Cocoamidopropyl Betaine Research Articles

Emulsification in nearly Newtonian and non-Newtonian media of wormlike micelles

Emulsification experiments with four silicone oils, having viscosities ranging from 0.01 to 30 Pa.s, were conducted in two types of media: nearly Newtonian polyvinyl alcohol (PVA) solutions and non-Newtonian mixtures induced by worm-like micelles in solutions of sodium laureth sulfate and cocoamidopropyl betaine (BS) with NaCl. The increased viscosity of BS solutions upon the addition of NaCl did not significantly affect the drop size in the formed emulsions. In contrast, the increased viscosity of solutions with higher PVA concentrations significantly reduced the drop sizes for all silicone oils. A theoretical expression predicting the maximum drop size in both types of media (nearly Newtonian and non-Newtonian) was derived and validated against experimental data. The expression accounts for shear-thinning behavior in both the aqueous and oil phases. Interfacial stress dominates the breakage of less viscous oils, while viscous stress inside the breaking drop plays a leading role for more viscous oils. The formation of emulsions with similar sizes in non-Newtonian solutions of BS with different NaCl concentrations was explained by their strongly shear-thinning behavior, which leads to nearly similar viscosity at high shear rates, despite their zero-shear viscosities differing by more than two orders of magnitude.

DEVELOPMENT OF AN EXFOLIATING DERMOCOSMETIC FORMULATION WITH BABASSU FIBERS TO HELP ON THE TREATMENT OF ANDROGENETIC ALOPECIA

Androgenetic alopecia is a condition characterized by hair loss associated with exposure to androgens, occurring in genetically predisposed individuals. It causes terminal hair to be replaced by vellus hair, miniaturizing the hair shaft and decreasing hair density. The removal of the stratum corneum of skin due to mechanical exfoliation facilitates the penetration of active ingredients into the scalp by stimulating blood circulation, which can help hair growth. Society's consumption patterns are constantly changing, being the search for sustainability and ESG (Environment, Social and Governance) trends a very popular topic. The aim of this study was to develop an exfoliating dermocosmetic formulation with babassu fibers to help on the treatment of androgenetic alopecia, using the part of the babassu coconut that was originally discarded by the industry. An oil-in-water emulsion was developed with the surfactants lauryl glucoside and cocoamidopropyl betaine, and the emulsifiers cetostearyl alcohol and glyceryl monostearate. The formulation was then analyzed for organoleptic parameters (color, smell and appearance), density, pH and centrifugation. The formulation showed instability in the presence of direct sunlight and heat, indicating possible impasses for its commercialization, since storage in the bathroom may trigger instability. In this way, it can be assumed that storing the product in a refrigerator or even at room temperature (<25°C) will maintain its stability. Based on the results, future studies are needed to assess the stability of the scrub, and the optimization of the formulation will make it possible to obtain an innovative product.

Effect of the mixed micelles of zwitterionic-anionic surfactant on efficiency of antibiotic azithromycin dihydrate

The study highlights the importance of mixed micelles in enhancing the binding and solubilization properties of partially water-soluble medications, using zwitterionic cocoamidopropyl betaine (CAPB) and anionic sodium tetradecyl sulfate surfactants. Surface tension and fluorescence spectroscopy evaluated the critical micelle concentration (CMC) of CAPB-STS mixed micelle. The thermodynamic parameters were assessed using Clint, Rubingh, and Motomura’s approach, which showed a synergistic interaction between the CAPB and STS. UV spectroscopy technique was used to evaluate the applicability of mixed micelle to enhance the solubility and binding constant (Kb) of antibiotic azithromycin dihydrate (AZI). Kb values of AZI were increased from 2.301 to 3.415 and molar solubilization ratio (MSR) values of AZI were increased from 0.228 to 0.801 by decreasing αCAPB from 0.9 to 0.1. The result indicated that zwitterionic CAPB was an electrostatic interaction consisting of both attractive (−CH2COO¯ group) and repulsive (−N+ group) interactions with AZI (−NH+ group), causing AZI molecules to reside in the Stern layer. While STS consisted of a negative −SO4¯ head group, it caused increased electrostatic interaction, and AZI penetrated the palisade layer of mixed micelles. At 7.00 mmolL-1 concentration of αCAPB 0.1, the solubility of AZI in water was increased to 2.77 mmol/L from 0.0032 mmol/L. Additionally, after 8 h, the controlled release of AZI in PBS at pH 7.4 was 95.58 % and decreased up to 30.77 % at αCAPB 0.1 mixed micelles. The observation of controlled AZI release from αCAPB 0.9 to 0.1 indicates that AZI molecules were strongly bound to mixed micelles by both hydrophobic and electrostatic interactions. In the end, a mixed micelle of CAPB-STS could serve as a useful drug-solubilizing agent in pharmaceutical applications.

