The Experts below are selected from a list of 642 Experts worldwide ranked by ideXlab platform
Christopher T. Culbertson - One of the best experts on this subject based on the ideXlab platform.
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A novel, environmentally friendly sodium lauryl ether sulfate-, Cocamidopropyl Betaine-, cocamide monoethanolamine-containing buffer for MEKC on microfluidic devices.
Electrophoresis, 2008Co-Authors: Kurt Hoeman, Christopher T. CulbertsonAbstract:A new buffer has been developed for fast, high-efficiency separations of amino acids by MEKC. This buffer was more environmentally friendly than the most commonly used surfactant-containing buffers for MEKC separations. It used a commercially available dishwashing soap by Seventh Generation™ (Burlington, VT, USA), which contained three micelle-forming agents. The mixed micelles were composed of sodium lauryl ether sulfate (anionic), Cocamidopropyl Betaine (zwitterionic), and cocamide monoethanolamine (non-ionic). The optimized buffer contained 5.0% w/w Seventh Generation™ Free & Clear™ dishwashing soap, 10 mM sodium borate, and was completely void of organics. The lack of organics and the biodegradability of the surfactant molecules made this buffer more environmentally friendly than typical SDS-containing buffers. This new buffer also had a different selectivity and provided faster separations with higher separation efficiencies than SDS-based buffers. Fast separations of BODIPY FL labeled amino acids yielded peaks with separation efficiencies greater than 100 000 in less than 20 s.
Masoomeh Alizadeh - One of the best experts on this subject based on the ideXlab platform.
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Cocamidopropyl Betaine Catalyzed Benzoin Condensation and Pseudo-Four-Component Reaction of the in Situ Formed Benzoin in Water
Synlett, 2015Co-Authors: Fatemeh Tamaddon, Masoomeh AlizadehAbstract:An improved synthesis of benzoins, as key synthetic building blocks, and substituted pyrroles in micelle medium using a very small amount of Cocamidopropyl Betaine in water is described. In this one-pot strategy, benzoin condensation of aldehydes and further pseudo-four-component reaction of the in situ formed benzoin with 1,3-dicarbonyls, and ammonium acetate gave excellent yields of the desired pyrrole products.
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A four-component synthesis of dihydropyrano(2,3-c)pyrazoles in a new water- based worm-like micellar medium
Tetrahedron Letters, 2014Co-Authors: Fatemeh Tamaddon, Masoomeh AlizadehAbstract:Abstract Cocamidopropyl Betaine (CAPB) as a biodegradable surfactant produces a new worm-like micellar medium for rapid synthesis of dihydropyrano[2,3-c]pyrazoles via a four-component reaction of aldehydes, ethyl acetoacetate, malononitrile, and hydrazine hydrate at 50–60 °C. This zwitterionic surfactant was superior to anionic, cationic, and nonionic alternatives for accessing high yields of pure products without the use of any organic solvent. While the reaction medium was reusable, simple isolation of products, mild reaction conditions, low loading of CAPB for critical micelle concentration and short reaction times are additional advantages of this green procedure.
Paola Carbone - One of the best experts on this subject based on the ideXlab platform.
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The Relationship between Wormlike Micelle Scission Free Energy and Micellar Composition: The Case of Sodium Lauryl Ether Sulfate and Cocamidopropyl Betaine
Langmuir : the ACS journal of surfaces and colloids, 2020Co-Authors: Charlie Ray Wand, Maria Panoukidou, Richard L. Anderson, Annalaura Del Regno, Paola CarboneAbstract:The scission energy is the difference in free energy between two hemispherical caps and the cylindrical region of a wormlike micelle. This energy difference determines the logarithm of the average micelle length, which affects several macroscopic properties such as the viscosity of viscoelastic fluids. Here we use a recently published method by Wang et al. ( Langmuir, 2018, 34, 1564-1573) to directly calculate the scission energy of micelles composed of monodisperse sodium lauryl ether sulfate (SLESnEO), an anionic surfactant. Utilizing dissipative particle dynamics (DPD), we perform a systematic study varying the number of ethoxyl groups (n) and salt concentration. The scission energy increases with increasing salt concentration, indicating that the formation of longer micelles is favored. We attribute this to the increased charge screening that reduces the repulsion between head groups. However, the scission energy decreases with increasing number of ethoxyl groups as the flexibility of the head group increases and the sodium ion becomes less tightly bound to the head group. We then extend the analysis to look at the effect of a common cosurfactant, Cocamidopropyl Betaine (CAPB), and find that its addition stabilizes wormlike micelles at a lower salt concentration.
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The Relationship Between Wormlike Micelle Scission Free Energy and Micellar Composition: The Case of Sodium Laurylethersulphate and Cocamidopropyl Betaine
2020Co-Authors: Charlie Wand, Maria Panoukidou, Annalaura Del Regno, Richard L. Anderson, Paola CarboneAbstract:The scission energy is the difference in energy between two hemispherical caps and the cylindrical region of a wormlike micelle. This energy difference is exponentially proportional to the average micelle length, which affects several macroscopic properties such as the viscosity of viscoelastic fluids. Here we use a recently published method by Wang et al (Langmuir 2018 34 1564-1573) to directly calculate the scission energy of micelles composed of monodisperse Sodium Laurylethersulphate (SLESnEO), an anionic surfactant. We perform a systematic study varying the number of ethoxyl groups (n) and salt concentration. The scission energy increases with increasing salt concentration, indicating that the formation of longer micelles is favoured. We attribute this to the increased charge screening that reduces the repulsion between head groups. However, the scission energy decreases with increasing number of ethoxyl groups as the flexibility of the head group increases and the sodium ion becomes less tightly bound to the head group. We then extend to look at the effect of a common co-surfactant, Cocamidopropyl Betaine (CAPB) and find that its addition increases the scission energy, stabilising wormlike micelles at a lower salt concentration.
