The distribution of the number of oxyethylene groups in molecules of polyoxyethylene (5) nonylphenyl ether (NP5) is shown to significantly affect the structure of NP5/cyclohexane/water reverse microemulsions. The effect is caused by the difference in solubility of NP5 components. This difference leads to fractionation: surfactant molecules dissolved in the intermicellar nonpolar medium have, on average, shorter polyoxyethylene chains than surfactant molecules forming reverse micelles. A model is proposed which takes into account the influence of this fractionation on reverse micelle size and free surfactant concentration. The validity of this model for NP5/cyclohexane/water reverse microemulsions is experimentally confirmed by dynamic light scattering. It is found that changing the degree of surfactant fractionation in the above mentioned microemulsions can result in the formation of non-spherical reverse micelles.
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http://dx.doi.org/10.1016/j.jcis.2012.11.055 | DOI Listing |
Molecules
November 2024
Key Laboratory of Enhanced Oil Recovery, Northeast Petroleum University, Ministry of Education, Daqing 163318, China.
Aiming at the problem of excessive swelling of conventional microspheres for oilfield use, a novel amphiphilic polymerizable crosslinker (AE) was synthesized by quaternary ammonium modification of an unstable crosslinker (AE) using acrylamide, 2-acrylamido-2-methylpropanesulfonic acid as the monomers, N,N'-methylene bisacrylamide as the stabilizing crosslinker, ammonium peroxysulfate and sodium bisulfite as the initiator, and water as the solvent by using a reversed microemulsion method. Double-networked nanomicrospheres were prepared. The preparation conditions of the microspheres were optimized by the surface response method, focusing on the effects of the initiator addition and reaction temperature, and total crosslinker addition on the formation of nanomicrospheres.
View Article and Find Full Text PDFLangmuir
November 2024
Key Laboratory of Synthetic and Biological Colloids, Ministry of Education, School of Chemical & Materials Engineering, Jiangnan University, Wuxi 214122, P. R. China.
pH-switchable surfactant-based microemulsions (SBMEs) are those that can switch reversibly between a monophasic state and a fully phase-separated state under the alternation of acids and bases, which is rarely reported. By using an equimolar mixture of sodium dodecyl sulfate and N,N-dimethyldodecylamine (SDS-CA) as a pH-switchable surfactant, a pH-switchable SDS-CA-based microemulsion (SDS-CA-ME) has been fabricated for the first time. The main principles of the reversible switching are the reversible destruction/formation of the emulsifier, SDS-CA--butanol, film at the oil-water interface due to the alternating protonation/deprotonation of CA caused by acids and bases.
View Article and Find Full Text PDFACS Omega
November 2024
Key Laboratory for EOR Technology (Ministry of Education), Northeast Petroleum University, Xuefu Road 99, Daqing 163318, China.
Phase separation of microemulsions occupies a key position in many applications, such as oil recovery, nanomaterial synthesis, and chemical reactions. Achieving an intelligent response is crucial to microemulsion development and application. For this reason, in this study, CO-responsive superamphiphilic molecules were developed as rapidly switchable oil-in-water microemulsions.
View Article and Find Full Text PDFElectrophoresis
November 2024
Department of Chemistry of Coordination, Cluster and Supramolecular Compounds, Nikolaev Institute of Inorganic Chemistry, Novosibirsk, Russia.
Int J Pharm
December 2024
State Key Laboratory on Technologies for Chinese Medicine Pharmaceutical Process Control and Intelligent Manufacture, Nanjing University of Chinese Medicine, Nanjing 210023, China; School of Pharmacy, Jiangsu Provincial TCM Engineering Technology Research Center of High Efficient Drug Delivery System (DDS), Nanjing University of Chinese Medicine, Nanjing 210023, China. Electronic address:
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