The Experts below are selected from a list of 9303 Experts worldwide ranked by ideXlab platform
Xuefeng Liu - One of the best experts on this subject based on the ideXlab platform.
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a worm containing viscoelastic fluid based on single Amine Oxide surfactant with an unsaturated c22 tail
RSC Advances, 2015Co-Authors: Yongmin Zhang, Xuefeng LiuAbstract:“Worm”-containing viscoelastic fluids formed by single C22-tailed surfactants have attracted special interests over the past decade due to their unique rheological response. Here, a viscoelastic wormlike micellar solution of erucyldimethyl amidopropyl Amine Oxide (EMAO) was first reported and investigated. Upon increasing concentration, EMAO can self-assembly into micelles at a very low concentration, and then these micelles grow into long threadlike worms, which further entangle with each other in the semi-dilute region (>0.55 mM), enhancing the viscosity by several orders of magnitude. EMAO worms exhibit a smaller sensitivity to pH at room temperature than those of short-chain counterparts, but show evident pH responsiveness at high temperature due to the presence of multiple hydrogen bonds and cloud point, which is barely observed for short-chain Amine Oxide surfactants. The hydrogen bonds and cloud point also result in an uncommon thermo-thickening behaviour in a certain temperature range. Compared with short-chain Amine Oxide worms, EMAO worm possesses stronger thickening ability, better biodegradable and lower toxicity, giving it a rich prospective for use in gel cleaners, clear fracturing fluids, etc.
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A “worm”-containing viscoelastic fluid based on single Amine Oxide surfactant with an unsaturated C22-tail
RSC Advances, 2015Co-Authors: Yongmin Zhang, Xuefeng LiuAbstract:“Worm”-containing viscoelastic fluids formed by single C22-tailed surfactants have attracted special interests over the past decade due to their unique rheological response. Here, a viscoelastic wormlike micellar solution of erucyldimethyl amidopropyl Amine Oxide (EMAO) was first reported and investigated. Upon increasing concentration, EMAO can self-assembly into micelles at a very low concentration, and then these micelles grow into long threadlike worms, which further entangle with each other in the semi-dilute region (>0.55 mM), enhancing the viscosity by several orders of magnitude. EMAO worms exhibit a smaller sensitivity to pH at room temperature than those of short-chain counterparts, but show evident pH responsiveness at high temperature due to the presence of multiple hydrogen bonds and cloud point, which is barely observed for short-chain Amine Oxide surfactants. The hydrogen bonds and cloud point also result in an uncommon thermo-thickening behaviour in a certain temperature range. Compared with short-chain Amine Oxide worms, EMAO worm possesses stronger thickening ability, better biodegradable and lower toxicity, giving it a rich prospective for use in gel cleaners, clear fracturing fluids, etc.
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Synthesis and Surface Properties of N,N-Dimethyl-N-dodecyl Polyoxyethylene Amine-Based Surfactants: Amine Oxide, Betaine and Sulfobetaine
Journal of Surfactants and Detergents, 2013Co-Authors: Liya Hou, Huinian Zhang, Hui Chen, Qibo Xia, Dongyang Huang, Li Meng, Xuefeng LiuAbstract:Nonionic–zwitterionic hybrid surfactants, namely N,N-dimethyl-N-dodecyl polyoxyethylene (3) Amine Oxide, and the corresponding betaine and/or sulfobetaine, have been synthesized. Their molecule structures were characterized by means of electrospray ionization mass spectrometry and 1H nuclear magnetic resonance. Compared to the structurally related conventional Amine Oxide, betaine and sulfobetaine, the critical micelle concentrations of the three hybrid surfactants are one order of magnitude smaller than those of traditional ones. The polyoxyethylene segment between the hydrophilic head group and the hydrophobic tail makes the surface activities of the hybrid surfactants superior to their structure-related counterparts.
Yongmin Zhang - One of the best experts on this subject based on the ideXlab platform.
