HLB Value Research Articles

Effect of Surfactant HLB Value on the Dispersion Stability of Carbon Black Paste

Effect of Surfactant HLB Value on the Dispersion Stability of Carbon Black Paste

One-Pot Synthesis of Bimodal Gigaporous Polystyrene Microspheres with Hydrophilic Surfaces

Hydrophilic gigaporous polystyrene (HGPS) microspheres with bimodal pore distributions were first synthesized in one step, using amphiphilic diblock glycopolymers (ADG) and toluene as macroporogen and mesoporogen, respectively. The effects of different HLB values, molecular weights, and concentrations of ADG as well as the addition of mesoporogen on the morphology of microspheres were investigated in detail. The HGPS microspheres were characterized to possess two type of pores, i.e., gigapores (300–7000 nm) and mesopores (4–50 nm). As a consequence, the column packed with HGPS microspheres presented low backpressure, good permeability, and high column efficiency, indicating the existence of flow-through pores in the particle. Compared to native polystyrene microspheres, the nonspecific adsorption of proteins on HGPS microspheres was greatly reduced by 93.2%. The HGPS microspheres can be easily derivatized by classical methods since their surface was hydroxyl-rich glycopolymers. All the results indicate th...

Adsorption of bis(2-hydroxy-3-chloropropyl) dodecylamine on quartz surface and its implication on flotation

Abstract In order to clarify the effect of polar group modification on flotation performance of amine collector, flotation properties of quartz and hematite using bis(2-hydroxy-3-chloropropyl) dodecylamine (N23) as a collector were investigated. And the adsorption mechanism of N23 on quartz surface was established by zeta potential measurements, SEM/EDS measurements, and molecular structure analysis. Single mineral flotation results indicated that N23 showed stronger collecting ability on quartz and hematite than DDA-CH 3 COOH. However, starch could depress the flotation of hematite. Flotation recovery of 98.10% for quartz could be achieved, when N23 concentration was 43.33 mg/L and starch concentration was 16.67 mg/L at natural slurry pH. Separation of artificially mixed minerals of hematite and quartz was achieved effectively using N23 as the collector. The optimized separation result with 66.29% iron grade and 90.06% iron recovery in concentrate was obtained when slurry pH was 7.34 with 43.33 mg/L N23 and 23.33 mg/L starch. The interaction energies of N23 with mineral surface also showed well consistency with flotation results. SEM/EDS analyses and zeta potential measurements revealed that N23 could absorb on quartz surface in the forms of strong electrostatic and hydrogen bonding interaction. Compared with DDA, N23 had a higher HLB value and better water-solubility, which resulted in better dispersion in water and stronger adsorption on mineral surface.

Glyceryl Ether (mono-tert-butoxypropanediol) in Emulsion System

This paper reports the effects of glyceryl ether specifically mono-tert-butoxypropanediol on oil in water emulsion system. Based on 12 HLB value, screening for stable emulsions was carried out without the presence of glyceryl ether. A stable emulsion was used as a control. Then the effects of glyceryl ether on the emulsion system were investigated. The emulsions prepared were analyzed for stability, viscosity, pH value, particle size, in vitro dermal irritation potential, in vitro ocular irritation potential and also moisturizing property. The incorporation of glycerol in the emulsion system was also done for comparison. Emulsions with glyceryl ether showed lower viscosity values than emulsions with glycerol. Furthermore, the emulsions also exhibited moisturizing property compared to the control emulsion. Glyceryl ether is suitable to be used in cosmetic products which require reduced viscosity but retain its skin hydration property.

Destabilization and Separation of Gas Condensate from Wastewater using Different Surfactant Demulsifiers

AbstractAn emulsion of hydrocarbon components in water is usually found in the wastewater of refineries. These emulsions may be broken by adding a suitable demulsifier at the proper concentration with the minimum stability. In this study, different surfactant demulsifiers including hydrophilic and hydrophobic groups with different HLB values (KENON 20, KENON 10, KENON 4, KENON 2, MBG, CTAB, SDS, Span 80, Span 60, PEG, polyamide, polyacrylamide and an EO/PO block copolymer of dodecan-1-ol) were employed for the destabilization and separation of gas condensate droplets in water emulsion. The results revealed that the demulsifiers KENON 2, polyamide, EO/PO block copolymer of dodecan-1-ol and polyacrylamide were effective materials for the destabilization of the emulsion. Additionally, the addition of these demulsifiers leads to growing gas condensate droplets from 5 to about 25 μm showing a very good growth. Moreover, the results showed that the maximum separation of gas condensate from the emulsion were obtained using polyamide and dodecan-1-ol which was approximately 45 vol.% after 2 h at a concentration of 300 ppm of demulsifiers. Furthermore, the maximum gas condensate separation of 70 vol.% was obtained using dodecan-1-ol and KENON 2 after 24 h.