Molecular insight into the enhanced oil recovery potential of a seawater-based zwitterionic/anionic surfactant compound for heavy oil reservoirs

Zwitterionic/anionic surfactant mixtures can produce many synergistic effects that benefit heavy oil production. In this work, a seawater-based zwitterionic/anionic surfactant compound was prepared using cocoamidopropyl betaine (CAB) and alkyl polyoxyethylene ether sodium sulfate (AES), emphasizing their synergistic effects in enhancing conventional heavy oil recovery. First, the emulsification capability and the oil displacement efficiency of the surfactant compound were tested through laboratory experiments. Then the impacts of salinity, cation types, surfactant formulation and solution pH on surfactant-surfactant or surfactant-heavy oil interactions were systematically explored through molecular dynamics simulations to unveil the underlying mechanisms of enhanced oil recovery. The results showed that, (1) in a seawater-based system, when the AES/CAB concentration ratio was 1:1, a large wormlike micelle was formed due to the cation bridging of Ca2+ and Mg2+ ions, which not only strengthened the attractive interactions between the AES-SO4− and the CAB-N+ functional groups, but also screened the repulsive interactions between the AES-SO4− and the CAB-COO− functional groups. (2) Through mixed adsorption, the arrangement of AES/CAB molecules at the aqueous/heavy oil interface was more compact. (3) By incorporating the AES/CAB mixture into the associative structures of asphaltene and resins, it could effectively weaken the attraction interactions between the asphaltenes and the resins. Through these synergies, an additional oil recovery of 24.93 % was yielded by combining AES/CAB flooding and subsequent seawater flooding, compared to 19.38 % in the pure AES case. This study provides important insights into the microscopic mechanisms of zwitterionic/anionic surfactant mixtures, which can facilitate the effective development of heavy oil reservoirs and guide the complex formulation of cost-effective surfactant compounds.

Self-assembly mechanism and application performance in aqueous solutions mediated by ethylene oxide chains in alcohol ether carboxylates and cocamidopropyl betaine

Zwitterionic Cocoamidopropyl Betaine (CAB) and anionic alcohol ether carboxylates have garnered significant attention within the realms of green and colloid chemistry owing to their inherent biocompatibility, multi-responsiveness, and diverse applications. Systematic inquiry into the physicochemical properties, self-assembly mechanisms, and application efficacy of complex systems comprising alcohol ether carboxylate salts with varying ethylene oxide (EO) units (AECnH, n = 5, 7, 9) and CAB-35 in aqueous solutions was undertaken. It was discerned that the optimum physicochemical attributes of the complex system are attained at a molar ratio of AEC of 0.5 (αAEC = 0.5). Incremental augmentation in the number of EO units facilitated the formation of rod-like micelles, exhibiting relatively unstable characteristics, while a reduction in the number of EO units led to the generation of comparatively stable spherical micelles. The self-assembly of micelles in these hybrid systems predominantly hinges upon hydrogen bonding, electrostatic interactions, and hydrophobic forces. Furthermore, kinetic analysis validated that the genesis of micelles in all three hybrid systems is propelled by enthalpy, with the adsorption process entailing a mechanism characterized by mixed diffusion-kinetic adsorption. The optimal wetting performance of the complex system was observed at αAEC = 0.5, while the foam performance demonstrated a diminishing trend with escalating αAEC. This comprehensive discourse delineates the synergistic mechanisms and application efficacy of two distinct classes of green surfactants with disparate charges in aqueous solutions, while contemplating the influence of varying numbers of ethylene oxide chains. Not only does it furnish fundamental insights into their properties, but it also proffers a novel standpoint for the exploration of green surfactants.

