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1
Cheng, Chao, i Shi-Yong Ran. "Interaction between DNA and Trimethyl-Ammonium Bromides with Different Alkyl Chain Lengths". Scientific World Journal 2014 (2014): 1–9. http://dx.doi.org/10.1155/2014/863049.
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The interaction betweenλ—DNA and cationic surfactants with varying alkyl chain lengths was investigated. By dynamic light scattering method, the trimethyl-ammonium bromides-DNA complex formation was shown to be dependent on the length of the surfactant’s alkyl chain. For surfactants with sufficient long alkyl chain (CTAB, TTAB, DTAB), the compacted particles exist with a size of ~60–110 nm at low surfactant concentrations. In contrast, high concentration of surfactants leads to aggregates with increased sizes. Atomic force microscope scanning also supports the above observation. Zeta potential measurements show that the potential of the particles decreases with the increase of surfactant concentration (CTAB, TTAB, DTAB), which contributes much to the coagulation of the particles. For OTAB, the surfactant with the shortest chain in this study, it cannot fully neutralize the charges of DNA molecules; consequently, the complex is looser than other surfactant-DNA structures.
2
Taba, Paulina, Russell F. Howe i Graine Moran. "FTIR AND NMR STUDIES OF ADSORBED CETHYLTRIMETHYLAMMONIUM CHLORIDE IN MCM-41 MATERIALS". Indonesian Journal of Chemistry 8, nr 1 (17.06.2010): 1–6. http://dx.doi.org/10.22146/ijc.21639.
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The high use of surface-active agents (surfactants) by industry and households today leads to environmental pollution, therefore treatments are required to remove such substances from the environment. One of the important and widely used methods for removal of substances from solution is adsorption. In this research, MCM-41 and its modified product of MCM41-TMCS were used to adsorb cationic surfactants, cethyltrimethylammonium chloride, CTAC. FTIR and NMR methods were used to study the interaction between the surfactants and the adsorbents. MCM-41 was synthesized hydrothermally at 100 oC and its modification was conducted by silylation of MCM-41 with trimethylchloro silane (MCM41-TMCS). Both unmodified and modified MCM-41 can adsorb the surfactant. The interaction of CTAC with MCM-41 was mostly the electrostatic interaction between the electropositive end of the surfactant and MCM-41, whereas in modified MCM-41 hydrophobic interactions become more dominant. These hydrophobic interactions appear however to involve the methyl groups on the head group of the surfactant interacting with the modified surface. Keywords: FTIR, NMR, adsorbed CTAC, MCM-41 materials
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Yang, Jia, i Rajinder Pal. "Investigation of Surfactant-Polymer Interactions Using Rheology and Surface Tension Measurements". Polymers 12, nr 10 (8.10.2020): 2302. http://dx.doi.org/10.3390/polym12102302.
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The interactions between surfactants and a drag-reducing polymer were investigated at a low polymer concentration of 500 ppm, using measurements of the rheology and surface activity of surfactant-polymer solutions. A well-known drag-reducing polymer (anionic sodium carboxymethyl cellulose) and five different surfactants (two anionic, two non-ionic, and one zwitterionic) were selected for the interaction studies. The surfactant-polymer solutions were shear thinning in nature, and they followed the power law model. The interaction between the surfactant and polymer had a strong effect on the consistency index of the solution and a marginal effect on the flow behavior index. The surface tension versus surfactant concentration plots were interpreted in terms of the interactions between surfactant and polymer. The critical aggregation concentration (CAC) of the surfactant was estimated based on the surface tension and rheological data. The CAC values of the same charge surfactants as that of the polymer were found to be significantly higher than other combinations of surfactant and polymer, such as non-ionic surfactant/anionic polymer, and zwitterionic surfactant/anionic polymer.
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Lai, Chiu-Chun, Kuo-Shien Huang, Po-Wei Su, Chang-Mou Wu i Ching-Nan Huang. "Interactions of modified Gemini surfactants: Interactions with direct dyes and dyeing properties in cotton fabrics". Modern Physics Letters B 33, nr 14n15 (28.05.2019): 1940002. http://dx.doi.org/10.1142/s0217984919400025.
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This study investigated dye–surfactant interactions between a series of modified Gemini surfactants and commercial direct dyes in aqueous solution and their corresponding effects on cotton fabric dyeing. A surface tension meter was also used to measure surface activities of compounds containing electrolyte under conditions similar to those in dyeing processes. The surface tension measurements showed lower than normal surface tension in surfactant solutions containing electrolyte. From the UV-Vis spectra, the isosbestic point indicated that dye–surfactant complexes had formed and existed as hydrophilic interaction between direct dyes and modified Gemini surfactants. When dyeing cotton fabric with red dye and orange dye, the presence of these surfactants decreased dye uptake rate but increased for blue dye because the dye–surfactant interaction had formed a hydrophilic complex.
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Ostos, Francisco José, José Antonio Lebrón, María Luisa Moyá, Eva Bernal, Ana Flores, Cristian Lépori, Ángeles Maestre, Francisco Sánchez, Pilar López-Cornejo i Manuel López-López. "Potentiometric Study of Carbon Nanotube/Surfactant Interactions by Ion-Selective Electrodes. Driving Forces in the Adsorption and Dispersion Processes". International Journal of Molecular Sciences 22, nr 2 (15.01.2021): 826. http://dx.doi.org/10.3390/ijms22020826.
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The interaction (adsorption process) of commercial ionic surfactants with non-functionalized and functionalized carbon nanotubes (CNTs) has been studied by potentiometric measurements based on the use of ion-selective electrodes. The goal of this work was to investigate the role of the CNTs’ charge and structure in the CNT/surfactant interactions. Non-functionalized single- (SWCNT) and multi-walled carbon nanotubes (MWCNT), and amine functionalized SWCNT were used. The influence of the surfactant architecture on the CNT/surfactant interactions was also studied. Surfactants with different charge and hydrophobic tail length (sodium dodecyl sulfate (SDS), octyltrimethyl ammonium bromide (OTAB), dodecyltrimethyl ammonium bromide (DoTAB) and hexadecyltrimethyl ammonium bromide (CTAB)) were studied. According to the results, the adsorption process shows a cooperative character, with the hydrophobic interaction contribution playing a key role. This is made evident by the correlation between the free surfactant concentration (at a fixed [CNT]) and the critical micellar concentration, cmc, found for all the CNTs and surfactants investigated. The electrostatic interactions mainly determine the CNT dispersion, although hydrophobic interactions also contribute to this process.
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LIU, HAO-YANG, XIAN-WU ZOU, YIN-QUAN YUAN i ZHUN-ZHI JIN. "EFFECTS OF INTERACTION WITH SOLVENT AND CHAIN CONFORMATION OF SURFACTANTS ON EMULSIFICATION". Modern Physics Letters B 15, nr 24 (20.10.2001): 1061–68. http://dx.doi.org/10.1142/s0217984901002853.
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The details of the emulsification process has been investigated by discontinuous molecular dynamic simulation. The surfactants help to bring about emulsification. The emulsification can be divided crudely into two stages: splitting and uniting process. The splitting and uniting of oil droplets occurs in this position, where surfactants at the interface is rather scarce. The effects of the conformation of surfactant chain and the strength of surfactant–water and surfactant–oil interactions on emulsification were also studied. The surfactants with longer tail and stronger surfactant–water and surfactant–oil interactions promote the emulsification more.
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Hosseinzadeh, Reza, Mohammad Gheshlagi, Rahele Tahmasebi i Farnaz Hojjati. "Spectrophotometric study of interaction and solubilization of procaine hydrochloride in micellar systems". Open Chemistry 7, nr 1 (1.03.2009): 90–95. http://dx.doi.org/10.2478/s11532-008-0078-4.
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AbstractThe interaction of Procaine hydrochloride (PC) with cationic, anionic and non-ionic surfactants; cetyltrimethylammonium bromide (CTAB), sodium dodecyl sulfate (SDS) and triton X-100, were investigated. The effect of ionic and non-ionic micelles on solubilization of Procaine in aqueous micellar solution of SDS, CTAB and triton X-100 were studied at pH 6.8 and 29°C using absorption spectrophotometry. By using pseudo-phase model, the partition coefficient between the bulk water and micelles, Kx, was calculated. The results showed that the micelles of CTAB enhanced the solubility of Procaine higher than SDS micelles (Kx = 96 and 166 for SDS and CTAB micelles, respectively) but triton X-100 did not enhanced the solubility of drug because of weak interaction with Procaine. From the resulting binding constant for Procaine-ionic surfactants interactions (Kb = 175 and 128 for SDS and CTAB surfactants, respectively), it was concluded that both electrostatic and hydrophobic interactions affect the interaction of surfactants with cationic procaine. Electrostatic interactions have a great role in the binding and consequently distribution of Procaine in micelle/water phases. These interactions for anionic surfactant (SDS) are higher than for cationic surfactant (CTAB). Gibbs free energy of binding and distribution of procaine between the bulk water and studied surfactant micelles were calculated.