Investigation of oil-in-water emulsion stability with relevant interfacial characteristics simulated by dissipative particle dynamics

Oil-in-water (O/W) emulsions were prepared by using non-ionic surfactants, Tween 80 and Span 20, and the stability of the emulsions was investigated under conditions of varied HLB, emulsifier concentration, stirring time and stirring intensity. It was found that the HLB of emulsifier has a significant effect on the emulsion stability. Moreover, the structures and properties of the interfacial film formed by emulsifier molecules with different HLB were characterized by dissipative particle dynamics (DPD) simulations. The results show that the interfacial film thickness increases with the HLB values changing from 9 to 15, while the most stable emulsion appears when HLB is 13 with the minimum interfacial tension. Neither too small nor too large oil droplet size, determined by molecular volume of emulsifier as well as the volume ratio of hydrophilic head and hydrophobic tail, could improve the emulsion stability when the preparation technology is the same. Therefore, the influence of HLB on the emulsion stability is essentially affected by the comprehensive result of interfacial film thickness, interfacial tension and molecular structure of emulsifier. This study could contribute to the development of controlling and preparation of emulsions with suitable stability from the point of view of emulsifier.

Effect of Surfactant Type, Cholesterol Content and Various Downsizing Methods on the Particle Size of Niosomes.

The present study was conducted to investigate the performance of different size reduction techniques including probe sonication, extrusion, and high pressure homogenization for nanosizing of niosomes. Also, the effects of cholesterol content and surfactant type on the size and poly dispersity index (PDI) of the formulations were evaluated. Various niosomal formulations composed of Brij 72, Span 60, or Tween 60 were prepared and then, to reduce vesicle size and minimize the PDI, the niosomes were treated by various post-processing procedures. Surfactant type showed a significant effect on the particle size of the niosomes. The particle size of Tween 60 niosomes was significantly larger than those of Span 60 and Brij 72 niosomes (P < 0.05), indicating that at the same cholesterol content, niosomes composed of a surfactant with a higher HLB value show larger particle size than those with a lower HLB value. The influences of cholesterol content as well as downsizing methods, on the particle size and distribution of niosomes were significantly dependent on the surfactant composition of the niosomes. Extrusion and probe sonication were found to be the most efficient methods for size reduction of the Tween 60 and Span 60 niosomes, while for downsizing of Brij 72 niosomes, all employed methods were efficient and resulted in the approximately similar size of about 200 nm. In conclusion, the selection of an efficient method for nanosizing of niosomes and also achievement of a desired size range, and homogeneity highly depends on the niosome composition, particularly on the employed surfactant type.

Investigation of Water-in-Biodiesel Emulsion Characteristics Produced by Ultrasonic Homogenizer

Limited studies had been conducted using water-in-diesel emulsion produced from ultrasonic homogenizing method. In this study, Water-in-Biodiesel Emulsions (WiBE) produced using ultrasonic homogenizer were characterized and studied for their physical and chemical properties through various laboratory investigations. The data were then compared with WiBE produced using mechanical homogeniser by the current researchers. Physical characterization tests were carried out on 24 WiBE emulsions produced using an ultrasonic bath, with water percentage of 9%, 12% and 15%, HLB value of 6, 7, 8 and 9, and surfactant dosage of 5% and 10%. The water droplets produced using ultrasonic homogeniser were found to be evenly distributed and generally smaller in size. The density and viscosity values of these emulsions were found to be uniformly larger than WiBE produced using mechanical homogeniser. Emulsions with 15% water exceeded the density threshold, indicating the limits of the amount of water which can be added to the biodiesel fuel. Also, it was found that for viscosity, the HLB is limited to HLB 9 for higher surfactant dosage.

