Determination of Critical Micelle Concentration of Some Surfactants by Three Techniques

Abstract

The laboratory experiments described in this work present the CMC-determination of some surfactants by following three different methods, which require the use of the very common techniques in physical chemistry laboratories, such as UV-Vis spectroscopy, luminescence spectroscopy, and electrical conductivity.In performing these experiments, the CMC of a surfactant is determined by measuring a change (i) in the UV-Vis spectra of benzoylacetone, (ii) in the fluorescence emission spectra of pyrene monomers, and (iii) in the electrical conductivity of an ionic-surfactant solution, as the concentration of the surfactant increases.The CMC values corresponding to the surfactants sodium dodecyl sulfate, tetradecyl trimethylammonium bromide and polyoxyethylene,9-dodecyl ether determined in this work following the three indicated methods and in the absence and presence of electrolytes and non-electrolytes are reported.

An amphipathic polypeptide derived from poly‐γ‐glutamic acid for the stabilization of membrane proteins

“…The CMC of APG was measured using pyrene, an environmentally sensitive fluorescent dye used for the determination of the CMCs of detergents. 15,16 The intensity ratio of emission peaks (I 373 nm / I 384 nm ) of pyrene decreases at APG concentration of 0.001% or higher, and the apparent CMC of APG was estimated to be 3.5 lM or 0.006%, which is 2-3 Figure 1. (A) Synthetic scheme of APG.…”

Improvement of Surfactant Flooding Performance by Application of Nanoparticles in Sandstone Reservoirs

“…Several methods have been reported in literature to obtain CMC 8), 9) , but UV-absorption spectroscopy method, fluorescence spectroscopy method, and electrical conductivity method are common for laboratory measurements 10) . Conductivity measurement method is based on the fact that under normal conditions, an ionic surfactant (below its CMC) is completely dissociated and there is a linear relationship between the molar conductivity of the surfactant solution and its concentration as the surfactant monomers behave as normal electrolytes.…”

A low volume 3D-printed temperature-controllable cuvette for UV visible spectroscopy

“…Using a UV visible method in combination with the dye methylene blue, such that the dye partitions into the interior of micelles changing the concentration of the dye in solution, we determined the CMC of SDS at 40°C to be 7.0 ± 0.3 mM in water, which agrees well with measurements in the literature. Figure S1B shows the results of this analysis, where the CMC is estimated from the graph by considering the gradients of two intersecting lines [20], which correspond to the linear increase in absorbance of the dye as a function of concentration in the presence and absence of micelles. There are a number of reports in the literature where the CMC of different amphiphiles, i.e.…”

“…Figure 2A the thermochromic shift of UV visible spectra for CoCl2 in solutions of water and propan-2-ol. Measurements were made at water bath temperatures of 20, 25, 30, 35, 40, 43 and 45°C, the peak centred at 660 nm increases in size with temperature. Figure 2B dependence of absorption at 660 nm on temperature for CoCl2 solutions in solutions of water and propan-2-ol.…”

“…Figure S1B shows the results of this analysis, where the CMC is estimated from the graph by considering the gradients of two intersecting lines [20], which correspond to the linear increase in absorbance of the dye as a function of concentration in the presence and absence of micelles. There are a number of reports in the literature where the CMC of different amphiphiles, i.e.…”