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Tazhibayeva, Sagdat, Kuanyshbek Musabekov, Zhenis Kusainova, Ardak Sapieva i Nurlan Musabekov. "Complex Formation of Polyacrylic Acid with Surfactants of Different Hydrophobicity". Applied Mechanics and Materials 752-753 (kwiecień 2015): 212–16. http://dx.doi.org/10.4028/www.scientific.net/amm.752-753.212.
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Complex formation processes of polyelectrolytes with surfactant ions are close model to protein - lipid interactions in living organisms. Furthermore, polymer – surfactant complexes are widely used as stabilizers of industrial dispersions and structurants of soil. When using the polymer-surfactant complexes the hydrophilic-lipophilic balance has the great importance. The interaction of polyacrylic acid with alkylammonium salts of different hydrophobicity: cetyltrimethylammonium bromide, dilaurildimethylammonium bromide and dioctadecyldimethylammonium chloride was studied by potentiometry, spectrophotometry, viscometry and electrophoresis methods. It was established that the complex formation of polyacrylic acid with cationic surfactants is carried out due to the electrostatic interaction between carboxyl groups of the polymer and cations of surfactants, which stabilized by hydrophobic interactions between their non-polar parts. The phenomenon of hysteresis in the change of the reduced viscosity of system surfactant /polyacrylic acid with temperature variation in the range of 20-60 °C was found. The possibility of using the complex formation process for water purification from CTAB has been shown. The degree of purification is 99.6-99.8%.
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Reddy, M. C. Somasekhara, S. M. Sarvar Jahan, K. Sridevi i G. V. Subba Reddy. "Investigations on Natural Surfactant obtained from Soap-Nuts through Spectrophotometric Interactions with Congo Red and Comparison with Commercial Surfactants". Asian Journal of Chemistry 31, nr 4 (27.02.2019): 907–16. http://dx.doi.org/10.14233/ajchem.2019.21849.
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A natural surfactant (NS) of plant-base was obtained from the fruit pericarp of soapnuts by using a simple and economical method. The interaction of this natural surfactant with direct dye, anionic dye, Congo red (CR) was studied spectrophotometrically in sub-micellar and micelle concentration range in aqueous solution. These interactions (CR-NS) were compared with that of CR-CTAB (cationic surfactant-cetyl trimethylammonium bromide, CTAB), CR-SDS (anionic surfactant-sodium dodecyl sulphate, SDS) and CR-TX 100 (neutral surfactant - Triton X-100, TX 100) and were useful to understand the nature of natural surfactant. The mechanism of formation of complex due to interactions between Congo red and natural surfactant was suggested. This spectrophotometric method was used for the determination of critical micelle concentration (CMC), at which the formation of micelles was started. The CMC values obtained spectrophotometrically for the natural surfactant was coincided with the experimental value available in the literature. A definite change in the absorbance maxima of Congo red in the presence of natural surfactant (micelles of natural surfactant) was also observed. The change in maxima was also interpreted in terms of pH and CMC. The equilibrium constant of interaction between Congo red and natural surfactant was calculated on the theoretical model. The stability of the complexes of Congo red with different surfactants like CTAB, SDS, TX 100 and natural surfactant may be written in increasing order as: CR-TX 100 > CR-CTAB > CR-NS > CR-SDS. The biodegradable, non-toxic, inexpensive, environmental friendly, renewable natural surfactant was suggested in place of synthetic surfactants.
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Nazarova, Anastasia, Arthur Khannanov, Artur Boldyrev, Luidmila Yakimova i Ivan Stoikov. "Self-Assembling Systems Based on Pillar[5]arenes and Surfactants for Encapsulation of Diagnostic Dye DAPI". International Journal of Molecular Sciences 22, nr 11 (3.06.2021): 6038. http://dx.doi.org/10.3390/ijms22116038.
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In this paper, we report the development of the novel self-assembling systems based on oppositely charged Pillar[5]arenes and surfactants for encapsulation of diagnostic dye DAPI. For this purpose, the aggregation behavior of synthesized macrocycles and surfactants in the presence of Pillar[5]arenes functionalized by carboxy and ammonium terminal groups was studied. It has been demonstrated that by varying the molar ratio in Pillar[5]arene-surfactant systems, it is possible to obtain various types of supramolecular systems: host–guest complexes at equimolar ratio of Pillar[5]arene-surfactant and interpolyelectrolyte complexes (IPECs) are self-assembled materials formed in aqueous medium by two oppositely charged polyelectrolytes (macrocycle and surfactant micelles). It has been suggested that interaction of Pillar[5]arenes with surfactants is predominantly driven by cooperative electrostatic interactions. Synthesized stoichiometric and non-stoichiometric IPECs specifically interact with DAPI. UV-vis, luminescent spectroscopy and molecular docking data show the structural feature of dye-loaded IPEC and key role of the electrostatic, π–π-stacking, cation–π interactions in their formation. Such a strategy for the design of supramolecular Pillar[5]arene-surfactant systems will lead to a synergistic interaction of the two components and will allow specific interaction with the third component (drug or fluorescent tag), which will certainly be in demand in pharmaceuticals and biomedical diagnostics.
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Acharya, Shveta, i Arun Kumar Sharma. "Spectrometric, Thermodynamic, pH Metric and Viscometric Studies on the Binding of TEALS as Surfactant with Albumin as Biopolymer". Current Physical Chemistry 10, nr 1 (29.01.2020): 47–64. http://dx.doi.org/10.2174/1877946809666190913182152.
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Background:: Since the interactions of small anions with protein are very important in their transportation and distribution processes in biological systems, it is helpful to study these interactions to understand the nature of the transportation and distribution processes. Therefore, it is aimed to study the interaction of albumin with surfactant molecule by different physical methods. Objective:: Present work attempts to work on assessing the structure, characterization of the surfactants as TEALS (tri-ethanalamine lauryl sulphate) binding sites, with albumin involved in various process of living being are discussed. Method:: The binding of surfactant TEALS to egg protein has been studied at different pH values and temperatures by spectrophotometric and equilibrium dialysis methods. The binding data were found to be pH and temperature dependent. The binding data studied by the absorbance method, were found approximately identical with those obtained from the equilibrium dialysis method. Results:: The association constants and the number of binding sites were calculated from Scatchard plots and found to be at maximum at lower pH and at lower temperature. The free energy of the combining sites was lowest at higher pH and highest at low pH. Therefore, a lower temperature and a lower pH offered more sites in the protein molecule for interaction with surfactant. The ΔG (free energies of aggregation) associated with the binding interaction of the surfactants and protein were calculated. The negative values of the ΔG confirm the feasibility of interaction between the surfactant and protein. All the observations recorded in this paper indicate that the TEALS has a good affinity of binding with egg protein and the number of binding sites is dependent on various physical and chemical factors. Conclusion:: On the basis of the results of the experiments which were conducted to examine the interaction between anionic surfactant and protein by measuring the various parameters of the solutions, it is concluded that the interaction of surfactant and protein gives an idea of fundamental understanding of the structure of surfactant-protein complex and their practical applications in every field.
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Perron, Gérald, Josée Francoeur, Jacques E. Desnoyers i Jan C. T. Kwak. "Heat capacities and volumes in aqueous polymer and polymer–surfactant solutions". Canadian Journal of Chemistry 65, nr 5 (1.05.1987): 990–95. http://dx.doi.org/10.1139/v87-169.
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The apparent molar volumes and heat capacities of aqueous mixtures of neutral polymers and ionic surfactants were measured at 25 °C. The polymers chosen were poly(vinylpyrrolidone) (PVP) and poly(ethyleneoxide) (PEO) and the surfactants were the C8, C10, and C12 homologs of sodium alkylsulfates and the C10, C12, and C16 homologs of alkyltrimethylammonium bromides. The polymer–surfactant interactions depend on the nature of both components and on the chain length of the surfactant. The thermodynamic properties of the cationic surfactants are essentially the same in the absence and presence of polymer indicating little surfactant–polymer interaction. On the other hand, the thermodynamic properties of anionic surfactants are shifted, upon the addition of polymers, in the direction of enhanced hydrophobic association. The effect increases with the surfactant chain length and with the polymer concentration. The effect is larger with PVP than with PEO.