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a worm containing viscoelastic fluid based on single Amine Oxide surfactant with an unsaturated c22 tail
RSC Advances, 2015Co-Authors: Yongmin Zhang, Xuefeng LiuAbstract:“Worm”-containing viscoelastic fluids formed by single C22-tailed surfactants have attracted special interests over the past decade due to their unique rheological response. Here, a viscoelastic wormlike micellar solution of erucyldimethyl amidopropyl Amine Oxide (EMAO) was first reported and investigated. Upon increasing concentration, EMAO can self-assembly into micelles at a very low concentration, and then these micelles grow into long threadlike worms, which further entangle with each other in the semi-dilute region (>0.55 mM), enhancing the viscosity by several orders of magnitude. EMAO worms exhibit a smaller sensitivity to pH at room temperature than those of short-chain counterparts, but show evident pH responsiveness at high temperature due to the presence of multiple hydrogen bonds and cloud point, which is barely observed for short-chain Amine Oxide surfactants. The hydrogen bonds and cloud point also result in an uncommon thermo-thickening behaviour in a certain temperature range. Compared with short-chain Amine Oxide worms, EMAO worm possesses stronger thickening ability, better biodegradable and lower toxicity, giving it a rich prospective for use in gel cleaners, clear fracturing fluids, etc.
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A “worm”-containing viscoelastic fluid based on single Amine Oxide surfactant with an unsaturated C22-tail
RSC Advances, 2015Co-Authors: Yongmin Zhang, Xuefeng LiuAbstract:“Worm”-containing viscoelastic fluids formed by single C22-tailed surfactants have attracted special interests over the past decade due to their unique rheological response. Here, a viscoelastic wormlike micellar solution of erucyldimethyl amidopropyl Amine Oxide (EMAO) was first reported and investigated. Upon increasing concentration, EMAO can self-assembly into micelles at a very low concentration, and then these micelles grow into long threadlike worms, which further entangle with each other in the semi-dilute region (>0.55 mM), enhancing the viscosity by several orders of magnitude. EMAO worms exhibit a smaller sensitivity to pH at room temperature than those of short-chain counterparts, but show evident pH responsiveness at high temperature due to the presence of multiple hydrogen bonds and cloud point, which is barely observed for short-chain Amine Oxide surfactants. The hydrogen bonds and cloud point also result in an uncommon thermo-thickening behaviour in a certain temperature range. Compared with short-chain Amine Oxide worms, EMAO worm possesses stronger thickening ability, better biodegradable and lower toxicity, giving it a rich prospective for use in gel cleaners, clear fracturing fluids, etc.
Debora Berti - One of the best experts on this subject based on the ideXlab platform.
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an Amine Oxide surfactant based microemulsion for the cleaning of works of art
Journal of Colloid and Interface Science, 2015Co-Authors: Michele Baglioni, Yareli Jaidar Benavides, Debora Berti, Rodorico Giorgi, Uwe Keiderling, Piero BaglioniAbstract:Surfactant-based aqueous fluids, such as micellar solutions and microemulsions, are effective, safe and selective media for cleaning operations in conservation of cultural heritage. The search for better-performing systems and eco-friendly cleaning systems is currently a major goal in conservation science. We report here on a ternary o/w microemulsion, composed of diethyl carbonate (DC) as the oil phase and N,N-Dimethyldodecan-1-Amine Oxide (DDAO) as the surfactant. DDAO is a well known and widely used detergent and solubilizing agent, selected here for its degradability and eco-compatibility. Due to its nonionic/cationic nature, it can be used also when nonionic-based formulations become ineffective because of clouding and phase separation. Moreover, DDAO is insensitive to the presence of divalent metal ions, usually abundant in wall paintings substrates. Small-Angle Neutron Scattering (SANS) provided detailed information about the nanostructure of the surfactant aggregates. Finally, the cleaning effectiveness of the nanofluid was assessed both on fresco mock-ups and on real wall paintings conserved in the archeological site of Tulum, Mexico. Here, conservators successfully used the microemulsion to remove naturally aged films of complex polymer mixtures from the works of art surface.
