Effect of Nonionic Surfactants on the Kinetics of Disproportion of Copper Sulfide Nanoparticles in the Aqueous Sols

2001 ◽  
Vol 13 (5) ◽  
pp. 1789-1793 ◽  
Author(s):  
Roshan H. Kore ◽  
Jaideep S. Kulkarni ◽  
Santosh K. Haram
2015 ◽  
Vol 21 (3) ◽  
pp. 429-439 ◽  
Author(s):  
Marija Ilic ◽  
Franz-Hubert Haegel ◽  
Vesna Pavelkic ◽  
Snezana Zlatanovic ◽  
Zoran Markovic ◽  
...  

Microemulsion systems with water, toluene and nonionic surfactants are interesting for application due to the excellent solvent properties of aromatic hydrocarbons. In this study, the pseudo-binary phase diagram (?fish-diagram?) of such a ternary system was investigated using a branched technical alkyl polyethoxylate. Lutensol ON 50 (i-C10E5) was considered a suitable surfactant. The system with technical branched i-C10E5 exhibits very long and for compositions near optimum solubilization, i.e. the minimum content of surfactant needed for a bicontinuous microemulsion, extremely long times for equilibration. In addition to visual observation, qualitative measurements of turbidity were performed with a UV-Vis spectrometer for characterizing the behavior of this unusually sluggish system. Isothermal phase diagrams at 20, 25 and 30?C yielded inconsistent results after the change of temperature and the application of mechanical stress for different treatment of the samples. Ternary mixtures of water, toluene, and Lutensol ON 50 seem to form long-living metastable states. The sluggishness and the ambiguous phase behavior of the system are discussed. Inconsistent results are attributed to the slow kinetics of the formation and destruction of liquid crystals and the ability of the system to form miniemulsions within an unusual concentration range.


2008 ◽  
Vol 42 (4-5) ◽  
pp. 923-930 ◽  
Author(s):  
Ewa Liwarska-Bizukojc ◽  
René Scheumann ◽  
Anja Drews ◽  
Ute Bracklow ◽  
Matthias Kraume

2016 ◽  
Vol 113 (41) ◽  
pp. 11465-11470 ◽  
Author(s):  
Birte Riechers ◽  
Florine Maes ◽  
Elias Akoury ◽  
Benoît Semin ◽  
Philipp Gruner ◽  
...  

Emulsions are metastable dispersions. Their lifetimes are directly related to the dynamics of surfactants. We design a microfluidic method to measure the kinetics of adsorption of surfactants to the droplet interface, a key process involved in foaming, emulsification, and droplet coarsening. The method is based on the pH decay in the droplet as a direct measurement of the adsorption of a carboxylic acid surfactant to the interface. From the kinetic measurement of the bulk equilibration of the pH, we fully determine the adsorption process of the surfactant. The small droplet size and the convection during the droplet flow ensure that the transport of surfactant through the bulk is not limiting the kinetics of adsorption. To validate our measurements, we show that the adsorption process determines the timescale required to stabilize droplets against coalescence, and we show that the interface should be covered at more than 90% to prevent coalescence. We therefore quantitatively link the process of adsorption/desorption, the stabilization of emulsions, and the kinetics of solute partitioning—here through ion exchange—unraveling the timescales governing these processes. Our method can be further generalized to other surfactants, including nonionic surfactants, by making use of fluorophore–surfactant interactions.


2018 ◽  
Vol 24 (2) ◽  
pp. 117-125
Author(s):  
Nebojsa Ristic ◽  
Ivica Dodic ◽  
Ivanka Ristic

The influence of nonionic and anionic surfactants on the dyeing kinetics of polyamide 6 knitting was studied in this work. The influence of surfactants on the dyeing process is presented by determining the kinetic and thermodynamic parameters of dyeing. Nonionic surfactants create unstable polydisperse associates which reduce the concentration of individual ionic forms of dyes in the solution, slowing down the dyeing process, with the dyeing having higher leveling. Interactions were confirmed by measuring the cloud point of nonionic surfactants and they are stronger with more hydrophobic dye and are related to the results of the studied dyeing kinetics. The anionic surfactant as a retarding agent, which behaves like a colorless dye in the studied dyeing system, makes a significant contribution even at concentrations of 0.5 and 1 g/dm3, indicating the conclusion that the surfactant concentration in a dyeing solution should be optimized by previous trials, so that the process would be efficient with high utilization of dye.


1995 ◽  
Vol 26 (1) ◽  
pp. 25-40 ◽  
Author(s):  
A. H. Alyaser ◽  
J. K. Brimacombe

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