Sodium Dodecyl Benzene Sulfate Research Articles

Study the Effect of Phenol on formation of Supramolecular gel

In this work, the cationic surfactant hexacetyl pridinium chloride (HCPC) was blended with anionic surfactant Sodium Dodecyl benzene Sulfate (SDBS) by using different concentrations (0.0025 - 0.1M) of phenol and at temperature ranges (20-35 Co). It was found that the viscosity values for the mixture of SDBS / HCPC at a certain mixing ratios (12/3, 10.5/4.5 and 9/6), were increased in the presence of phenol, due to formation of self-assembled supramolecular. Moreover, the thermodynamic functions as well as the activation energy for the process of self-assembled were calculated. Conductivity measurements were also performed for further support. The results revealed a physical interaction insight intermolecular forces.

Total oxidisable precursor assay towards selective detection of PFAS in AFFF

Total oxidisable precursor assay (TOP assay) can degrade and convert “unknown” per- and polyfluoroalkyl substances (PFAS) to detectable PFAS. However, the detailed degradation pathway is still not known, particularly when the TOP assay is applied to analyse complex samples such as aqueous film-forming foam (AFFF). To gain insights into the pathway and the effectiveness of the TOP assay, several “known” compounds are first tested as controls, including sodium dodecyl benzene sulphate (SDBS), perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS). Secondly, the test is expanded to several PFAS precursors such as 6:2 fluorotelomer sulfonate (6:2 FTS), 8:2 fluorotelomer sulfonate (8:2 FTS), and a cationic surfactant N-ethyl-N-(2-hydroxyethyl) perfluorooctyl sulfonamide (EtFOSE). Thirdly, the TOP assay is used to test “unknown” PFAS samples that have been previously used as AFFF in Australia. The degradation products are monitored, to compare the mass balance and propose the degradation pathway. While HPLC-MS/MS is typically employed to detect the individual TOP assay products, most of which are perfluoroalkyl carboxylic acids (PFCA), an app-based smartphone sensor can also provide semi-quantitative results as a sum. Overall, the results indicate the effectiveness of the TOP assay to assess the presence of PFAS precursors in the AFFF samples, with some variations in the end products. Recommendations for enhancement of the TOP assay are also provided.

Near-infrared spectroscopy and machine learning-based classification and calibration methods in detection and measurement of anionic surfactant in milk

The monitoring of milk and milk-based products are crucial in the dairy industry because of their global consumption, fraudulent practice applied to mask the quality parameters for gaining more profit. Non-destructive near-infrared (NIR) spectroscopy and machine learning (ML) methods like interval partial least squares (iPLS), principal components analysis (PCA), and soft independent modeling of class analogy (SIMCA) were used to classify and discriminate pure milk samples from adulterated with an anionic surfactant. The surfactant’s model was sodium dodecylbenzene sulfate (SDBS) in different concentrations (1.94–19.4 gkg−1). ML models were assessed by sensitivity, specificity and efficiency rates as classification figures of merit. As a result, iPLS regression method based on standard normal variate (SNV) pre-processed spectra provided better performance compared to partial least squares (PLS) regression with a full-spectrum dataset. The root mean square error of cross-validation (RMSECV) was 0.123 and 0.135 for the iPLS and full-spectrum models, respectively. PCA as a qualitative grouping analysis demonstrated separate clusters of samples in terms of their concentration level of SDBS. For the iPLS dataset in SIMCA model, all classification figures of merit were recorded 100 % for pure milk samples. In contrast, the average sensitivity, specificity and efficiency rates were 97.6 %, 93 %, and 94.9 % for adulterated samples.