Adsorption of single and mixed surfactants consisting of cocoamidopropyl betaine (CAPB) and sodium dodecyl benzene sulfonate (SDBS) onto zinc surface

Abstract Aqueous solutions of surfactants exhibit remarkable differences in their adsorption properties on metal surfaces. This study evaluates the adsorption of surfactant mixtures on zinc metal surfaces. The adsorption of single surfactants cocamidopropyl betaine (CAPB) and sodium dodecyl benzenesulfonate (SDBS) and their mixtures from aqueous solution at mole fractions of 0.00, 0.25, 0.50, 0.75 and 1.00 on zinc powder at 25 °C was studied. The surface tension of the single and CAPB/SDBS surfactant mixtures was measured in the presence and absence of 2 % zinc powder to determine the adsorption isotherms. The depletion method was employed to carry out the adsorption investigation. The amount of the surfactant adsorbed was also calculated from the shaded area between the surface tension versus concentration curves of these surfactants in the presence and absence of 2 % zinc powder. The highest adsorbed amounts were found to increase with the SDBS content. Furthermore, scanning electron microscope (SEM) images of zinc sheets in solutions containing single or mixed CAPB/SDBS surfactants were taken in the presence and absence of 0.05 M HCl. The micrographs indicated that the CAPB-SDBS surfactant layers formed by precipitation can protect zinc metal from acid corrosion.

Physicochemical Effect on Coal Pores of Hydrocarbon Chain Length and Mixing of Viscoelastic Surfactants in Clean Fracturing Fluids.

Clean fracturing fluids are environmentally friendly and could have broad applications in permeability enhancement of coal seams. The hydrophobic chain length of the viscoelastic surfactant (VES) and the mixing of VESs with different ionic types have marked effects on the performance of clean fracturing fluids. This paper analyzes the effects of the hydrocarbon chain length of VES and mixing of VESs with different ion types on the pores of coal and discusses the mechanisms controlling the pore changes from a physical and chemical perspective. We found that the coal samples treated with clean fracturing fluid B had the largest porosity change. Adding two methylene groups to the hydrocarbon chain of the cationic VES will increase clay swelling in coal treated with fracturing fluids. Adding 0.1 wt % cocoamidopropyl betaine (zwitterionic VES) to cationic VES fracturing fluids can reduce the extent of clay expansion induced by fracturing fluids. VES with a long hydrocarbon chain has a strong ability to remove kaolinite in hard coal, and the addition of zwitterion VES increases the ability of a clean fracturing fluid to remove kaolinite. These results provide theoretical guidance for the synthesis of new VES molecules and the design of new fracturing fluid formulations.

A novel strategy to prepare rubber/clay nanocomposites via compounding clay gel into cocoamidopropyl betaine modified styrene butadiene rubber

In this study, high performance styrene-butadiene rubber (SBR)/clay nanocomposites (NCs) modified by cocoamidopropyl betaine (CAPB) are prepared via an efficient and facile strategy. CAPB-modified SBR was compounded with clay gel via gel compounding method to obtain SBR/clay composites. The effect of processing condition and CAPB on the mechanical properties of the SBR/clay composites was investigated. XRD and TEM results show that clay dispersion in SBR matrix is significantly improved due to the success of CAPB in the hydrophilic modification of SBR. The clay-SBR interaction is enhanced and more SBR molecular chains are adsorbed to the clay, significantly improving the mechanical properties of SBR/CAPB/clay NCs, as demonstrated by SEM and DMA. The maximum tensile strength of SBR/CAPB/clay NCs achieved 16.3 MPa at a clay loading of 40 phr, which is 10 times that of pure SBR. The tensile strength of the SBR/CAPB/clay NC incorporated with 20 phr clay has exceeded that of the SBR composite incorporated with 40 phr commercial organic clay. This work demonstrates that this strategy, which combines the CAPB-modification of SBR with the gel compounding method, is an effective and feasible method to improve the mechanical strength of SBR.

