386:) of two straight lines traced through plots of the measured property versus the surfactant concentration. This visual data analysis method is highly subjective and can lead to very different CMC values depending on the type of representation, the quality of the data and the chosen interval around the CMC. A preferred method is the fit of the experimental data with a model of the measured property. Fit functions for properties such as electrical conductivity, surface tension, NMR chemical shifts, absorption, self-diffusion coefficients, fluorescence intensity and mean translational diffusion coefficient of fluorescent dyes in surfactant solutions have been presented. These fit functions are based on a model for the concentrations of monomeric and micellised surfactants in solution, which establishes a well-defined analytical definition of the CMC, independent from the technique.
415:
200:
437:(EOR) application. Below the CMC point, interfacial tension between oil and water phase is no longer effectively reduced. If the concentration of the surfactant is kept a little above the CMC, the additional amount covers the dissolution with existing brine in the reservoir. It is desired that the surfactant will work at the lowest interfacial tension (IFT).
406:
When the interfacial areas are large, the amount of surfactant at the interface cannot be neglected. If, for example, air bubbles are introduced into a solution of a surfactant above CMC, these bubbles, as they rise to the surface, remove surfactants from the bulk to the top of the solution creating
393:
is important because surfactants partition between the bulk and interface and CMC is independent of interface and is therefore a characteristic of the surfactant molecule. In most situations, such as surface tension measurements or conductivity measurements, the amount of surfactant at the interface
50:
changes strongly with the concentration of the surfactant. After reaching the CMC, the surface tension remains relatively constant or changes with a lower slope. The value of the CMC for a given dispersant in a given medium depends on temperature, pressure, and (sometimes strongly) on the presence
223:
Subsequently, when the surface coverage by the surfactants increases, the surface free energy (surface tension) decreases and the surfactants start aggregating into micelles, thus again decreasing the system's free energy by decreasing the contact area of hydrophobic parts of the surfactant with
203:
Top to Bottom: Increasing concentration of surfactant in water first leads to the formation of a layer on the surface. After reaching the CMC micelles begin forming. Notice that the existence of micelles does not preclude the existence of individual surfactant molecules in
407:
a foam column and thus reducing the concentration in bulk to below CMC. This is one of the easiest methods to remove surfactants from effluents (see foam flotation). Thus in foams with sufficient interfacial area are devoid of micelles. Similar reasoning holds for
394:
is negligible compared to that in the bulk and CMC can be approximated by the total concentration. In practice, CMC data is usually collected using laboratory instruments which allow the process to be partially automated, for instance by using specialised
723:
Lucas Piñeiro, Sonia Freire, Jorge
Bordello, Mercedes Novo, and Wajih Al-Soufi, Dye Exchange in Micellar Solutions. Quantitative Analysis of Bulk and Single Molecule Fluorescence Titrations. Soft Matter, 2013,9, 10779-10790, DOI:
426:. One initially starts off with concentrations greater than CMC in water and on adding fabric with large interfacial area, the surfactant concentration drops below CMC and no micelles remain at equilibrium. Therefore, the
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Mukerjee, P.; Mysels, K. J. In
Critical Micelle Concentrations of Aqueous Surfactant Systems; NIST National Institute of Standards and Technology: Washington D.C. USA, 1971; Vol. NSRDS-NBS 36
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283:
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669:"A model for monomer and micellar concentrations in surfactant solutions: Application to conductivity, NMR, diffusion, and surface tension data"
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plays a minor role in detergents. Removal of oily soil occurs by modification of the contact angles and release of oil in the form of emulsion.
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water. Upon reaching CMC, any further addition of surfactants will just increase the number of micelles (in the ideal case).
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CMC is most typically measured by plotting surface tension versus surfactant concentration in an automated measurement.
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Upon introducing surfactants (or any surface active materials) into a system, they will initially partition into the
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375:, then the CMC is not related to the method of measurement. On the other hand, when the degree of aggregation is
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According to one well-known definition, CMC is the total concentration of surfactants under the conditions:
814:
766:"A Critical Review on Microbial Enhanced Oil Recovery Using Artificial Sandstone Core: Mathematical Model"
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510:
Dominguez, Ana; Fernandez, Aurora; Gonzalez, Noemi; Iglesias, Emilia; Montenegro, Luis (October 1997).