Heat transfer study on flowing liquid film of SiO2‐water nanofluid with surfactant confined by metallic foam

SummaryTo solve the urgent issue of rapid heat dissipation in narrow spaces of electronic devices, the nanofluid as coolant is an effective way, in the cases that the thermo‐physical properties and stabilities of coolant solution can be improved by the dispersion of nanoparticles and surfactant in the base fluid, and scattering sodium dodecyl benzene sulphate (SDBS) as the surfactant and SiO2 nanoparticles, respectively, at different concentration ratios into the base fluid of water to form SiO2‐SDBS‐water (SSW) nanofluid in current research. In the liquid film of SSW nanofluid flowing across heating surface confined by porous metal foam, the effects of the concentration ratios of nanoparticles and surfactant on heat transfer and mechanism of heat transfer enhancement are analyzed in gradual heating and rapid cooling. The boiling and cooling performances can be improved in the SSW nanofluids with the proper concentrations of SiO2 nanoparticles as well as matching surfactant, and the deterioration in heat transfer occurs with the mentioned concentrations exceeding the critical values. In the cooling process, the variation of critical heat flux happens with the concentrations of SiO2 nanoparticles and sodium dodecylbenzene sulfonate in the SSW nanofluids, and the concentration ratio of SiO2 nanoparticles to surfactant should be optimized to enhance heat transfer. Specifically at constant SDBS concentration of 50 ppm, and the relative better heat transfer performances can be obtained at SiO2 concentration of ωSiO2 = 100 ppm, in which the removed heat flux increased by 19%, the cooling time shortened from 8.1 to 5.7 seconds and the critical heat flux increased by 18% in comparison with deionized water. The optimized concentration ratio of SiO2 nanoparticles to SDBS to benefit heat transfer changes with variation of SiO2 nanoparticles in nanofluid at the relatively higher superheat temperature.

On diffusion of single-walled carbon nanotubes

The study is aimed at investigating the diffusion of single-walled nanotubes in liquids with the weight concentration of nanotubes varied from 0.00001 to 0.01%. Water solutions of sodium dodecylbenzene sulfate and polyvinylpyrrolidone, which are usually used as surfactants, are applied here as a carrier liquid. Their concentration is either equal to the concentration of nanotubes or twice greater. Depending on the concentration, the diffusion coefficient of nanotubes is found to change from 1.02·10−11 to 0.7·10−12 m2/s. Based on the data on the diffusion coefficient, the effective hydrodynamic size of nanotubes and their length are retrieved. The efficiency of nanotube separation by means of centrifugation and the changes in their characteristics during long-term storage are discussed.

Additives the panacea of coal water slurry

Indian high ash coal was used for the preparation of coal water slurry consisting of coarse and fine particles in the proper proportion. Four bimodal samples were prepared with the combination of four coarse fractions such as (212 µm–300 µm, 90 µm–300 µm, 150 µm–212 µm, 75 µm–150 µm) with fine fraction of (<38 µm) in different proportion and labeled as S1, S2, S3 and S4 respectively. Additives are the guiding factor for the flow of the slurry in pipeline. These samples were tried in the presence of different additives like bio, chemical and the combination of chemical and bio additives. In this study bio additives like Sapindous Mukorossi, Saponin from Shikakai, chemical additive like different alcohol groups, and combination of bio and chemical additive like saponin from Shikakai mixed with DDAB (Di dodecyl ammonium bromide), SDBS (Sodium do decyl benzene sulphate) were used. A comparative study revealed saponin from Shikaki when mixed with chemical additive DDAB in the proportion of 0.95:0.05 by weight gives a better result of 70% of coal loading.

Mixed Micelles of Binary Mixtures of Sodium Dodecylbenzene Sulfate and Tween 80 Surfactants in Aqueous Solutions

In the present work, the surface properties of mixed binary surfactants containing sodium dodecylbenzene sulfate (SDBS) and Tween 80 (TW80) surfactants in aqueous solutions were studied at temperature 293 K using surface tension measurements. The critical micelle concentration (cmc) magnitude for both individual surfactants and their mixtures were established the obtained results revealed that the magnitude of cmc of the mixtures are less than the magnitude of individual surfactants and decrease with the increase in Tween 80 percent in solution which indicate the nonideal mixing of the two surfactants. The values of molecular interaction parameters and the mole fraction of surfactants in the micelle (X1) were calculated on the basis of Rubingh’s model and showed that the interaction parameter is always negative but at 0.9 mole fraction of TW80 surfactant (α1) is positive