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The Relationship Between Wormlike Micelle Scission Free Energy and Micellar Composition: The Case of Sodium Laurylethersulphate and Cocamidopropyl Betaine
2020Co-Authors: Charlie Wand, Maria Panoukidou, Annalaura Del Regno, Richard L. Anderson, Paola CarboneAbstract:The scission energy is the difference in energy between two hemispherical caps and the cylindrical region of a wormlike micelle. This energy difference determines the logarithm of the average micelle length, which affects several macroscopic properties such as the viscosity of viscoelastic <br>fluids. Here we use a recently published method by Wang et al (Langmuir 2018 34 1564-1573) to directly calculate the scission energy of micelles composed of monodisperse Sodium Laurylethersulphate (SLESnEO), an anionic surfactant. We perform a systematic study varying the number of ethoxyl groups (n) and salt concentration. The scission energy increases with increasing salt concentration, indicating that the formation of longer micelles is favoured. We attribute this to the increased charge screening that reduces the repulsion between head groups. However, the scission energy decreases with increasing number of ethoxyl groups as the flexibility of the head group increases and the sodium ion becomes less tightly bound to the head group. We then extend the analysis to look at the effect of a common co-surfactant, Cocamidopropyl Betaine (CAPB) and find that its addition increases the scission energy, stabilising wormlike micelles at a lower salt concentration.
Ronald G. Larson - One of the best experts on this subject based on the ideXlab platform.
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Multiscale Modeling of the Effects of Salt and Perfume Raw Materials on the Rheological Properties of Commercial Threadlike Micellar Solutions.
The journal of physical chemistry. B, 2017Co-Authors: Xueming Tang, Weizhong Zou, Michael Rene Weaver, Peter H. Koenig, Shawn David Mcconaughy, David M. Eike, Michael J. Schmidt, Ronald G. LarsonAbstract:We link micellar structures to their rheological properties for two surfactant body-wash formulations at various concentrations of salts and perfume raw materials (PRMs) using molecular simulations and micellar-scale modeling, as well as traditional surfactant packing arguments. The two body washes, namely, BW-1EO and BW-3EO, are composed of sodium lauryl ethylene glycol ether sulfate (SLEnS, where n is the average number of ethylene glycol repeat units), Cocamidopropyl Betaine (CAPB), ACCORD (which is a mixture of six PRMs), and NaCl salt. BW-3EO is an SLE3S-based body wash, whereas BW-1EO is an SLE1S-based body wash. Additional PRMs are also added into the body washes. The effects of temperature, salt, and added PRMs on micellar lengths, breakage times, end-cap free energies, and other properties are obtained from fits of the rheological data to predictions of the “Pointer Algorithm” [Zou, W.; Larson, R.G. J. Rheol. 2014, 58, 1−41], which is a simulation method based on the Cates model of micellar dynam...
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Determination of characteristic lengths and times for wormlike micelle solutions from rheology using a mesoscopic simulation method
Journal of Rheology, 2015Co-Authors: Weizhong Zou, Xueming Tang, Michael Rene Weaver, Peter H. Koenig, Ronald G. LarsonAbstract:We apply our recently developed mesoscopic simulation method for entangled wormlike micelle (WLM) solutions to extract multiple micellar characteristic lengths and time constants: i.e., average micelle length, breakage rate, and entanglement and persistence lengths, from linear rheological measurements on commercial surfactant solutions, one containing sodium lauryl one ether sulfate (SLE1S), and the other containing both SLE1S and Cocamidopropyl Betaine, as well as a perfume mixture, in both cases with a sample salt (NaCl) added. Measurements include both mechanical rheometry and diffusing wave spectroscopy, the latter providing the high-frequency data needed to determine micelle persistence length accurately. By fitting the experimental data ( G′ and G″) across the entire frequency range through our iteration procedure, the method is of practical use in predicting micellar parameters, which are difficult to obtain from other theoretical or experimental methods. The dependence of micellar parameters on a...
Jan Ruzicka - One of the best experts on this subject based on the ideXlab platform.
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Degradation of the surfactant Cocamidopropyl Betaine by two bacterial strains isolated from activated sludge
International Biodeterioration & Biodegradation, 2018Co-Authors: Marketa Merkova, Michal Zalesak, Eva Ringlova, Markéta Julinová, Jan RuzickaAbstract:Abstract Cocamidopropyl Betaine (CAPB) is an amphiphilic surfactant commonly used in a variety of personal care products and in some technical applications. The aim of the study was to obtain bacteria that utilized CAPB from a sample of municipal activated sludge, and to investigate the possible role such bacteria performed in surfactant degradation. The CAPB (300 mg l −1 ) degradation experiments involved the application of two isolated strains. Whilst tests in a mineral medium containing ammonium salt as a nitrogen source revealed almost complete mineralization of the compound in both strains during 4 days, the same process required more than 29 days of incubation under nitrogen-free conditions. Degradation assays and a series of growth tests with and without the source of nitrogen showed that Pseudomonas sp. FV proved to be the primary degrader of CAPB, capable of utilizing the alkyl chains of the surfactant. The other strain, Rhizobium sp. FM, ensured the degradation of intermediates originating from the primary biodegradation stage and, in the absence of ammonium salt, provided a supply of nitrogen to its microbial partner.