Simulating micelle self-assembly to assess potential for viscosity build in surfactant formulations

Self-assembly of surfactants into complex structures is key to the performance of many formulated products, which form a significant fraction of the world’s manufactured goods. Here we adopt the dissipative particle dynamics simulation approach to explore the self-assembly process of surfactants, with the aim of understanding what information can be obtained that may correlate with an increased zero-shear viscosity of surfactant based products. To this end we experimentally measured the zero-shear viscosity of mixed micelle systems comprised of cocoamidopropyl betaine (CAPB) and sodium lauryl sarcosinate (SLSar), as a function of the CAPB/SLSar mass ratio and pH, and characterised the early stages of self-assembly of the same systems computationally. From simulation we identify three distinct behaviors in the micellar self-assembly process (logarithmic, linear and cubic growth) which we find show some degree of correlation with the experimental zero-shear viscosity. Owing to the relatively short simulation times required, this may provide formulation scientists with a practical route to identify regions of interest (i. e. those with a desired zero-shear viscosity) prior to synthesising de novo (potentially natural) surfactants.

Influence of Surfactant Structure on Polydisperse Formulations of Alkyl Ether Sulfates and Alkyl Amidopropyl Betaines.

Surfactants provide detergency, foaming, and texture in personal care formulations, yet the micellization of typical industrial primary and cosurfactants is not well understood, particularly in light of the polydisperse nature of commercial surfactants. Synergistic interactions are hypothesized to drive the formation of elongated wormlike self-assemblies in these mixed surfactant systems. Small-angle neutron scattering, rheology, and pendant drop tensiometry are used to examine surface adsorption, viscoelasticity, and self-assembly structure for wormlike micellar formulations comprising cocoamidopropyl betaine, and its two major components laurylamidopropyl betaine and oleylamidopropyl betaine, with sodium alkyl ethoxy sulfates. The tail length of sodium alkyl ethoxy sulfates was related to their ability to form wormlike micelles in electrolyte solutions, indicating that a tail length greater than 10 carbons is required to form wormlike micelles in NaCl solutions, with the decyl homologue unable to form elongated micelles and maintaining a low viscosity even at 20 wt % surfactant loading with 4 wt % NaCl present. For these systems, the incorporation of a disperse ethoxylate linker does not enable shorter chain surfactants to elongate into wormlike micelles for single-component systems; however, it could increase the interactions between surfactants in mixed surfactant systems. For synergy in surfactant mixing, the nonideal regular solution theory is used to study the sulfate/betaine mixtures. Tail mismatch appears to drive lower critical micelle concentrations, although tail matching improves synergy with larger relative reductions in critical micelle concentrations and greater micelle elongation, as seen by both tensiometric and scattering measurements.

Phycoremediation potential and agar yield of red macroalgae (Gracilaria corticata) against HEDP (hydroxyethylidene diphosphonic acid) and CAPB (cocoamidopropyl betaine) detergents and the heavy metal pollutants.

The discharge of raw industrial, agricultural, and domestic wastes leads to an increase in heavy metal (HM) burden and detergents in aquatic environs, which can have destructive effects on aquatic organisms. Agarophyte Gracilaria corticata, a major component of seaweed flora of the southern coast of Iran (Bushehr) that contains agar and red pigments, is one of the economically valuable red marine algae. Agar is one of the important polysaccharides with high economic value, widely used in pharmaceutical, medicinal, and cosmetic product manufacturing industries. The aim of this work was to investigate the effect of 5 HMs and two common surfactants in household and industrial detergents on the agar yield, appearance color, and the red algae's phycoremediation potential against HMs. The metal ions were Zn(II), Cu(II), Ni(II), Mn(II), and Cr(VI), and the surfactants were HEDP and CAPB. The analysis results of samples cultured for 60 days in seawater and polluted environments showed that G. corticata can accumulate copper and nickel. In the presence of detergents without HMs, the amount of extracted agar significantly increased compared to the control sample with no change in algae color. But with increasing concentration of HMs, the amount of agar in seaweed samples decreased significantly, and the algae discolored from red to dark green or yellowish-green color (signs of death in the algae). These results show that increasing of HM pollution and detergents can lead to toxicological effects and reduce the species diversity of red seaweeds in the future.

