions of the two strains after 5 min of mixing, TDA HLB 8 and TDA HLB 10 produced suspensions of 1.8 × 10 8 and 1.6 × 10 8 conidia/ml for NI8 and GHA, respectively. These conidial levels were significantly higher than those in Triton X-100, Span 80, and Tween 80 suspensions after the same mixing time. Germination assays showed that TDA HLB 8 promoted significantly higher germination rates of strain NI8 than those observed in other commonly used laboratory surfactants. However, the germination rates of the GHA strain were unaffected by any of the surfactants tested. The efficacy of the conidial suspensions was confirmed with assays against Lygus lineolaris. Bioassay results indicated that there were no significant differences in mortalities because of surfactants. These results suggest optimization based upon HLB number will not negatively impact parameters associated with efficacy, while providing desirable physical properties.