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Viscoelastic solutions formed by worm-like micelles of Amine Oxide surfactant.
Journal of Colloid and Interface Science, 2010Co-Authors: Lucia Brinchi, Raimondo Germani, Gianfranco Savelli, P. Di Profio, Luisa Marte, Debora BertiAbstract:Abstract Formation and properties of viscoelastic wormlike aqueous micellar solutions of the zwitterionic surfactant p-dodecyloxybenzyldimethylAmine Oxide (pDoAO) were studied. Semi-dilute aqueous solutions of pDoAO show a sharp increase in viscosity, which exceeds 160 cST for concentrations >50 mM, leading to viscoelastic solutions. Viscoelasticity relates to the surfactant charge type. In fact this viscoelastic system reverses to fluid when acid is added (pH
Christian V. Stevens - One of the best experts on this subject based on the ideXlab platform.
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Sophorolipid Amine Oxide Production by a Combination of Fermentation Scale-up and Chemical Modification
Industrial & Engineering Chemistry Research, 2016Co-Authors: Elisabeth Delbeke, Sophie Roelants, Nele Matthijs, Bernd Everaert, Wim Soetaert, Tom Coenye, Kevin Van Geem, Christian V. StevensAbstract:Production scale-up of high-purity diacetylated C18:1 sophorolipid lactone was demonstrated from lab to pilot scale with the Starmerella bombicola lactone esterase overexpression strain (oe sble) as production organism. The 150 L fermentation using oleic acid and yeast extract, characterized by a titer of 199 g/L and a volumetric productivity of 0.9 g/L·h, was most successful in obtaining a highly pure (>98%) and uniform (96% C18:1 SL lactone) sophorolipid product suitable for chemical derivatization. The fermentation product was subsequently modified to produce sophorolipid Amine Oxides, which cannot be produced enzymatically. First, the fermentation product was transformed into an intermediate sophorolipid aldehyde via methanolysis and protection of the sugar head through acetylation and ozonolysis. This aldehyde intermediate was then used for the synthesis of the sophorolipid Amine Oxides via reductive amination, oxidation, and deprotection of the sugar head. The total yield of this synthetic pathway a...
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Sophorolipid Amine Oxide Production by a Combination of Fermentation Scale-up and Chemical Modification
2016Co-Authors: Elisabeth Delbeke, Sophie Roelants, Nele Matthijs, Bernd Everaert, Wim Soetaert, Tom Coenye, Kevin Van Geem, Christian V. StevensAbstract:Production scale-up of high-purity diacetylated C18:1 sophorolipid lactone was demonstrated from lab to pilot scale with the Starmerella bombicola lactone esterase overexpression strain (oe sble) as production organism. The 150 L fermentation using oleic acid and yeast extract, characterized by a titer of 199 g/L and a volumetric productivity of 0.9 g/L·h, was most successful in obtaining a highly pure (>98%) and uniform (96% C18:1 SL lactone) sophorolipid product suitable for chemical derivatization. The fermentation product was subsequently modified to produce sophorolipid Amine Oxides, which cannot be produced enzymatically. First, the fermentation product was transformed into an intermediate sophorolipid aldehyde via methanolysis and protection of the sugar head through acetylation and ozonolysis. This aldehyde intermediate was then used for the synthesis of the sophorolipid Amine Oxides via reductive amination, oxidation, and deprotection of the sugar head. The total yield of this synthetic pathway amounts to 18–30%. These compounds constitute a class of innovative sophorolipid derivatives with potential for high added-value applications. The sophorolipid Amine Oxides have been evaluated for their antimicrobial activity against the Gram-negative bacteria Escherichia coli LMG 8063, Klebsiella pneumoniae LMG 2095, and Pseudomonas aeruginosa PAO1 and the Gram-positive bacteria Staphylococcus aureus ATCC 6538 and Staphylococcus aureus Mu50. The present approach of combining large-scale fermentation and subsequent chemical modification facilitates the creation of a platform of innovative sophorolipid derivatives in adequate quantities, opening the door for novel applications
Gerardino D'errico - One of the best experts on this subject based on the ideXlab platform.