Ultra-Low-Density Drilling Fluids for Low-Pressure Coefficient Formations: Synergistic Effects of Surfactants and Hollow Glass Microspheres

With the increase in drilling fluid density requirements in low-pressure coefficient formations, traditional hollow bead drilling fluids and foam drilling fluids each have different degrees of deficiencies. Through extensive indoor experiments, an amphoteric surfactant (cocoamidopropyl betaine) with better foaming performance was selected to formulate an ultra-low-density drilling fluid that combines a foaming agent and hollow glass microbeads to reduce the density of the fluid, with the following specific formulation: 3% bentonite slurry + 0.3% xanthan gum + 0.5% carboxymethyl cellulose + 0.5% starch + 2% lignite resin + 2% blocking agent + 4% hollow glass microspheres + 0.5% foaming agent + 2% nano blocking agent. The performance of the system was evaluated, and the results showed that: the density of the ultra-low-density drilling fluid did not change much before and after aging at 80 °C and was relatively stable; the filter loss amount of the drilling fluid (tested by API) reached 4.6 mL, which meets the requirements for filter loss of drilling fluid; it can bear the pressure of 12 MPa under a 60–90-mesh sand bed and has better pressure sealing capability than hollow glass microbead drilling fluid.

Effect of Phenoxyethanol and Sodium benzoate on the liquid crystal phase behavior of mixed surfactant system

Surfactants in a mixed concentrated (∼30 wt% and higher)-surfactant system self-assemble to form a variety of liquid crystal (lc) types depending the lc curvature determined by the surfactant chemistries and their relative compositions. Preservatives, fragrances and other minor additives present in an industrial formulation can either incorporate into the lc and/or influence the aqueous phase ionic strength to alter the spatial arrangements of the surfactants and the lc curvature. These mechanisms could additively or competitively determine the lc curvature and thereby the lc types formed. We report on the mechanisms for preservatives Phenoxyethanol (PE) and Sodium benzoate (NaB) governing the lc phase behavior for a mixed concentrated-surfactant system: 16 wt% zwitterionic Cocoamidopropyl betaine (CAPB), and 7 wt% each of anionic Sodium Lauroyl isethionate (SLI), Sodium Methyl Lauroyl Taurate (SMLT), and 6 wt% Lauric acid. The lc type(s), the lc dimensions including inter-lc distances were derived from SAXS and polarized microscopy images. The predominant lc phase without preservatives was H1lc, while anionic SLI and SLMT present in excess were insoluble to form dispersed crystals. The addition of PE molecules resulted in their incorporation in the lc surfactant film to cause a transition to micelles, and Lα lc due to incorporation-induced flattening of the film. NaB molecules prevented micelles formation and preserved the H1lc by serving as a hydrotropic agent. The NOESY spectra for the lc systems with PE or NaB at 0–3 wt% confirmed incorporation of PE in surfactant film as opposed to NaB. For both PE and NaB present in a lc system, the dominance of hydrotropic nature of NaB causing film bending rather than the film flattening effect of PE at low (∼1 wt%) PE levels resulted in H1lc as the predominant phase, and reduced dominance of film bending effect at a high PE level (≥ 2 wt%) led to the formation of Lα lc.

Synthesis, surface activity and performance in “green” shampoo formulations of new carboxybetaine‐type surfactants

AbstractNovel zwitterionic surfactants—(N‐methylalkylamide‐derived) [3‐(alkylmethylamino)‐3‐oxopropyl] dimethylammonium acetates (abbr. CnDMPAB, n = 10, 12, 14, and 16) have been rationally designed as multifunctional surface active compounds with the intended characteristics toward their application in natural shampoo formulations. The synthetic routes included the alkylation of N‐methyl‐N‐alkylamines with methyl 3‐(dimethylamino)propionate, followed by betainization, while the purification steps enabled the isolation of high‐purity products for physicochemical analyses. Surface activity and micellization properties of novel CnDMPAB surfactants were studied by surface tension isotherms, and their wettability by advancing and receding contact angle measurements utilizing the Wilhelmy method. The aim of these studies was to exhibit the full potential of CnDMPAB series compounds as the multifunctional components of modern, salt‐free shampoo formulations with confirmed natural origin. The performance activity studies of shampoos, containing CnDMPAB surfactants, as well as model formulation (with commercial cocoamidopropyl betaine), included organoleptic and foaming characteristics, viscosity measurements, dispersibility in distilled and tap water as well as microbiological characteristics. Our studies showed great potential of novel CnDMPAB surfactants in replacing commercial cocoamidopropyl betaine, especially considering their increased viscosity, faster dispersibility as well as enhanced natural origin content.