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Akanno, Andrew, Eduardo Guzmán, Laura Fernández-Peña, Francisco Ortega i Ramón G. Rubio. "Surfactant-Like Behavior for the Adsorption of Mixtures of a Polycation and Two Different Zwitterionic Surfactants at the Water/Vapor Interface". Molecules 24, nr 19 (23.09.2019): 3442. http://dx.doi.org/10.3390/molecules24193442.
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The bulk and interfacial properties of solutions formed by a polycation (i.e., poly(diallyl-dimethylammonium chloride), PDADMAC) and two different zwitterionic surfactants (i.e., coco-betaine (CB) and cocoamidopropyl-betaine (CAPB)) have been studied. The bulk aggregation of the polyelectrolyte and the two surfactants was analyzed by turbidity and electrophoretic mobility measurements, and the adsorption of the solutions at the fluid interface was studied by surface tension and interfacial dilational rheology measurements. Evidence of polymer–surfactant complex formation in bulk was only found when the number of surfactant molecules was closer to the number of charged monomers in solutions, which suggests that the electrostatic repulsion associated with the presence of a positively charged group in the surfactant hinders the association between PDADMAC and the zwitterionic surfactant for concentrations in which there are no micelles in solution. This lack of interaction in bulk is reflected in the absence of an influence of the polyelectrolyte in the interfacial properties of the mixtures, with the behavior being controlled by the presence of surfactant. This work has evidenced the significant importance of the different interactions involved in the system for controlling the interaction and complexation mechanisms of in polyelectrolyte–surfactant mixtures.
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Mohanty, Sagarika, Jublee Jasmine i Suparna Mukherji. "Practical Considerations and Challenges Involved in Surfactant Enhanced Bioremediation of Oil". BioMed Research International 2013 (2013): 1–16. http://dx.doi.org/10.1155/2013/328608.
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Surfactant enhanced bioremediation (SEB) of oil is an approach adopted to overcome the bioavailability constraints encountered in biotransformation of nonaqueous phase liquid (NAPL) pollutants. Fuel oils containn-alkanes and other aliphatic hydrocarbons, monoaromatics, and polynuclear aromatic hydrocarbons (PAHs). Although hydrocarbon degrading cultures are abundant in nature, complete biodegradation of oil is rarely achieved even under favorable environmental conditions due to the structural complexity of oil and culture specificities. Moreover, the interaction among cultures in a consortium, substrate interaction effects during the degradation and ability of specific cultures to alter the bioavailability of oil invariably affect the process. Although SEB has the potential to increase the degradation rate of oil and its constituents, there are numerous challenges in the successful application of this technology. Success is dependent on the choice of appropriate surfactant type and dose since the surfactant-hydrocarbon-microorganism interaction may be unique to each scenario. Surfactants not only enhance the uptake of constituents through micellar solubilization and emulsification but can also alter microbial cell surface characteristics. Moreover, hydrocarbons partitioned in micelles may not be readily bioavailable depending on the microorganism-surfactant interactions. Surfactant toxicity and inherent biodegradability of surfactants may pose additional challenges as discussed in this review.
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Grotberg, J. B., D. Halpern i O. E. Jensen. "Interaction of exogenous and endogenous surfactant: spreading-rate effects". Journal of Applied Physiology 78, nr 2 (1.02.1995): 750–56. http://dx.doi.org/10.1152/jappl.1995.78.2.750.
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The spreading rate of an exogenous surfactant monolayer due to surface tension gradients is examined by using our previously reported theoretical analysis, with particular attention given to the effects of endogenous surfactant. It is found that the presence of an endogenous surfactant reduces the spreading rate of exogenous surfactant and that, in certain circumstances, the spreading may be halted. A recently published paper (F. F. Espinosa, A. H. Shapiro, J. J. Fredberg, and R. D. Kamm. J. Appl. Physiol. 75: 2028–2039, 1993) reaches the opposite conclusion about the effect of endogenous surfactant, i.e., that the presence of an endogenous surfactant increases the spreading rate of the exogenous surfactant. This communication discusses the relevant issues associated with these different results and what the implications may be for surfactant replacement therapy. It is found that the endogenous surfactant, which is ahead of the advancing exogenous surfactant front, undergoes a concentration increase due to surface area compression of the air-liquid interface. Hence the spreading exogenous surfactant can raise surfactant concentrations in regions distal to its own location, and this is a previously unrecognized potential therapeutic mechanism of instilled surfactants. After initial instillations of intratracheal boluses of exogenous surfactant, additional surfactant may better reach the desired target site if delivered by aerosol. Predictions of surfactant and piggy-backed drug-delivery times through the lung are also discussed.
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Bezuglaya, Elena, Nikolay Lyapunov, Valentyn Chebanov i Oleksii Liapunov. "Study of the formation of micelles and their structure by the spin probe method". ScienceRise: Pharmaceutical Science, nr 4 (38) (31.08.2022): 4–18. http://dx.doi.org/10.15587/2519-4852.2022.263054.
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The aim. To study the surfactant solutions depending on the type and concentration of surfactants as well as their interaction with some excipients by spin probe method.
Materials and methods. Solutions of ionic and nonionic surfactants containing 4 spin probes differing in molecular structure and solubility were studied. Electronic paramagnetic resonance (EPR) spectra were obtained and their type and parameters were determined. The critical micelle concentration (CMC) was determined from the surface tension isotherm, and the rheological parameters were studied by rotational viscometry.
Results. The shape of the EPR spectra and the spectral parameters of the spin probes depended on both the surfactant concentration and the molecular structure and solubility of these spin probes. There was a concentration range in which associations with surfactants formed at surfactant concentrations below the CMC. At surfactant concentrations above the CMC and up to 1 %, the structure of the surfactant micelles did not change. In the micelles, the surfactant modelling probes rotated rapidly about the long axis of the molecule and perpendicular to it, while they were fixed in the radial direction. The rotational diffusion of probes dissolved in water was much faster. The micelle cores formed by nonionic surfactant and P338 were more viscous compared to ionic surfactants. Surfactant micelles were anisotropic in viscosity, and different segments of the alkyl chains of surfactant modelling probes had different dynamic properties. The packing of molecules in the micelles was more ordered and compacted at the level of the fifth carbon atom. The interactions between surfactant and probe and between cationic surfactant and disodium edetate were determined from the parameters of the EPR spectra. The relationship between the changes in the parameters of the EPR spectra with increasing temperature, the P338 content in the solutions, and the sol-gel transition was revealed. Solubilization of lipophilic substances by P338 solutions increased due to the interaction of propylene glycol and P338.
Conclusions. The shape and parameters of the EPR spectra in real solutions and micellar solutions of surfactants were different and also depended on the structure and solubility of spin probes. Surfactant micelles were anisotropic in viscosity, and different segments of the alkyl chains of surfactant modelling probes had different dynamic properties. The packing of molecules in the micelles was more ordered and compacted at the level of the fifth carbon atom. The EPR spectra and/or their parameters changed due to the interaction between surfactant and probe, surfactant and other substances, or sol-gel transitions in P338 solutions
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Moater, Elena Irina, Cristiana Radulescu i Ionica Ionita. "The Spectrophotometric and Tensiometric Study of Interaction Between Nonionic Surfactants with Acid Dye". Revista de Chimie 68, nr 5 (15.06.2017): 1010–13. http://dx.doi.org/10.37358/rc.17.5.5600.
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The study of the interaction between nonionic surfactants and acid dyes is very important in clarifying the mechanism of wool dyeing and colors preservation and also for the washing conditions determination. This paper presents the spectrophotometric and tensiometric data of the interaction between the alkyl polyglucosides surfactants class with new synthesized dye, from the class of azoic dyes derived from 3H-aza-1-oxa-2H-tioxo-5,8-fenalendisulfonic acid. A multiplicity of transitions is observed, when the surface tension of aqueous solutions of nonionic surfactant (APG) in the presence of the acid dye, which interacts strongly with nonionic surfactant to from a dye-surfactant complex, is measured at a constant concentration of the dye and plotted as a function of surfactant concentration. The formation of some surfactant- dye complexes was made evident in the different molecular ratios in the submicellar zone compared to the micellar zone of concentration of the surfactant. There au different equilibrium in the system which compete one another over a large scale of surfactant concentration (adsorption, micellization, small complex formation, large complex �mixed micelles formation).
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Zhang, Zhi-guo, i Hong Yin. "Interaction of nonionic surfactant AEO9with ionic surfactants". Journal of Zhejiang University SCIENCE 6B, nr 6 (czerwiec 2005): 597–601. http://dx.doi.org/10.1631/jzus.2005.b0597.