Determination of HLB values of some nonionic surfactants and their mixtures

Determination of HLB values of some nonionic surfactants and their mixtures

Encapsulation and stabilization of β-carotene by amylose inclusion complexes

In the present study, we report a novel composition based on amylose (or starch) inclusion complex with an amphiphilic material as an effective encapsulation platform technology to incorporate guests of interest. Specifically, the encapsulation of β-carotene in amylose-surfactant and amylose/starch-ascorbyl palmitate (AscP) inclusion complexes was investigated. Surfactants of different hydrophilicity/lipophilicity were selected to cover a broad range of HLB values. The formation of the inclusion complexes was characterized by X-ray diffraction and differential scanning calorimetry. The ability of amylose-surfactant system to encapsulate β-carotene was dependent on the HLB value of the surfactants, instead of their ability to induce inclusion complexation. The incorporation of β-carotene hindered amylose-surfactant inclusion complex formation, whereas no significant effect was observed on structural and thermal properties of starch-AscP inclusion complex in the presence of β-carotene. The X-ray diffraction pattern of amylose-AscP-β-carotene showed that β-carotene molecules did not crystallize into a separated phase and thus were suggested to be homogeneously immobilized within the polycrystalline amylose-AscP inclusion complexes. During a storage period of six weeks at 20 and 30°C, the stability of β-carotene was improved by encapsulation in starch-AscP inclusion complexes compared with that in physical mixtures of the three components.

Fully Stable and Homogeneous Lyotropic Liquid Crystal Alignment on Anisotropic Surfaces

Lyotropic chromonic liquid crystals have great potential in both biosensing and optical devices due to their biocompatible nature and strong optical characteristics. These applications, however, demand a homogeneous and stable alignment on anisotropic surfaces, a challenge that, so far, has not been solved adequately. In this work, it is shown how to drastically increase the quality of in‐plane alignment and stability of these liquid crystals on conventional rubbed polyimide substrates by the addition of a small amount of a nonionic surfactant. Samples with surfactant show excellent alignment that is stable for months, while control samples without surfactant show much poorer alignment that further deteriorates in days. Also, well‐aligned dry films of chromonics can be prepared following this approach. It is demonstrated how to obtain high‐quality alignment by controlling the concentration and the nature of the surfactant, in particular its molecular structure and hydrophilic/lipophilic balance (HLB value) and other critical parameters are discussed. It is believed that this approach may very well be essential for advancing the applicability of these water‐based, biocompatible, and often highly dichroic materials for a wide range of uses.

The stability study of CO2 foams at high pressure and high temperature

CO2 foam is effective for mobility control and blocking of high permeability channels in the process of CO2 flooding for enhanced oil recovery. CO2 foams are much less stable than nitrogen foams due to the specific properties of CO2, and selection of surfactants as foaming agents is important for foam performance under harsh reservoir conditions. In this study, different surfactants and their mixtures were tested to evaluate their performance as CO2 foam agents, and the experiments were conducted using a visualized foam meter and a core flooding facility at high pressure and high temperature conditions. The influences of temperature, pressure, salinity and the HLB value of surfactants on CO2 foaming capability were investigated. The synergistic effect of the surfactants was also evaluated in order to increase high temperature tolerance of the foams. The experimental results show that the performance of CO2 foams at high temperature is greatly dependent on the types of the surfactants used. For nonionic and anionic-nonionic surfactants, there is a critical or optimum HLB value for best foam performance. Pressure has a positive effect on the stability of CO2 foams but dependent on the HLB value of the surfactants. Combined or mixed surfactants have a synergistic effect that can significantly improve the performance of CO2 foams and increase the foam's stability at high temperatures.

Incomplete phase inversion W/O/W emulsion and formation mechanism from an interfacial perspective

ABSTRACTWater-in-oil-in-water (W/O/W) double emulsion can be prepared by incomplete phase inversion method using both medium chain triglycerides (MCT) and isopropyl myristate (IPM) as oil phase, Span 85-Tween 80 (HLB values of 2.5-3.0) as mixed emulsifiers. The preparation method was simple, and the final double emulsions were proved of good microstructure and particle size distribution. Owning to the addition of Tween 80 to Span 85, interfacial tension, interfacial viscosity and modulus decreased, which contributed to the phase inversion. Furthermore, formation of reverse micelles under high-speed dispersion may be a hypothesis to explain the incomplete phase inversion phenomenon.

Emulsions Co-Stabilised by Edible Pickering Particles and Surfactants: The Effect of HLB Value

• Comparison of two extreme HLB values surface-active species • Performance of Pickering particles is improved by addition of surfactants. • Formation of mixed-emulsifier systems with enhanced interfacial activity • Synergy between particles and surfactant can lead to smaller droplet size emulsions. • Surfactant's HLB value and concentration are the two most important parameters.