Effect of cocoamidopropyl betaine on CH4 hydrate formation and agglomeration in waxy oil-water systems

Hydrates and waxes are the two major factors that provoke flow assurance issues in deep-water multi-phase transport units in the energy industry, and the application of eco-friendly and efficient anti-agglomerants is one of the key strategies for addressing this problem. The present work investigates the anti-aggregation performance of an environment-friendly amphoteric surfactant, Cocamidopropyl betaine (CAPB), in wax-containing oil-water systems. It is found that the anti-aggregation performance of CAPB in wax-containing oil-water systems is synergistically influenced by the concentration of CAPB and the wax content. The addition of 1.5 wt% CAPB can effectively inhibit hydrate formation and improve the flow of hydrate slurry in oil-water systems without wax. The addition of 2.0 wt% CAPB slows the growth rate of hydrates and reduces inter-particle aggregation in waxy oil-water systems containing 2.5 wt% n-Pentadecane. The wax content does not affect the amount of hydrate formation but influences the induction time and growth rate of hydrate formation. Additionally, the microscopic analysis further reveals that the addition of surfactant CAPB does not affect the crystal structure of hydrate, but has a significant influence on the distribution of methane molecules in the crystal cavities, particularly in wax-containing oil-water systems.

Coagulation/flocculation-flotation harvest of Microcystis aeruginosa by cationic hydroxyethyl cellulose and Agrobacterium mucopolysaccharides

Efficient biocoagulants/bioflocculants are desired for removal of Microcystis aeruginosa, the dominant harmful bloom-forming cyanobacterium. Herein, we reported cationic hydroxyethyl cellulose (CHEC) inactivated M. aeruginosa cells after forming coagulates and floating-flocculated them with aid of Agrobacterium mucopolysaccharides (AMP) and surfactant. CHEC exhibited cyanocidal activity at 20mg/L, coagulating 85% of M. aeruginosa biomass within 9h and decreasing 41% of chlorophyll a after 72h. AMP acted as an adhesive flocculation aid that accelerated and strengthened the formation of flocs, approaching a maximum in 10min. Flocs of M. aeruginosa were floated after foaming with cocoamidopropyl betaine (CAB), which facilitated the subsequent filter harvest. 82% of M. aeruginosa biomass was suspended on water surface after treated with the coagulation/flocculation-flotation (CFF) agents containing CHEC (25mg/L), AMP (177mg/L) and CAB (0.1mg/L). All components in CFF agents at the applied concentrations did not inhibit acetylcholinesterase or Vibrio fischeri. Our findings provide new insights in developing bio-based materials for sustainable control of cyanobacterial blooms.

Insight into the microplastics release from disposable face mask: Simulated environment and removal strategy

The fight against the COVID-19 epidemic significantly raises the global demand for personal protective equipment, especially disposable face masks (DFMs). The discarded DFMs may become a potential source of microplastics (MPs), which has attracted much attention. In this work, we identified the detailed source of MPs released from DFMs with laser direct infrared spectroscopy. Polypropylene (PP) and polyurethane (PU) accounted for 24.5% and 57.1% of released MPs, respectively. The melt-blown fabric was a dominant MPs source, however, previous studies underestimated the contribution of mask rope. The captured polyethylene terephthalate (PET), polyamide (PA), polyethylene (PE), and polystyrene (PS) in airborne only shared 18.4% of released MPs. To deepen the understanding of MPs release from medical mask into the aquatic environment, we investigated the effects of environmental factors on MPs release. Based on regression analysis, the effects of temperature, incubation time, and wearing time significantly affect the release of MPs. Besides, acidity, alkalinity, sodium chloride, and humic acid also contributed to the MPs release through corroding, swelling, or repulsion of fibers. Based on the exposure of medical mask to simulated environments, the number of released MPs followed the order: seawater > simulated gut-fluid > freshwater > pure water. Considering the risk of MPs released from DFMs to the environment, we innovatively established a novel flotation removal system combined with cocoamidopropyl betaine, achieving 86% removal efficiency of MPs in water. This work shed the light on the MPs release from DFMs and proposed a removal strategy for the control of MPs pollution.