110:
765:
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Phillips J. The energetics of micelle formation. Transactions of the
Faraday Society 1955;51:561-9
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The CMC is the concentration of surfactants in the bulk at which micelles start forming. The word
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The common procedure to determine the CMC from experimental data is to look for the intersection (
606:"Surfactant-Polymer Coreflood Simulation and Uncertainty Analysis Derived from Laboratory Study"
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in water (without other additives or salts) at 25 °C, atmospheric pressure, is 8x10 mol/L.
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In petroleum industry, CMC is considered prior to injecting surfactant in reservoir regarding
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512:"Determination of Critical Micelle Concentration of Some Surfactants by Three Techniques"
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The CMC is an important characteristic of a surfactant. Before reaching the CMC, the
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lowering the energy of the interface (calculated as area times surface tension), and
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Hakiki, Farizal; Maharsi, Dara Ayuda; Marhaendrajana, Taufan (31 December 2015).
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489:, 2nd ed. (the "Gold Book") (1997). Online corrected version: (2006–) "
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form and all additional surfactants added to the system will form micelles.
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removing the hydrophobic parts of the surfactant from contact with water.
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The CMC generally depends on the method of measuring the samples, since
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Al-Soufi, Wajih; Piñeiro, Lucas; Novo, Mercedes (15 March 2012).
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CMCs and molecular weights of several detergents on OpenWetWare
735:"Concentration-model for surfactants near the cmc | QBFE -USC"
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and concentration of other surface active substances and
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Concentration of surfactants above which micelles form
342:= represents the number of detergent ions per micelle
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610:Journal of Engineering and Technological Sciences
359:depend on the properties of the solution such as
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564:Ullmann's Encyclopedia of Industrial Chemistry
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561:Holmberg, Krister (2019). "Surfactants".
673:Journal of Colloid and Interface Science
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567:. Weinheim: Wiley-VCH. pp. 1–56.
212:, reducing the system free energy by:
181:Pentaethylene glycol monododecyl ether
623:10.5614/j.eng.technol.sci.2015.47.6.9
35:) is defined as the concentration of
772:from the original on 5 November 2022
371:. When the degree of aggregation is
169:Penta(ethyleneglycol)monodecyl ether
158:Penta(ethyleneglycol)monooctyl ether
630:from the original on 20 August 2016
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486:Compendium of Chemical Terminology
146:Hexadecyltrimethylammonium bromide
62:For example, the value of CMC for
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134:Dodecyltrimethylammonium bromide
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123:Decyltrimethylammonium bromide
29:critical micelle concentration
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516:Journal of Chemical Education
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316:are proportionality constants
70:CMCs for common surfactants
57:critical micelle temperature
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55:. Micelles only form above
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685:10.1016/j.jcis.2011.12.037
795:Theory of CMC measurement
111:Sodium tetradecyl sulfate
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402:Practical considerations
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98:Sodium dodecyl sulfate
64:sodium dodecyl sulfate
435:enhanced oil recovery
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278:{\displaystyle \phi }
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248:{\displaystyle \phi }
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367:characteristics, or
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153:cationic surfactant
140:cationic surfactant
129:cationic surfactant
86:Sodium octyl sulfate
815:Colloidal chemistry
188:neutral surfactant
175:neutral surfactant
164:neutral surfactant
118:anionic surfactant
105:anionic surfactant
92:anionic surfactant
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39:above which
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749:18 December
694:10347/17083
361:conductance
347:Measurement
195:Description
37:surfactants
776:5 November
468:References
462:Surfactant
424:detergents
75:Surfactant
703:0021-9797
591:242339510
536:0021-9584
447:Detergent
409:emulsions
273:ϕ
243:ϕ
235:= CMC, (d
210:interface
204:solution.
81:Category
21:colloidal
809:Category
770:Archived
743:Archived
711:22265231
628:Archived
540:Archived
441:See also
185:0.000065
41:micelles
452:Micelle
308:= and
150:0.00092
739:usc.es
709:
701:
634:1 July
589:
579:
546:2 June
534:
338:i.e.,
172:0.0009
161:0.0009
115:0.0021
102:0.0083
27:, the
587:S2CID
481:IUPAC
301:= ,
262:) = 0
137:0.016
126:0.065
778:2022
751:2023
707:PMID
699:ISSN
636:2016
577:ISBN
548:2023
532:ISSN
391:bulk
355:and
330:+ NC
312:and
89:0.13
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689:hdl
681:doi
677:370
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495:doi
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231:if
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314:B
310:A
306:m
303:C
299:s
296:C
292:B
288:A
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257:C
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Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
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