Surfactant-aided dispersion of carbon nanomaterials in aqueous solution

Carbon nanomaterials such as graphene and carbon nanotubes possess great thermophysical properties which make them very good candidates for heat transfer application. However, the major challenge of these nanomaterials is their tendency to agglomerate and bundle together when dispersed in base fluids. This study reviews the homogeneous dispersion of these nanomaterials in aqueous solution with the aid of surfactants. The different surfactants and their characterization methods for stable dispersion of carbon nanomaterials have been examined. The influence of surfactants on the thermophysical and rheological properties of carbon-based nanofluids was also highlighted. The usefulness of noncovalent functionalization using surfactants is due to its ability to efficiently unbundle carbon nanomaterials and sustain homogeneity of the nanofluids without compromising the integrity of their structure. Sodium dodecyl sulfate (SDS), sodium dodecyl benzene sulfate (SDBS), Gum Arabic (GA), Triton X-100, and cetyltrimethylammonium bromide (CTAB) are the commonly used surfactants. Unlike SDS, SDBS, and CTAB, GA does not foam when agitated. Various authors have investigated the stability of carbon-based nanofluids. Both physical and chemical techniques have been used to stabilize nanofluids. Mixed surfactants were found to stably disperse nanomaterials at lower concentrations compared to individual surfactants. However, limited studies exist for long term stability of carbon-based nanofluids.

Structure and stabilization mechanism of diesel oil-in-water emulsions stabilized solely by either positively or negatively charged nanoparticles

Two diesel oil-in-water emulsions were formed by using positively charged alumina nanoparticles solely and negatively charged silica nanoparticls solely as emulsifier, respectively. The formal systems are typical Pickering emulsions in which alumina nanoparticles adsorb at oil/water interface endowing droplets very good stability, whereas the later systems are non-Pickering emulsions in which silica nanoparticles do not adsorb at oil/water interface but distribute in aqueous phase surrounding the droplets endowing droplets temporary stability. Trace amounts of anionic surface-active materials in the diesel oil are responsible for the formation of two different emulsions. In the Pickering emulsions they adsorb at alumina particle surface to endow particle surface activity via in situ hydrophobization, whereas in the non-Pickering emulsions they adsorb at oil/water interface constituting a novel emulsion co-stabilized by like charged surfactants and nanoparticles at very low concentrations. By addition of trace amount of extra anionic surfactant, such as 0.1 mM sodium dodecyl benzene sulfate (SDBS), the novel diesel oil-in-water emulsions with good temporary stability can be formed by using silica nanoparticles at a concentration as low as 0.01 wt%. The emulsions can be demulsified easily by addition of trace amount (0.06∼0.1 mM) of a cationic surfactant such as cetyltrimethylammonium bromide (CTAB), or a low concentration (0.6∼3.0 mM) of divalent electrolyte such as CaCl2, and therefore have potential applications in oil transportation. On the other hand the Pickering diesel oil-in-water emulsions are relatively difficult to demulsify, and suitable demulsification protocols need to be developed for their applications in oil transportation.

Synthesis and characterization of anticorrosion emulsion latexes for metal

Copolymer emulsion latexes based on styrene: (St), and 2-ethylhexyl acrylate; (2- EHA), were prepared via emulsion polymerization with different compositions ratios (80:20 %, and 50:50 %). The polymerizations were carried out at 80 °C using ammonium persulfate (APS) as initiator technique system in presence of sodium dodecyl benzene sulfate (DBS) as surfactant. The copolymers lattices were characterized by FT-IR, 1HNMR, TGA, and DSC. Copolymer latexes were high solid content and used as binder in anticorrosive coating for metal. The presence of a new absorption peak in the infrared region of C-H stretching and C-H out of plane bending of polystyrene at 3027 and 696 cm-1 and the chemical shift of 1H NMR at 1.5-1.7 ppm due to presence of -CH2- in copolymer shows indicating that the polymerization has taken place. The thermogravimetric analysis (TGA) illustrated higher thermal stability that obtained by decomposition temperature. These copolymers have a single glass transition temperature indicating that these copolymers can form a homogenous phase. However, with increasing the ratio of 2-ethylhexyl acrylate in the copolymer, glass transition temperature increased. The obtained copolymers showed excellent adhesion properties on the metal. Also, the results showed that copolymer latex has good anti-corrosively, UV light stability, and direct application as metal anti-corrosive. However, increasing the ratio of 2-EHA enhanced anticorrosion properties of the metal.