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Abdel-Rahem, Rami A., Sana Niaz, Abdelmnim M. Altwaiq, Muayad Esaifan, Mohammad Bassam Al Bitar i Abeer Al Bawab. "Synergistic interaction between sodium dodecyl benzene sulfonate (SDBS) and N,N-dimethyldodecan-1-amine oxide (DDAO) and their adsorption onto activated charcoal and Jordanian natural clay". Tenside Surfactants Detergents 59, nr 2 (28.02.2022): 144–58. http://dx.doi.org/10.1515/tsd-2021-2395.
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Abstract Solutions of sodium dodecyl benzene sulfonate (SDBS) and N,N-dimethyldodecan-1-amine oxide (DDAO) with mole fractions of 0.00, 0.25, 0.50, 0.75 and 1.00 were prepared and their surface tension was measured as a function of total surfactant concentration. The critical micelle concentration (CMC) values of these mixed solutions were also determined. The minimum area occupied by a surfactant molecule at air/water interface was calculated for single and binary surfactant mixtures. A pronounced synergistic interaction between SDBS and DDAO was detected. The surface tension and CMC-values of SDBS/DDAO mixtures are significantly lower than those of the single surfactant. The mixed system of SDBS/DDAO exhibits a highly negative interaction parameter (β = −10.6) according to regular solution model, and is found to fulfill the condition of Hua and Rosen, indicting a strong synergistic interaction between the two surfactants. The contact angle measurements show the wettability of the surfactant mixture onto polyethylene substrate is higher than of the respective single surfactant. In addition, the adsorption of SDBS and DDAO or their mixtures on 1.0% activated carbon and 5.0% Jordanian natural clay (JNC), respectively, was investigated using the depletion method. The individual surfactants were found to adsorb to a considerable extent on activated carbon, and a slightly higher adsorption tendency was even measured for mixed SDBS/DDAO surfactant systems. Although no SDBS molecules adsorbed on JNC, adsorption was observed for solutions containing DDAO and SDBS/DDAO surfactants. The improvement in wettability and adsorption of SDBS/DDAO surfactants at the air/water and solid/water interfaces is directly related to the synergistic interaction between the two surfactants.
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Oszwałdowski, Sławomir, Katarzyna Zawistowska, Laura Grigsby i Kenneth Roberts. "Capillary electrophoretic separation and characterizations of CdSe quantum dots". Open Chemistry 8, nr 4 (1.08.2010): 806–19. http://dx.doi.org/10.2478/s11532-010-0052-9.
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AbstractWe have developed a capillary electrophoresis method to characterize the QD surface ligand interactions with various surfactant systems. The method was demonstrated with 2–5 nm CdSe nanoparticles surface-passivated with trioctylphosphine oxide (TOPO). Water solubility was accomplished by surfactant-assisted phase transfer via an oil-in-water microemulsion using either cationic, anionic, or non-ionic surfactants. Interaction between the QD surface ligand (TOPO) and the alkyl chain of the surfactant molecule produces a complex and dynamic surface coating that can be characterized through manipulation of CE separation buffer composition and capillary surface modification. Additional characterization of the QD surface ligand interactions with surfactants was accomplished by UV-VIS spectroscopy, photoluminescence, and TEM. It is anticipated that studies such as these will elucidate the dynamics of QD surface ligand modifications for use in sensors.
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Azum, Naved, Malik Abdul Rub, Anish Khan, Maha M. Alotaibi, Abdullah M. Asiri i Mohammed M. Rahman. "Mixed Micellization, Thermodynamic and Adsorption Behavior of Tetracaine Hydrochloride in the Presence of Cationic Gemini/Conventional Surfactants". Gels 8, nr 2 (17.02.2022): 128. http://dx.doi.org/10.3390/gels8020128.
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In this approach, tensiometry and UV-visible techniques are used to determine the effect of cationic gemini and conventional surfactants on tetracaine hydrochloride (TCH), an anesthetic drug. We have estimated micellar, interfacial, and energetic constraints. To gain a deep understanding of their mixed association behavior, the outputs were examined using different theoretical models. The critical micelle concentration for single and mixed amphiphiles was estimated. The cmc values of mixed amphiphiles were found between the individual amphiphiles due to strong attractive interaction (synergism) between the components after mixing. The non-ideal behavior of mixtures was confirmed by the larger values of ideal cmc than the experimental cmc values. The negative values of interaction parameter (β) and values of activity coefficients less than unity indicate strong synergistic interaction between drug and surfactant. The stability of the mixed systems is demonstrated by the negative Gibbs free energy of micellization and excess free energy of micellization. In contrast to a single chain surfactant, a double chain surfactant (gemini) exhibits better interactions with the drug. Spectral measurements (UV-visible spectra) were used to monitor the binding of the drug with surfactant (conventional as well as gemini). Studying these mixed aggregates could help to optimize their compositions and find synergistic properties between TCH monomers and surfactants.
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Ghosh, Soumen, Arpan Mal, Tanushree Chakraborty, Gobinda Chandra De i Daniel Gerrard Marangoni. "Interaction of a Cationic Surfactant with an Oppositely Charged Polymer". Journal of Surface Science and Technology 32, nr 3-4 (5.04.2017): 107. http://dx.doi.org/10.18311/jsst/2016/14746.
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The interactions between the cationic surfactant Dodecyltrimethylammonium Bromide (DTAB) and anionic polymer sodium carboxymethyl cellulose (Na-CMC) in aqueous medium were studied at 300K over different concentrations of Na-CMC by tensiometry, conductometry, viscometry, turbidimetry and fluorimetry. Aggregation of surfactant was attained in two steps, the first being the monomeric adsorption of surfactants on anionic sites of the polymer saturating at lower concentrations of surfactant and the second one being the formation of micelles by surfactants at higher concentrations. Mainly, two types of interactions prevailed throughout namely, electrostatic and hydrophobic interactions. Due to the variation of the interactions depending on the concentrations of polymer, there has been considerable differences in the behavioural pattern of the profiles for the lower concentrations of polymer compared to that of the upper ones.
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Seng, Lee Yeh, i Berna Hascakir. "Role of Intermolecular Forces on Surfactant-Steam Performance into Heavy Oil Reservoirs". SPE Journal 26, nr 04 (19.05.2021): 2318–23. http://dx.doi.org/10.2118/201513-pa.
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Summary This study investigates the role of polar fractions of heavy oil in the surfactant-steamflooding process. Performance analyses of this process were done by examination of the dipole-dipole and ion-ion interactions between the polar head group of surfactants and the charged polar fraction of crude oil, namely, asphaltenes. Surfactants are designed to reduce the interfacial tension (IFT) between two immiscible fluids (such as oil and water) and effectively used for oil recovery. They reduce the IFT by aligning themselves at the interface of these two immiscible fluids; this way, their polar head group can stay in water and nonpolar tail can stay in the oil phase. However, in heavy oil, the crude oil itself has a high number of polar components (mainly asphaltenes). Moreover, the polar head group in surfactants is charged, and the asphaltene fraction of crude oils carries reservoir rock components with charges. The impact of these intermolecular forces on the surfactant-steam process performance was investigated with 10 coreflood experiments on an extraheavy crude oil. Nine surfactants (three anionic, three cationic, and three nonionic surfactants) were tested. Results of each coreflood test were analyzed through cumulative oil recovery and residual oil content. The performance differences were evaluated by polarity determination through dielectric constant measurements and by ionic charges through zeta potential measurements on asphaltene fractions of produced oil and residual oil samples. The differences in each group of surfactants tested in this study are the tail length. Results indicate that a longer hydrocarbon tail yielded higher cumulative oil recovery. Based on the charge groups present in the polar head of anionic surfactants resulted in higher oil recovery. Further examinations on asphaltenes from produced and residual oils show that the dielectric constants of asphaltenes originated from the produced oil, giving higher polarity for surfactant-steam experiments conducted with longer tail length, which provide information on the polarity of asphaltenes. The ion-ion interaction between produced oil asphaltenes and surfactant head groups were determined through zeta potential measurements. For the most successful surfactant-steam processes, these results showed that the changes on asphaltene surface charges were becoming lower with the increase in oil recovery, which indicates that once asphaltenes are interacting more with the polar head of surfactants, then the recovery rate increases. Our study shows that the surfactant-steamflooding performance in heavy oil reservoirs is controlled by the interaction between asphaltenes and the polar head group of surfactants. Accordingly, the main mechanism that controls the effectiveness of the process is the ion-ion interaction between the charges in asphaltene surfaces and the polar head group of crude oils. Because crude oils carry mostly negatively charged reservoir rock particles, our study suggests the use of anionic surfactants for the extraction of heavy oils.