Cosurfactants for controlling the surface properties of diluted solutions: Interplay with bulk rheology of concentrated solutions

The effect of the fatty alcohols (CnOH), fatty acids (CnAc), alkyltrimethyl ammonium bromides (CnTAB), alkyl sulfates (CnSO4Na) and alkyl acetates (CnAcet), with n varied between 6 and 12 C-atoms, on the surface properties of 0.5 wt% mixed solutions of sodium laurylether sulfate (SLES) and cocoamidopropyl betaine (CAPB) was studied. It was shown that the equilibrium surface tension decreases with increasing the cosurfactant chain-length. For example, the addition of C12OH to SLES+CAPB solution decreases its surface tension from 29 down to 22 mN/m. Both the dynamic surface tension and the characteristic adsorption time pass through a deep minimum when cationic or nonionic cosurfactants with 8 or 10 C-atoms are added. The minimum is particularly deep for nonionic surfactants with small head group (acids and alcohols) which destabilize the micelles and increase the rate of surfactant adsorption. The addition of anionic cosurfactants does not change the dynamic and equilibrium surface tensions of SLES+CAPB system. A strong correlation between the dynamic surface tension of diluted surfactant solutions (0.5 wt%) and the viscosity of the respective concentrated solutions (10 wt%) is established and explained for nonionic cosurfactants.

Strategies for the evaluation of the eye irritation potential of different types of surfactants and silicones used in cosmetic products

The ocular irritation potential of products that may come into contact with the eyes should be assessed by the combination of different in vitro alternative methods to determine different mechanisms of toxicity previously evaluated by the Draize in vivo assay. Thus, this study proposed to apply two strategies for the prediction of the eye irritation potential of different concentrations of surfactants and silicones, the first one involving evaluation Hen's Egg Test – Chorioallantoic Membrane (HET-CAM), and the other one using Bovine Corneal Opacity and Permeability (BCOP) followed by histopathological. HET-CAM was considered important in assessing the ocular irritation potential and, despite classifying almost all surfactants as “severe irritants”, it could discriminate moderate and slight irritant SLES concentrations as well as Cocoamidopropyl Betaine as a severe irritant, when the coagulation score was taken into consideration. The BCOP assay alone also did not offer a good prediction of the irritant potential of surfactants, since almost all of them were classified as “no prediction can be made”. However, the histopathological evaluation of the BCOP corneas was very important for establishing the degree and depth of damage related to reversibility. The present study also showed those strategies are sensitive to small variations in the studied anionic, cationic amphoteric surfactant concentrations and can be used for predicting their toxicity in the final product and can be used depending on the focus of the analysis.

Effects of surfactants on activity and structure of egg yolk antibody

Egg yolk antibody (IgY) is a superior functional antibody, which can be widely utilized in food, medical diagnosis, and daily chemical industry. Specific anti-Streptococcus mutans IgY can effectively prevent the occurrence of caries. It has the great potential to be used in active toothpaste against caries. However, the effect of surfactants used in toothpaste on the activity and structure of IgY should be evaluated. As ELISA methods revealed, sodium dodecyl sulfate (SDS) generated a great loss of IgY activity compared to the impacts of cocoamidopropyl betaine (CAB). The thermal transition temperature of the CAB-IgY mixture was extended backwards, while SDS-IgY had basically no apparent endothermic peak illustrating the protein was denatured prior to heating. The conformation and secondary structure changes of IgY can also be observed from the blue shift of aromatic amino acid, fluorescence quench, and FTIR spectrum at presence of SDS. By contrast, CAB behaved no significant destruction on IgY and could be used as a great foaming agent in the antibody toothpaste.