Synthesis and Characterization of Polystyrene (PS)/Modified Ni‐Al LDH Nanocomposite: Role of Composition, Modifier and Synthesis Route of Layered Double Hydroxides (LDH)

Layered double hydroxides (LDH) are two‐dimensional nanostructured materials, which impart flame retardancy property and improvement in various properties on incorporation into the polymer matrix. In this study, Ni‐Al LDH with a molar ratio of 2:1 and 3:1 (2NiAl and 3NiAl) was prepared by co‐precipitation method and Ni‐Al LDH with a molar ratio of 2:1 (NiAl urea) was also synthesized by the urea hydrolysis method. As the d‐spacing of these as‐synthesized LDHs is very small (≈0.8 nm) as well as hydrophilic in nature, hence, the unmodified LDHs are unsuitable for polymer nanocomposite preparation. In order to enhance the d‐spacing of LDHs, a simple regeneration method was employed to organically modify LDHs using two anionic surfactants such as sodium dodecyl benzene sulfate (SDBS) and sodium dodecyl sulfate (SDS). The hydrophobic tail of these anionic surfactants replaced the nitrate ions present in the unmodified LDHs leading to higher d‐spacing value, which was evident from XRD analysis. The above prepared LDHs (3 wt%) were incorporated into PS matrix by the solvent blending method to make PS nanocomposites. The 003 peak of modified LDHs did not appear in the XRD pattern of PS nanocomposites due to the disorientation of LDH layers in the PS matrix that was confirmed by TEM analysis. The TGA results clearly demonstrated that the thermal stability of the PS nanocomposite samples was increased by 26, 22 and 22 °C (PS/2NiAl SDS, PS/3NiAl SDS, and PS/NiAl urea SDS) for SDS modified LDH fillers, while in the case of SDBS modified LDH fillers, the improvement was around 32 °C in comparison with PS, when 15% weight loss was taken as a reference. The degradation mechanism, thermal degradation kinetics, and integral procedural decomposition temperature (IPDT) for all the nanocomposite systems were also evaluated using Criado method, Coats‐Redfern method, and Doyle's method, respectively. The effect of dispersion of the modified LDH fillers into PS matrix was examined using melt rheological analysis.

Preparation of branched polystyrene by free radical emulsion polymerization in the presence of functional monomer

ABSTRACTSeveral branched polystyrenes were prepared by free radical emulsion polymerization in the presence of α-mercaptohexyl methacrylate (MHM) as the chain transfer monomers, potassium peroxodisulfate as the initiator and sodium dodecyl benzene sulfate as the emulsifier. Branched polystyrenes of high molecular weight and high branching degree were obtained. The obtained polymers were characterized by using three detection size exclusion chromatography (TD-SEC). The branched polystyrenes showed considerably higher molecular weights and higher branching degrees using this reaction system. The higher the mole ratio of MHM to monomer or the higher mole ratio of MHM to initiator, the higher were the obtained absolute weight average molecular weight and the branching degree of the obtained polystyrenes. In addition, low temperature of polymerization reaction also contributed to the high average molecular weight and the high average branching degree of branched polystyrene. The higher average molecular weight of branched polystyrene obtained in this system was accompanied by the higher average branching degree of the branched polystyrene. It was also shown that the nature of branched structures was not affected by the amount of initiator and reaction temperature of the polymer.

Surfactant-decorated graphite nanoplatelets (GNPs) reinforced aluminum nanocomposites: sintering effects on hardness and wear

The exceptional properties of graphene make it ideal as a reinforcement to enhance the properties of aluminum matrices and this critically depends on uniform dispersion. In this study, the dispersion issue was addressed by sonication and non-covalent surface functionalization of graphite nanoplatelets (GNPs) using two types of surfactant: anionic (sodium dodecyl benzene sulfate (SDBS)) and non-ionic polymeric (ethyl cellulose (EC)). After colloidal mixing with Al powder, consolidation was performed at two sintering temperatures (550 and 620°C). The structure, density, mechanical and wear properties of the nanocomposite samples were investigated and compared with a pure Al and a pure GNPs/Al nanocomposite sample. Noticeably, EC-based 0.5wt% GNPs/Al samples showed the highest increment of 31% increase in hardness with reduced wear rate of 98.25% at 620°C, while a 22% increase in hardness with reduced wear rate of 96.98% at 550°C was observed, as compared to pure Al. Microstructural analysis and the overall results validate the use of EC-based GNPs/Al nanocomposites as they performed better than pure Al and pure GNPs/Al nanocomposite at both sintering temperatures.