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Friedl, Julian David, Christian Steinbring, Sergey Zaichik, Nguyet-Minh Nguyen Le i Andreas Bernkop-Schnürch. "Cellular uptake of self-emulsifying drug-delivery systems: polyethylene glycol versus polyglycerol surface". Nanomedicine 15, nr 19 (sierpień 2020): 1829–41. http://dx.doi.org/10.2217/nnm-2020-0127.
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Aim: Comparison of the impact of polyethylene glycol (PEG) and polyglycerol (PG) surface decoration on self-emulsifying drug delivery system (SEDDS)-membrane interaction and cellular uptake. Materials & methods: PEG-, PEG/PG- and PG-SEDDS were assessed regarding their self-emulsifying properties, surface charge, bile salt fusibility, cellular uptake and interaction with endosome-mimicking membranes. Results: SEDDS exhibited droplet sizes between 150 and 175 nm, a narrow size distribution and self-emulsified within 7 min. Higher PEG-surfactant amounts in SEDDS resulted in charge-shielding and thus in a decrease of ζ potential up to Δ11 mV. The inert PEG-surface hampered bile salt fusion and interfered SEDDS–cell interaction. By reducing the PEG-surfactant amount to 10%, cellular uptake increased twofold compared with PEG-SEDDS containing 40% PEG-surfactant. PG-SEDDS containing no PEG-surfactants showed a threefold increased cellular uptake. Furthermore, complete replacement of PEG-surfactants by PG-surfactants led to enhanced cellular interaction and improved disruption endosome-like membranes. Conclusion: PG-surfactants demonstrated high potential to address PEG-surface associated drawbacks in SEDDS.
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Harrison, S. Kent, i Sandra M. Thomas. "Interaction of Surfactants and Reaction Media on Photolysis of Chlorimuron and Metsulfuron". Weed Science 38, nr 6 (listopad 1990): 620–24. http://dx.doi.org/10.1017/s0043174500051596.
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Laboratory experiments were conducted to determine the effects of nonionic surfactants and reaction media (water, glass, and corn leaf residue) on photolysis and subsequent phytotoxicity of chlorimuron and metsulfuron residues. Oxysorbic and octoxynol enhanced rates of chlorimuron and metsulfuron photolysis in aqueous solution and on glass slides compared to controls with no surfactant. Enhanced photolysis of chlorimuron by surfactants was greatest on glass, where 93 and 89% loss occurred after 48 h exposure to ultraviolet light in the presence of oxysorbic and octoxynol, respectively, compared to 38% loss with no surfactant. Similarly, surfactant-enhanced metsulfuron photolysis was greatest on glass with 37 and 67% loss after 48 h exposure in the presence of oxysorbic and octoxynol, respectively, compared to 9% loss with no surfactant. Photolysis of herbicides deposited on corn leaf residue was significantly slower than that on glass or in aqueous media at all exposure times and metsulfuron photolysis on corn residue was enhanced by surfactants only after 144 h exposure. Bioassays confirmed that phytotoxicity of photolyzed herbicide residues was negatively correlated (r=-0.94 for chlorimuron and r=-0.92 for metsulfuron) with loss of parent herbicide as measured by liquid chromatography.
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Song, Yongbo, Yulan Niu, Hongyan Zheng i Ying Yao. "Interaction of Bis-Guanidinium Acetates Surfactants with Bovine Serum Albumin Evaluated by Spectroscopy". Tenside Surfactants Detergents 58, nr 3 (1.05.2021): 187–94. http://dx.doi.org/10.1515/tsd-2020-2283.
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Abstract The interactions between cocopropane bis-guanidinium acetates, tallowpropane bis-guanidinium acetates with bovine serum albumin (BSA) in an aqueous solution were studied by fluorescence and circular dichroic spectroscopy measurements. The aim of the study was to elucidate the influence of the hydrophilic group and the length of the hydrophobic chain of these surfactants on the mechanism of binding to BSA. The results revealed that for both surfactants, at low concentrations, the Stern–Volmer plots had an upward curvature and at high concentrations, the quenching efficiency was decreased with increase in surfactant concentration. Different thermodynamics parameters demonstrated the existence of hydrogen bond and van der Waals force which acting as binding forces. Static quenching was observed among the protein and surfactant. The conformation of BSA was changed at higher surfactant concentrations as shown by synchronous fluorescence and CD spectroscopy. This work reveals the mechanism and binding characteristics between guanidine surfactants and protein, and provided the basis for further applications of surfactants.
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Uznanski, P., J. Pecherz i M. Kryszewski. "Photophysical studies of hydrophobically functionalized polyionene systems in aqueous solutions". Canadian Journal of Chemistry 73, nr 11 (1.11.1995): 2041–46. http://dx.doi.org/10.1139/v95-252.
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Complexes of polyionene and anionic dyes and surfactant were prepared by exchange reaction of counterions in the parent polymer. Fluorescence studies were conducted to observe some characteristic behaviour of these complexes in water Polyionenes with aromatic hydrocarbons adopt an open conformation and there is no evidence for interpolymer interactions. On the contrary, polyionenes with long aliphatic counterions easily form microdomains in aqueous solution due to hydrophobic interaction as evidenced by an increase in excimer emission. Microdomains have an interpolymer nature, as confirmed by measurements of energy transfer from naphthalene to pyrene moieties. Polyionenes with SDS counterions interact with external surfactant molecules and form polymer–surfactant aggregates. Electrostatic repulsions between aggregates dominate on hydrophobic interaction between polymer chains and are responsible for conformational changes. Keywords: hydrophobically modified polymers, surfactants, complexation, fluorescence, nonradiative energy transfer
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Opanasenko, O. N., N. P. Krutko, O. L. Zhigalova, O. V. Luksha i T. A. Kozinets. "Adsorption capacity of binary surfactants mixtures at solution/air and solution/mineral material interfaces". Proceedings of the National Academy of Sciences of Belarus, Chemical Series 54, nr 4 (12.01.2019): 399–405. http://dx.doi.org/10.29235/1561-8331-2018-54-4-399-405.
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The adsorption capacity on the interphase surfaces of solution / air and solution / mineral material of binary mixtures of anionic (alkylbenzenesulfonic acid and its sodium salt (ABSCNa)) and nonionic surfactants (Tween-80) was studied. It has been established that the adsorption interaction of binary mixtures of surfactants with the surface of quartz and dolomite is affected by the presence of potential-determining ions that activate the surface of mineral materials, the charge and hydration of the anionic antagonists, the nature of the intermolecular interactions between the surfactant-components of the mixture. It was shown that the ABSCNa / Tween-80 mixture, characterized by low adsorption capacity to the mineral materials under study and absence of interaction between the surfactant components of the mixture, has a maximum oil displacement capacity from the surface of dolomite and quartz.
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Klovak, Viktoriia, Sergey Kulichenko i Serhii Lelyushok. "Matching Effects in the Interaction of Ionic Surfactants with Fluorescent Reagents in Micellar Solutions of Triton X-100". Methods and Objects of Chemical Analysis 16, nr 3 (2021): 117–26. http://dx.doi.org/10.17721/moca.2021.117-126.
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The influence of cationic and anionic surfactant solutions on the character of the fluorescence spectra of reagents of different charge and hydrophobicity in aqueous solutions of nonionic surfactant Triton X-100 has been studied. An increase in the fluorescence intensity and a shift in the position of the fluorescence maximum with increasing hydrophobicity of reagents and ionic surfactants have been shown. The analytical signal of the surfactant is further amplified in the proximity of the charge values of the reagent and the counterion of the surfactant. The non-monotonic nature of the hydrophobicity effect of cationic surfactants on their analytical signal in the system has been shown. The observed effects are explained by the realization of charge and hydrophobic matching in the interaction of surfactants with the fluorescent reagents. The obtained effects are significant in the design of fluorescent systems for the determination and study of surfactant micelles. Conditions for detecting the content of cetylpyridinium chloride by reaction with eosin Y and sodium tetradecyl sulfate by reaction with rhodamine 6G in the presence of Triton X-100 were proposed. The methods have been tested in detecting the content of the ionic surfactants in pharmaceuticals.
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Walters, Russel M., Guangru Mao, Euen T. Gunn i Sidney Hornby. "Cleansing Formulations That Respect Skin Barrier Integrity". Dermatology Research and Practice 2012 (2012): 1–9. http://dx.doi.org/10.1155/2012/495917.