A gemini-type superspreader: Synthesis, spreading behavior and superspreading mechanism

This paper describes the facile microwave-assisted synthesis of a series of trisiloxane gemini superspreaders, as well as their surface and aggregation properties and superspreading behavior on plant leaf surfaces. The molecular structures of the trisiloxane gemini surfactants were characterized by Fourier transform infrared spectroscopy (FTIR) and 1H nuclear magnetic resonance spectroscopy (1H NMR). The obtained thermodynamic parameters showed that an increase in the spacer group (CH2) resulted in decreases in the critical aggregation concentration (CAC), corresponding surface tension (γCAC), and surface excess concentration (Γmax) but increases in the occupied area per surfactant molecule (ACAC) and absolute values of the standard free energies of aggregation (ΔGθmic) and adsorption (ΔGθads). An increase in ethoxy units (CH2-CH2-O-) resulted in increases in the CAC, γCAC, and ACAC but decreases in Гmax and the absolute values of ΔGθmic and ΔGθads. The transmission electron microscopy and dynamic light scattering results showed that the average sizes of the aggregates of superspreader solutions increased with an increasing number of spacer units (CH2) but decreased with an increasing number of ethoxy units (CH2-CH2-O-). The dynamic spreading behavior results demonstrated that the average spreading velocity increased with increasing spacer chain length, and the dependence of the maximum spreading velocity on the ethoxy chain length was nonmonotonous with a maximum at n(EO)=8.68. The optimal HLB value was essential to obtaining good superspreading behavior, and the substrate wettability (hydrophobic rice plant and hydrophilic mango plant surfaces) greatly influenced the superspreading. The synergistic effects from the precursor film and Marangoni effect existed in the proposed superspreading model.

Ocular ketoconazole-loaded proniosomal gels: formulation, ex vivo corneal permeation and in vivo studies

Context: Vesicular drug carriers for ocular delivery have gained a real potential. Proniosomal gels as ocular drug carriers have been proven to be an effective way to improve bioavailability and patient compliance.Objective: Formulation and in vitro/ex vivo/in vivo characterization of ketoconazole (KET)-loaded proniosomal gels for the treatment of ocular keratitis.Materials and methods: The effect of formulation variables; HLB value, type and concentration of non-ionic surfactants (Tweens, Spans, Brijs and Pluronics) with or without lecithin on the entrapment efficiency (EE%), vesicle size and in vitro KET release was evaluated. An ex vivo corneal permeation study to determine the level of KET in the external eye tissue of albino rabbits and an in vivo assessment of the level of KET in the aqueous humors were performed.Results and discussion: In vivo evaluation showed an increase in bioavailability up to 20-folds from the optimum KET proniosomal gel formula in the aqueous humor compared to drug suspension (KET-SP). The selected formulae were composed of spans being hydrophobic suggesting the potential use of a more hydrophobic surfactant as Span during the formulation of formulae. Factors that stabilize the vesicle membrane and increase the entrapment efficiency of KET (namely low HLB, long alkyl chain, high phase transition temperature) slowed down the release profile.Conclusions: Proniosomal gels as drug delivery carriers were proven to be a promising approach to increase corneal contact and permeation as well as retention time in the eye resulting in a sustained action and enhanced bioavailability.

Highly Viscoelastic Reverse Wormlike Micellar Systems from a Mixture of Lecithin, Polyglycerol Fatty Acid Monoesters, and an Oil.

We report new lecithin reverse wormlike micelles with high viscoelasticity formed using lecithin/polyglycerol fatty acid monoester (PGLFA)/oil systems. In this study, the influence of the amphiphilicity (i.e., hydrophile-lipophile balance, HLB) of PGLFA on the phase behavior and rheological properties of reverse wormlike micelles was investigated in detail. PGLFAs with degrees of polymerization of polyglycerol varying between 6-40 and constituent fatty acids with chains between 6-18 carbon atoms long were used. Partial phase diagrams of the lecithin/PGLFA/n-decane systems indicated that the appropriate PGLFA could change the lecithin/oil solution into a highly viscoelastic solution comprising reverse wormlike micelles. Rheological measurements showed that all systems that formed reverse wormlike micelles exhibited an unusual phenomenon called "shear-thickening". Furthermore, reverse wormlike micelles grew as the PGLFA concentration increased and the zero-shear viscosity (η0) of the solution rapidly increased. Our results indicate that the magnitude of the maximum η0 depends on the degree of polymerization of the constituent polyglycerol in the PGLFA, while the size of the reverse micellar region and the highly viscous region in the phase diagram depends on the HLB value of the PGLFA.