Experimental studies on flow and heat transfer characteristics of secondary refrigerant-based CNT nanofluids for cooling applications

ABSTRACTThe aim of the research work is to explore the convective heat transfer coefficient characteristics of propanol-based nanofluids for cooling applications. The stable suspension of the nanofluid with volume fractions of 0.15 and 0.3 is prepared and characterised. The measurement on the density shows that there is only a negligible increase in the density of the nanofluid and the specific heat of the nanofluid increases with the volumetric concentration of nanofluids. Furthermore, there is an enhancement in the convective heat transfer coefficient of 70% for the nanofluid containing 0.3% of CNT.Abbreviations: CNT: carbon nanotubes; IPA: isopropyl alcohol; MWCNT: multi-walled carbon nanotubes; SDBS: sodium dodecyl benzene sulphate

Direct exfoliation of graphite into graphene in aqueous solution using a novel surfactant obtained from used engine oil

Large-scale production of high-quality graphene is very critical for practical applications of graphene materials and devices. Exfoliation of graphite in an aqueous solution of surfactants is one of the most promising approaches to produce graphene. In this study, a novel anionic surfactant [sulfonated used engine oil (SUEO)], which was prepared from used engine oil, was employed to exfoliate the graphite nanoplatelets into graphene sheets in an aqueous solution under sonication to form a stable dispersion. The efficiency of SUEO for exfoliating and dispersing graphene was investigated and compared with that of traditional surfactants, such as sodium dodecyl sulfate, sodium dodecyl benzene sulfate, cetyl trimethyl ammonium bromide, and polyvinylpyrrolidone. Result showed that the graphene dispersion with excellent stability had a higher concentration (0.477 mg/mL) than others at 0.5 g/L optimal SUEO dosage in 4 h sonication time. The superior performance of SUEO can be attributed to its special molecular structures, whose hydrophobic moieties contain cycloalkanes/aromatics with different molecular weights and/or side chain –R with different lengths. Structural diversities are very helpful to the “jigsaw-puzzle” process on the graphene surface, where the total interfacial energy of the mixture system was minimized. Microscopic (SEM, TEM, and AFM) and spectroscopic (XRD, XPS, and Raman) measurements revealed that the dispersion consisted of few-layer graphene sheets with lower levels of defects or oxidation. This study presents a new class of dispersing agents for graphene that assists in the exfoliation process in water with high concentration and the stabilization of the graphene sheets against reaggregation.

Differential modulation of the chaperone-like activity of HSP-1/2, a major protein of horse seminal plasma by anionic and cationic surfactants

The major protein of equine seminal plasma, HSP-1/2 exhibits chaperone-like activity (CLA) by protecting various target proteins against thermal, chemical and oxidative stress. Polydispersity and surface hydrophobicity of HSP-1/2 were found to be important for its CLA. Surfactants are known to alter certain properties of proteins, e.g. hydrophobicity, charge and conformation either by altering properties of the medium or by direct binding. In the current study, thermal aggregation of alcohol dehydrogenase (ADH) and enolase has been studied in the presence of HSP-1/2, different surfactants and their combinations. The results obtained show that anionic surfactants (SDS, sodium dodecyl benzene sulfate) and neutral surfactants (tween-20, triton X-100) increase the CLA of HSP-1/2 and also inhibit aggregation of the target proteins independently. On the other hand, cationic surfactants (CTAB, alanine palmityl ester) increased the thermal aggregation of ADH and enolase and also decreased the CLA of HSP-1/2. These results are of significant interest as they show that surfactants such as SDS and tween-20 can potentially be used as anti-aggregation agents to prevent thermal aggregation of target proteins.