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Surfactants in skin cleansers interact with the skin in several manners. In addition to the desired benefit of providing skin hygiene, surfactants also extract skin components during cleansing and remain in the stratum corneum (SC) after rinsing. These side effects disrupt SC structure and degrade its barrier properties. Recent applications of vibrational spectroscopy and two-photon microscopy in skin research have provided molecular-level information to facilitate our understanding of the interaction between skin and surfactant. In the arena of commercial skin cleansers, technologies have been developed to produce cleansers that both cleanse and respect skin barrier. The main approach is to minimize surfactant interaction with skin through altering its solution properties. Recently, hydrophobically modified polymers (HMPs) have been introduced to create skin compatible cleansing systems. At the presence of HMP, surfactants assemble into larger, more stable structures. These structures are less likely to penetrate the skin, thereby resulting in less aggressive cleansers and the integrity of the skin barrier is maintained. In this paper, we reviewed our recent findings on surfactant and SC interactions at molecular level and provided an overview of the HM technology for developing cleansers that respect skin barrier.
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McLachlan, Aleisha A., i D. Gerrard Marangoni. "1D and 2D NMR investigations of the interaction between oppositely charged polymers and surfactants". Canadian Journal of Chemistry 88, nr 2 (luty 2010): 124–34. http://dx.doi.org/10.1139/v09-039.
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Proton chemical shifts and two-dimensional COSY and NOE spectroscopy (NOESY) experiments have been used to examine the interaction of various oppositely charged surfactant and polyelectrolyte systems, namely, the cationic surfactant dodecyltrimethyammonium bromide (DTAB) and a series of alkanediyl-α,ω-bis(alkyldimethylammonium bromide) surfactants (Gem 12-s-12, where s is the length of the methylene spacer group) with the anionic polyelectrolyte poly(styrene sulfonate) or PSS. In all cases, we observe substantial aromatic-solute-induced chemical shifts (ASIS) in the surfactant peaks of the polymer/surfactant complexes versus that of the pure surfactant spectra. In the case of the DTAB/PSS system, the chemical-shift changes as a function of changing ratio of surfactant to polymer are interpreted in terms of structural changes that occur in the complex with increasing polymer concentration. For the Gem 12-s-12/PSS systems, the interaction of these gemini surfactants with the anionic polyelectrolyte, as deduced from the interpretation of the 1H ASIS shifts and the NOESY cross peaks, is dependent on the length of the methylene spacer. From the NOESY experiments, we observed significant NOESY cross peaks that correlated well with the expected mechanism of interaction as observed in the literature for the single-tailed surfactant/polymer system. NMR techniques are shown to provide information on the molecular arrangement of these molecules in aqueous solution.
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Zheng, Jiaojiao, Jing Zhang, Fengniu Lu, Yi Du, Ding Cao, Shui Hu, Yang Yang i Zhiqin Yuan. "Visualization of Polymer–Surfactant Interaction by Dual-Emissive Gold Nanocluster Labeling". Biosensors 12, nr 9 (26.08.2022): 686. http://dx.doi.org/10.3390/bios12090686.
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Polymer-surfactant interaction decides the performance of corresponding complexes, making its rapid and intuitionistic visualization important for enhancing the performance of products and/or processing in related fields. In this study, the fluorescence visualization of the interaction between cationic hyperbranched polyethyleneimine and anionic sodium dodecyl sulfonate surfactant was realized by dual-emissive gold nanocluster labeling. The sensing mechanism was due to the interaction-induced polymer conformation change, which regulated the molecular structure and subsequent photoradiation process of the gold nanoclusters. All three inflection points of the interactions between the polymers and the surfactants were obtained by the change in fluorescence emission ratio of the designed dual-emissive gold nanoclusters. Moreover, these inflection points are verified by the hydrodynamic diameter and zeta potential measurements.
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Maikokera, Raymond, i Habauka M. Kwaambwa. "Use of Viscosity to Probe the Interaction of Anionic Surfactants with a Coagulant Protein from Moringa oleifera Seeds". Research Letters in Physical Chemistry 2009 (24.05.2009): 1–5. http://dx.doi.org/10.1155/2009/927329.
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The intrinsic viscosity of the coagulant protein was evaluated from the flow times of the protein solutions through a capillary viscometer, and the results suggested the coagulant protein to be globular. The interactions of the coagulant protein with anionic surfactant sodium dodecyl sulphate (SDS) and sodium dodecyl benzene sulfonate (SDBS) were also investigated by capillary viscometry. We conclude that there is strong protein-surfactant interaction at very low surfactant concentrations, and the behavior of the anionic surfactants in solutions containing coagulant protein is very similar. The viscometry results of protein-SDS system are compared with surface tension, fluorescence, and circular dichroism reported earlier. Combining the results of the four studies, the four approaches seem to confirm the same picture of the coagulant protein-SDS interaction. All the physical quantities when studied as function of surfactant concentration for 0.05% (w/v) protein solution either exhibited a maximum or minimum at a critical SDS concentration.
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Khan, Nasreen, i Blair Brettmann. "Intermolecular Interactions in Polyelectrolyte and Surfactant Complexes in Solution". Polymers 11, nr 1 (31.12.2018): 51. http://dx.doi.org/10.3390/polym11010051.
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Polyelectrolytes are an important class of polymeric materials and are increasingly used in complex industrial formulations. A core use of these materials is in mixtures with surfactants, where a combination of hydrophobic and electrostatic interactions drives unique solution behavior and structure formation. In this review, we apply a molecular level perspective to the broad literature on polyelectrolyte-surfactant complexes, discussing explicitly the hydrophobic and electrostatic interaction contributions to polyelectrolyte surfactant complexes (PESCs), as well as the interplay between the two molecular interaction types. These interactions are sensitive to a variety of solution conditions, such as pH, ionic strength, mixing procedure, charge density, etc. and these parameters can readily be used to control the concentration at which structures form as well as the type of structure in the bulk solution.
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Petrovic, Lidija, Jelena Milinkovic, Jadranka Fraj, Sandra Bucko i Jaroslav Katona. "An investigation of chitosan and sodium dodecyl sulfate interactions in acetic media". Journal of the Serbian Chemical Society 81, nr 5 (2016): 575–87. http://dx.doi.org/10.2298/jsc151119024p.
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Polymer/surfactant association is a cooperative phenomenon where surfactant binds to the polymer in the form of aggregates, usually through electrostatic or hydrophobic forces. As already known, polyelectrolytes may interact with oppositely charged surfactants through electrostatic attraction that results in polymer/surfactant complex formation. This behavior could be desirable in wide range of application of polymer/surfactant mixtures, such as improving colloid stability, gelling, emulsification and microencapsulation. In the present study surface tension, turbidity, viscosity and electrophoretic mobility measurements were used to investigate interactions of cationic polyelectrolyte chitosan (Ch) and oppositely charged anionic surfactant, sodium dodecyl sulfate (SDS), in buffered water. Obtained results show the presence of interactions that lead to Ch/SDS complexes formation at all investigated pH and for all investigated polymer concentrations. Mechanisms of interaction, as well as characteristics of formed Ch/SDS complexes, are highly dependent on their mass ratio in the mixtures, while pH has no significant influence.
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Khan, Iftheker A., Joseph R. V. Flora, A. R. M. Nabiul Afrooz, Nirupam Aich, P. Ariette Schierz, P. Lee Ferguson, Tara Sabo-Attwood i Navid B. Saleh. "Change in chirality of semiconducting single-walled carbon nanotubes can overcome anionic surfactant stabilisation: a systematic study of aggregation kinetics". Environmental Chemistry 12, nr 6 (2015): 652. http://dx.doi.org/10.1071/en14176.
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Environmental context Chirally enriched semiconducting single-walled carbon nanotubes (SWNTs) are some of the most utilised nanomaterials. Although chirality of SWNTs is known to influence their electronic properties and interfacial interaction, the interplay between chirality and surfactant structure in SWNT stability is not well understood. This study investigates these interactions, providing data to better assess the environmental fate of SWNTs. Abstract Single-walled carbon nanotubes’ (SWNT) effectiveness in applications is enhanced by debundling or stabilisation. Anionic surfactants are known to effectively stabilise SWNTs. However, the role of specific chirality on surfactant-stabilised SWNT aggregation has not been studied to date. The aggregation behaviour of chirally enriched (6,5) and (7,6) semiconducting SWNTs, functionalised with three anionic surfactants – sodium dodecyl sulfate, sodium dodecyl benzene sulfonate and sodium deoxycholate – was evaluated with time-resolved dynamic light scattering. A wide range of mono- (NaCl) and divalent (CaCl2) electrolytes as well as a 2.5mg total organic carbon (TOC) L–1 Suwannee River humic acid were used as background chemistry. Overall, sodium dodecyl benzene sulfonate showed the most effectiveness in stabilising SWNTs, followed by sodium deoxycholate and sodium dodecyl sulfate. However, the larger diameter (7,6) chirality tubes (compared to (6,5) diameter), compromised the surfactant stability due to enhanced van der Waals interaction. The presence of divalent electrolytes overshadowed the chirality effects and resulted in similar aggregation behaviour for both the SWNT samples. Molecular modelling results elucidated key differences in surfactant conformation on SWNT surfaces and identified interaction energy changes between the two chiralities to delineate aggregation mechanisms. The stability of SWNTs increased in the presence of Suwannee River humic acid under 10mM monovalent and mixed-electrolyte conditions. The results suggest that change in chirality can overcome surfactant stabilisation of semiconducting SWNTs. SWNT stability can also be strongly influenced by the anionic surfactant structure.