Agglomeration of Celecoxib by Quasi Emulsion Solvent Diffusion Method: Effect of Stabilizer.

Purpose: The quasi-emulsion solvent diffusion (QESD) has evolved into an effective technique to manufacture agglomerates of API crystals. Although, the proposed technique showed benefits, such as cost effectiveness, that is considerably sensitive to the choice of a stabilizer, which agonizes from a absence of systemic understanding in this field. In the present study, the combination of different solvents and stabilizers were compared to investigate any connections between the solvents and stabilizers. Methods: Agglomerates of celecoxib were prepared by QESD method using four different stabilizers (Tween 80, HPMC, PVP and SLS) and three different solvents (methyl acetate, ethyl acetate and isopropyl acetate). The solid state of obtained particles was investigated by differential scanning calorimetry (DSC) and Fourier transform infrared (FT-IR) spectroscopy. The agglomerated were also evaluated in term of production yield, distribution of particles and dissolution behavior. Results: The results showed that the effectiveness of stabilizer in terms of particle size and particle size distribution is specific to each solvent candidate. A stabilizer with a lower HLB value is preferred which actually increased its effectiveness with the solvent candidates with higher lipophilicity. HPMC appeared to be the most versatile stabilizer because it showed a better stabilizing effect compared to other stabilizers in all solvents used. Conclusion: This study demonstrated that the efficiency of stabilizers in forming the celecoxib agglomerates by QESD was influenced by the HLB of the stabilizer and lipophilicity of the solvents.

Effects of nonionic surfactants on pellet formation and the production of β-fructofuranosidases from Aspergillus oryzae KB.

Aspergillus oryzae KB produces two β-fructofuranosidases (F1 and F2). F1 has high transferring activity and produces fructooligosaccharides from sucrose. Mycelial growth pellets were altered by the addition of Tween 20, 40 and 80 (HLB=16.7, 15.6 and 15.0, respectively) in liquid medium cultures to form small spherical pellets. The particle size of the pellets decreased with the HLB value, which corresponds to an increase in surfactant hydrophobicity. Selective F1 production and pellet size were maximized using Tween 20. Adding polyoxyethylene oleyl ethers (POEs) with various degrees of polymerization (2, 7, 10, 20 and 50: HLB=7.7, 10.7, 14.7, 17.2 and 18.2, respectively) was investigated. A minimum mean particle size was obtained using a POE with DP=10, HLB=14.7. The POE surfactants had little effect on the selective production of F1. The formation of filamentous pellets depended on the surfactant HLB value, and F1 enzymes were produced most efficiently using Tween 20.

Highly stable graphite nanoparticle-dispersed phase change emulsions with little supercooling and high thermal conductivity for cold energy storage

Graphite nanoparticles used as a nucleating agent have been dispersed into a phase change emulsion containing 30wt% of OP10E, aiming at eliminating its supercooling and improving its thermal conductivity. Based on the optimizations using surface response methodology, the stable OP10E emulsion with small droplets can be prepared with the aid of the emulsifier with a HLB value of 8.9 at a loading of 5wt%. It is found that the degree of supercooling for the emulsion decreases from 9.9°C to almost 0°C after the dispersion of the graphite nanoparticles at an optimal concentration of 2wt%, suggesting a complete elimination in supercooling. The addition of the graphite nanoparticles has no effect on latent heat of the OP10E/water emulsion. The thermal conductivity of the emulsion containing 2wt% graphite is 0.578Wm−1K−1, achieving an enhancement by 88.9% as compared to the one without graphite. The viscosity of the emulsion containing 2wt% graphite is lower than 11.5mPas, meeting the transportability requirements for pumping in practical applications. No distinct changes in these properties have been observed for the emulsion after being stored for 30days or being experienced 300 heating-cooling cycles test, implying its good dispersion stability and thermal reliability. The high energy storage capacity, little supercooling, enhanced thermal conductivity, excellent thermal reliability and good fluidity make the graphite nanoparticles-dispersed OP10E/water emulsion show great potential for use as a novel cool storage fluid for high efficiency cool storage device.