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pH-responsive micellization of an Amine Oxide surfactant with branched hydrophobic tail
Journal of Molecular Liquids, 2020Co-Authors: Luca Scermino, Antonio Fabozzi, Gaetano De Tommaso, Artur J.m. Valente, Mauro Iuliano, Luigi Paduano, Gerardino D'erricoAbstract:Abstract pH-sensitive surfactants find applications in many fields, including responsive drug delivery and smart material design. The rational design of the surfactant molecular structure leads to species presenting strong variations of the micellization parameter (e.g., critical micelle concentration, cmc, and aggregate dimension) in a controlled pH range. In the present work, the micellization of the branched Amine Oxide surfactant N,N-dimethyl-2-propylheptan-1-Amine Oxide (C10DAO-branched) is studied as a function of pH in dilute aqueous mixtures. Its behavior is compared with that of the linear isomer N,N-dimethyldecan-1-Amine Oxide (C10DAO-linear). The samples are investigated by potentiometric titrations, fluorescence spectroscopy, and Dynamic Light Scattering (DLS). With increasing pH, micellized C10DAO-branched presents a higher tendency to remain in the protonated/cationic form with respect to the linear isomer. As a consequence, the minimum cmc value, observed when the protonated and the deprotonated/zwitterionic forms of the surfactant coexist in the micelles, is shifted to higher pH values. The volume of these C10DAO-branched “mixed micelles” is more than one order of magnitude higher than that of completely protonated or deprotonated aggregates. This is a singularity of the branched surfactant, not observed for the linear isomer. Overall, the results highlight that the branched molecular architecture of the surfactant tail, favoring the formation of low-curvature aggregates, enhances H-bonding between the protonated and deprotonated headgroups, which synergistically stabilizes the flatter surface of bulkier aggregates. Taking into account the good biodegradability of surfactants with a limited number of short side chains, purposely designed branched surfactants appear as a suitable option to accurately tune supramolecular aggregation in pH-responsive formulations.
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Effect of tail branching on the phase behavior and the rheological properties of Amine Oxide/ethoxysulfate surfactant mixtures
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 1Co-Authors: Luigi Savignano, Antonio Fabozzi, Luigi Paduano, Rosa Vitiello, Marco Fornasier, Sergio Murgia, Stefano Guido, Vincenzo Guida, Gerardino D'erricoAbstract:Abstract The formulation of highly concentrated products with low viscosity is a key issue of the surfactants industry, for both economic and ecological reasons. The rational design of surfactant tails bearing a limited number of short side chains has been proposed as a suitable strategy to meet this demand, with negligible effects on biodegradability. In this work, we investigate a mixed surfactant system, in which the branched surfactant N,N-dimethyl-2-propylheptan-1-Amine Oxide (C10DAO-branched) is combined with a linear alkyl ethoxysulfate one (AES). For comparison, we also study the mixtures in which the branched Amine Oxide is replaced by its linear isomer (C10DAO-linear). The phase behavior of this surfactant mixture in water is investigated across the entire composition range by polarized optical microscopy and small angle X-ray scattering. Moreover, the shear viscosities and viscoelastic moduli of representative samples are determined by rheological measurements. C10DAO-branched/AES aqueous mixtures form isotropic micellar solution and lamellar structures. Low viscosity was found for all these mixtures, including the most concentrated ones. In contrast, in C10DAO-linear/AES mixtures an extended hexagonal phase is detected, which presents a high viscosity. These results demonstrate tail branching and mixed aggregation to synergistically contribute to the design of high-concentration low-viscosity surfactant mixtures.