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Chandravanshi, Shalini, i Santosh K. Upadhyay. "Interaction of Natural Dye (Allium cepa) with Ionic Surfactants". Journal of Chemistry 2013 (2013): 1–6. http://dx.doi.org/10.1155/2013/685679.
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Allium cepais a natural dye that has been extracted from onion skin with the help of soxhlet apparatus. The pigment in the dye pelargonidin was found to be 2.25%. The interaction of the dye with ionic surfactants, namely, cationic surfactant (cetyltrimethylammonium bromide) and anionic (sodium lauryl sulphate) has been studied by spectrophotometrically, conductivity, and surface tension measurements. The thermodynamic and surface parameters have been evaluated for the interaction process. The results indicate{surfactant-dye}complex formation and domination of adsorption in comparison to micellization.
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Liu, Jianfei, Yuru Wang i Huifang Li. "Synergistic Solubilization of Phenanthrene by Mixed Micelles Composed of Biosurfactants and a Conventional Non-Ionic Surfactant". Molecules 25, nr 18 (21.09.2020): 4327. http://dx.doi.org/10.3390/molecules25184327.
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This study investigated the solubilization capabilities of rhamnolipids biosurfactant and synthetic surfactant mixtures for the application of a mixed surfactant in surfactant-enhanced remediation. The mass ratios between Triton X-100 and rhamnolipids were set at 1:0, 9:1, 3:1, 1:1, 1:3, and 0:1. The ideal critical micelle concentration values of the Triton X-100/rhamnolipids mixture system were higher than that of the theoretical predicted value suggesting the existence of interactions between the two surfactants. Solubilization capabilities were quantified in term of weight solubilization ratio and micellar-water partition coefficient. The highest value of the weight solubilization ratio was detected in the treatment where only Triton X-100 was used. This ratio decreased with the increase in the mass of rhamnolipids in the mixed surfactant systems. The parameters of the interaction between surfactants and the micellar mole fraction in the mixed system have been determined. The factors that influence phenanthrene solubilization, such as pH, ionic strength, and acetic acid concentration have been discussed in the paper. The aqueous solubility of phenanthrene increased linearly with the total surfactant concentration in all treatments. The mixed rhamnolipids and synthetic surfactants showed synergistic behavior and enhanced the solubilization capabilities of the mixture, which would extend the rhamnolipids application.
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Singh, Himanshi, Sugam Kumar i Vinod K. Aswal. "Interplay of interactions in nanoparticle–surfactant complexes in aqueous salt solution". Journal of Applied Physics 132, nr 22 (14.12.2022): 224701. http://dx.doi.org/10.1063/5.0118615.
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The evolution of phase behavior and interactions in anionic silica nanoparticles (Ludox HS40), surfactants [non-ionic decaethylene glycol mono-dodecyl ether (C12E10) and anionic sodium dodecyl sulfate (SDS)], and nanoparticle–surfactant solutions in the presence of salt (NaCl) has been studied using small-angle neutron scattering and dynamic light scattering. In an anionic silica nanoparticle solution (1 wt. %), the phase behavior is controlled by salt concentrations (0–1 M) through screening electrostatic interactions. In the case of 1 wt. % surfactant solutions, the anionic SDS surfactant micelles show significant growth upon adding salt, whereas non-ionic surfactant C12E10 micelles remain spherical until a high salt concentration (1 M). In the mixed system of HS40–C12E10, a transition from a highly stable transparent phase to a two-phase turbid system is observed with a small amount of salt addition CS* (∼0.06 M). The single transparent phase of this system corresponds to sterically stabilized micelles-decorated nanoparticles. For the turbid phase, the results are understood in terms of depletion attraction induced by non-adsorption of C12E10 micelles, which explains the appearance of turbidity at a much lower concentration of salt. In the mixed system of similarly charged nanoparticles and micelles (HS40-SDS), the phase behavior is governed by no physical interaction between the components, and salt screens the repulsive interaction among nanoparticles. These results are further utilized to tune multicomponent interactions and phase behavior of nanoparticles with a mixed C12E10-SDS surfactant system in the presence of salt. The mixed surfactants provide tuning of nanoparticle–micelle as well as micelle–micelle interactions to dictate the phase behavior of a nanoparticle–surfactant solution. In these systems, the effective potential can be described by double-Yukawa potential taking account of attractive and repulsive parts at low and intermediate salt concentrations (<CS*). At high salt concentrations (>CS*), the aggregation of nanoparticles is characterized by fractal aggregates.
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Moater, Irina, Mihaela Olteanu, Otilia Cinteza, Cristiana Radulescu i Ionica Ionita. "Adsorption of Some Alkyloxyethylene Pyridinium Chlorides at Solid-Water Interface". Revista de Chimie 59, nr 2 (9.03.2008): 168–72. http://dx.doi.org/10.37358/rc.08.2.1727.
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The adsorption of cetylalkyl pyridinium and alkyloxyethylene pyridinium chlorides at the silica-alumina water interface at ph =7 and 25 0C was analyzed to determine the type of interaction between surfactant molecules and solid substrat between adsorbed adiacent molecules and with the surfactant molecules in the equilibrium water solution. The experimental adsorption isotherm for the entire concentration range consists of four regions with the maximum adsorption attained at the critical micelle concentration of each surfactant in aqueous solutions. Different models and equations of adsorption suitable to describe different types of forces implicated in adsorption of cationic surfactant at the opposite charged solid surfaces were applied. The free energy of adsorption, free energy of hydrophobic interaction and mean surface aggregation number were calculated. Insertion of oxyethylene groups leads to the increase of the hydrophobicity of these cationic surfactants. From the calculated free energy of adsorption through electrostatic and van der Waals interactions different surface structures were attributed to each region: neutralization of electrical charges, formation of hemimicelles, admicelles and bilayers.
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Moreno-Velarde, Francisco, Elisa I. Martín, José Hidalgo Toledo i Antonio Sánchez-Coronilla. "DFT Study on the Enhancement of Isobaric Specific Heat of GaN and InN Nanosheets for Use as Nanofluids in Solar Energy Plants". Materials 16, nr 3 (18.01.2023): 915. http://dx.doi.org/10.3390/ma16030915.
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In this work, GaN and InN nanosheets with dodecylamine (DDA) as surfactant have been studied as nanofluids to be used in solar plants. The interactions between the sheets and the surfactants have been performed using density functional theory. The most favorable interaction site on the surface corresponds to the metallic atom of the sheet with the N atom of the surfactant. In this interaction, the pair of electrons of N from the surfactant with the metal atom of the sheet play a stabilizing role, which is corroborated by electron localization function (ELF), quantum theory of atoms in molecules (QTAIM), and density of states (DOS) analysis. The isobaric specific heat values for the most favorable interaction were obtained in the presence of water, ethylene glycol, and diphenyl oxide as solvents for the first time. The highest value corresponds to systems with diphenyl oxide, being the values obtained of 0.644 J/gK and 0.363 J/gK for GaN-DDA and InN-DDA systems, respectively. These results open the possibilities of using GaN-DDA and InN-DDA systems in solar energy applications.
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Journal, Baghdad Science. "Synergistic Interaction in the adsorbed mixed surfactants film of Sodium Dodecyl Sulfate and Cocamidopropyl Betaine on Liquid – Air Interfacial". Baghdad Science Journal 13, nr 2 (5.06.2016): 1–9. http://dx.doi.org/10.21123/bsj.13.2.1-9.
Pełny tekst źródłaStreszczenie:
In the present work, the critical micelle concentration (CMC) of the solution of Sodium dodecyl sulfate (SDS) as anionic surfactant, Cocamidopropyl Betaine (CAPB) as amphoteric surfactant, and their mixture have been determined using surface tension and conductivity measurements at a temperature range 293 -323 K. The adsorption and thermodynamic micellization parameters (?G?m, ?G?ads, ?max ,Amin,?cmc ) for individual surfactants was calculated. Rosen model which is focuses on the adsorbed mixed surfactant film at the air/solution interface was used to calculate the interaction parameter ( ?? ) at the interface and the activity coefficients g1 and g2. The results indicate that the CMC of the individual surfactants was affected by the temperature at the temperature range studied. Also, the results indicate a synergistic effect present at the air – solution mixed film of surfactants.