Experimental Investigation on Solidification Behaviour of Water Base Nanofluid PCM for Building Cooling Applications

The objective of the present work is to explore the solidification behaviour of Nanoparticle Enhanced Phase Change Material (NFPCM) for various cooling application at various experimental conditions. The NFPCM was prepared by dispersing the graphene nanoplatelets at various concentrations of 0.2 wt. %, 0.4 wt. % and 0.6 wt. % in DI water as the base PCM. The surfactant used was sodium dodecyl benzene sulphate (SDBS) and thermal conductivity of prepared NFPCM was measured at different surrounding bath temperature. The experimental results showed that 9.5 % enhancement in thermal conductivity with addition of 0.6 wt. % of graphene nanoplatelets when compared with base PCM, due to increase in surface area and high thermal conductivity of graphene nanoplatelets. Further experimental have been carried out in order to find out the solidification behaviour of the NFPCM. It was observed that the existence of GNPs decreases the subcooling appreciably and the reduction in solidification time was achieved 18 % and 24 % of NFPCM with 0.6 wt. % of GNP for the bath temperature of -9 oC and -12 oC respectively.

Vesicle-templating poly (3,4-ethylenedioxythiophene) hollow microspheres with enhanced electrocatalytic activity toward ascorbic acid oxidation

ABSTRACTPoly(3,4-ethylenedioxythiophene) (PEDOT) hollow microspheres ranging from 50 to 950 nm are synthesized by chemically oxidative polymerization of 3,4-ethylenedioxythiophene using ammonium persulfate in the aqueous solution of cetyltrimethylammonium bromide (CTAB) and sodium dodecylbenzenesulfate (SDBS). Vesicles formed by CTAB and SDBS serve as templates for the formation of PEDOT hollow microspheres. The obtained PEDOT hollow microspheres were characterized by Fourier transform infrared spectroscopy, elemental analysis, X-ray photoelectron spectroscopy, and conductivity measurement. Compared to PEDOT granular particles, PEDOT hollow microspheres showed a more effective electrocatalytic activity in lowering the ascorbic acid oxidation potential.

Mixed Surfactant Solutions for the Dispersion of Multiwalled Carbon Nanotubes and the Study of Their Antibacterial Activity.

The dispersibility of mixed surfactant-modified multiwalled carbon nanotubes (MWNTs) and their effect on antibacterial activity were examined. The ratio of 9:1 between sodium dodecyl benzene-sulfate (SDBS) and hexadecyltrimethylammonium bromide (CTAB) showed the highest dispersing power for MWNTs. The use of mixed surfactants enabled the MWNTs to form a stable dispersion at a lower total surfactant concentration than their concentrations when used alone. UV-vis spectroscopy, transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FT-IR) were used to characterize the dispersion of MWNTs in the aqueous phase. The results indicated that the surfactant molecules had been successfully adsorbed onto the surface of the MWNTs. The mixed surfactant-modified MWNTs exhibited a strong antibacterial activity and concentration dependence to Staphylococcus aureus (S. aureus). Based on the considerations of the cost and environmental impact, the use of mixed surfactants (SDBS-CTAB) should be more favorable for the stable dispersion of MWNTs and the improvement of antibacterial activity than the use of a single surfactant.

Thermal Conductivity of Carbon Nanotube Based Nanofluids as Heat Transfer Fluids

Conventional heat transfer fluids such as water and ethylene glycol exhibit low thermal conductivity. These fluids have certain influences on the efficiency of the thermal system. Efficiency of the thermal system is dependent on the thermal conductivity of the heat transfer fluid. New generation of heat transfer fluid such as nanofluid has potential to address this major problem. Therefore in this study, the thermal conductivity characteristic and stability of multiwalled carbon nanotube based water nanofluids was investigated. Two types of surfactants namely gum arabic and sodium dodecylbenzene sulphate (SDBS) were used to stabilize the nanofluid. Findings implied that thermal conductivity of water increases with the loading of multiwalled carbon nanotube nanoparticles. As for the stability, study shows that nanofluids added with SDBS are more stable compared to that of samples with gum Arabic.