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Zhang, Na, Ruilian Qi, Haofei Li, Bo Guan, Yang Liu, Yuchun Han i Yilin Wang. "Interaction of phospholipid vesicles with gemini surfactants of different lysine spacer lengths". Soft Matter 15, nr 46 (2019): 9458–67. http://dx.doi.org/10.1039/c9sm02040c.
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Akbar, Javed R., Rubena Deubry, D. Gerrard Marangoni i Shawn D. Wettig. "Interactions between gemini and nonionic pharmaceutical surfactants". Canadian Journal of Chemistry 88, nr 12 (grudzień 2010): 1262–70. http://dx.doi.org/10.1139/v10-135.
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The nature and strength of the interactions between the 1,3-bis(dimethylhexadecyl)propanediammonium dibromide (16-3-16) gemini surfactant and a homologous series of nonionic polyoxyethylene (20) sorbitan ester surfactants having laurate (Tween 20), stearate (Tween 60), or oleate (Tween 80) alkyl tails has been investigated. The critical micelle concentration (cmc) values of the mixed gemini–tween systems were determined using the du Noüy ring surface tension method, and the results have been analyzed using Clint’s, Rubingh’s, Motomura’s, and Maeda’s theories for mixed micellar systems. The results demonstrate a synergistic mixing behaviour between the Tween surfactants and the 16-3-16 gemini surfactant, where the strength of interaction is dependent upon the chain length and saturation of the Tween alkyl tail.
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Abdullahi, Wasiu, Martin Crossman i Peter Charles Griffiths. "Surfactant-Modulation of the Cationic-Polymer-Induced Aggregation of Anionic Particulate Dispersions". Polymers 12, nr 2 (1.02.2020): 287. http://dx.doi.org/10.3390/polym12020287.
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Commodity formulations contain many chemically distinct components and their mutual interactions define the beneficial characteristics of the formulation. Mixing oppositely charged polymers and surfactants invariably induces macroscopic phase separation, to a degree dependent on the prevailing polymer and surface charge densities, and the interaction can be modulated by added ionic surfactants. Here, it is shown that a general universality exists between the charge present on a series of cationic-modified cellulose polymers—the charge being controlled either by the degree of cationic modification of the polymer itself or through the subsequent level of anionic surfactant binding—and its capacity to remove anionic colloidal material from solution, be that silica particles or polystyrene-butadiene lattices. Particulate material not removed from solution bears no adsorbed polymer, i.e., the particle surface is bare. Addition of nonionic surfactant does not negate this universality, implying that the nonionic surfactant is largely a spectator molecule or structure (micelle) in these systems, and that the dominant force is an electrostatic one.
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Lu, Run-Chao, Ao-Neng Cao, Lu-Hua Lai i Jin-Xin Xiao. "Protein–surfactant interaction: Differences between fluorinated and hydrogenated surfactants". Colloids and Surfaces B: Biointerfaces 64, nr 1 (czerwiec 2008): 98–103. http://dx.doi.org/10.1016/j.colsurfb.2008.01.009.
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Quanten, Thomas, Pavletta Shestakova, Aleksandar Kondinski i Tatjana Parac-Vogt. "Effect of [Zr(α-PW11O39)2]10− Polyoxometalate on the Self-Assembly of Surfactant Molecules in Water Studied by Fluorescence and DOSY NMR Spectroscopy". Inorganics 6, nr 4 (17.10.2018): 112. http://dx.doi.org/10.3390/inorganics6040112.
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The catalytic fragmentation of hydrophobic proteins by polyoxometalates (POMs) requires the presence of surfactants in order to increase the solubility of the protein. Depending on the nature of the surfactant, different effects on the kinetics of protein hydrolysis are observed. As the molecular interactions between the POMs and surfactants in solutions have been scarcely explored, in this study, the interaction between the catalytically active Keggin polyoxometalate [Zr(α-PW11O39)2]10− and four different surfactants—sodium dodecyl sulfate (SDS), dodecyldimethyl(3-sulfopropyl)ammonium (Zw3-12), dodecyldimethyl(3-sulfopropyl) ammonium (CHAPS), and polyethylene glycol tert-octylphenyl ether (TX-100)—have been studied in aqueous media. The effect of polyoxometalate on the self-assembly of surfactant molecules into micelles and on the critical micellar concentration (CMC) has been examined by fluorescence spectroscopy and diffusion ordered NMR spectroscopy (DOSY).
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Azum, Naved, Malik Abdul Rub, Sulaiman Yahya Alfaifi i Abdullah M. Asiri. "Interaction of Diphenhydramine Hydrochloride with Cationic and Anionic Surfactants: Mixed Micellization and Binding Studies". Polymers 13, nr 8 (9.04.2021): 1214. http://dx.doi.org/10.3390/polym13081214.
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The focus of the present work is to evaluate the interactions of an anti-allergic drug (diphenhydramine hydrochloride, DPH) with anionic (sodium dodecyl sulfate, SDS) and cationic (cetylpyridinium chloride, CPC) surfactants in the aqueous medium. The mixed micellization behavior and surface properties of drug-surfactant mixtures have been examined by surface tension measurements. Various theoretical approaches were applied to explore the synergistic or non-ideal behavior of the current mixed systems. Furthermore, the binding studies of drug with surfactants have been elaborated by UV–visible spectroscopy. Benesi–Hildebrand (B-H) theory was used to compute stoichiometric ratio, binding constant, and free energy change for the drug-surfactant mixtures. The outputs are deliberated taking into consideration the use of surfactants as capable drug delivery agents for DPH and hence advance bioavailability.
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Liu, Qi, Zhitao Chen i Yingzi Yang. "Study of the Air-Entraining Behavior Based on the Interactions between Cement Particles and Selected Cationic, Anionic and Nonionic Surfactants". Materials 13, nr 16 (9.08.2020): 3514. http://dx.doi.org/10.3390/ma13163514.
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The essential role of the air void size distribution in air-entrained cementitious materials is widely accepted. However, how the air-entraining behavior is affected by features such as the molecular structure of air-entraining agents (AEAs), the type of solid particles, or the chemical environment of the pore solution in fresh mortars is still not well understood. Besides, methods to assess the interaction between AEAs and cement particles are limited. Thus, in this study, the air-entraining behaviors of three kinds of surfactant (cationic, anionic, and nonionic) were examined. The general working mechanisms of these surfactants were studied by zeta potential and attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy. Results indicate that the cationic surfactant entrains improper coarse air voids due to the strong electrical interaction between air bubbles formed by the cationic surfactant and negatively charged cement particles. The anionic surfactant interacts with the positively charged part of cement particles, and thus entrains finer air voids. The interaction between the nonionic surfactant and cement particles is very weak; as a result, the nonionic surfactant entrains the finest and homogeneous air voids.
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Parsi, Kurosh. "Interaction of detergent sclerosants with cell membranes". Phlebology: The Journal of Venous Disease 30, nr 5 (14.05.2014): 306–15. http://dx.doi.org/10.1177/0268355514534648.
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Commonly used detergent sclerosants including sodium tetradecyl sulphate (STS) and polidocanol (POL) are clinically used to induce endovascular fibrosis and vessel occlusion. They achieve this by lysing the endothelial lining of target vessels. These agents are surface active (surfactant) molecules that interfere with cell membranes. Surfactants have a striking similarity to the phospholipid molecules of the membrane lipid bilayer. By adsorbing at the cell membrane, surfactants disrupt the normal architecture of the lipid bilayer and reduce the surface tension. The outcome of this interaction is concentration dependent. At high enough concentrations, surfactants solubilise cell membranes resulting in cell lysis. At lower concentrations, these agents can induce a procoagulant negatively charged surface on the external aspect of the cell membrane. The interaction is also influenced by the ionic charge, molecular structure, pH and the chemical nature of the diluent (e.g. saline vs. water). The ionic charge of the surfactant molecule can influence the effect on plasma proteins and the protein contents of cell membranes. STS, an anionic detergent, denatures the tertiary complex of most proteins and in particular the clinically relevant clotting factors. By contrast, POL has no effect on proteins due to its non-ionic structure. These agents therefore exhibit remarkable differences in their interaction with lipid membranes, target cells and circulating proteins with potential implications in a range of clinical applications.