The Temperature Dependence of the Critical Micelle Concentrations of Foam-Forming Surfactants

✍ Scribed by Elaine N.B. Stasiuk; Laurier L. Schramm

• Publisher: Elsevier Science
• Year: 1996
• Tongue: English
• Weight: 187 KB
• Volume: 178
• Category: Article
• ISSN: 0021-9797
• DOI: 10.1006/jcis.1996.0120

✦ Synopsis

surfactants decreases with increasing temperature to some The critical micelle concentrations (CMCs) were determined minimum value and then increases (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17). The minimum for five commercial surfactants in two brines of different hardness is generally between 0 and 40ЊC, typically at room temperabut equal ionic strength. These included a carboxyl-betaine, a ture, and is unique to each surfactant system.

sulfo-betaine, a mixture of anionics, and its two individual compo-

The CMC-temperature dependence of amphoteric surfacnents. CMCs were measured by three techniques: (i) surface tentants is similar to that of ionics (18-26). These studies have sions by Wilhelmy plate at ambient pressure, from 2 to 30ЊC, (ii) been limited to temperatures below 65ЊC.

surface tensions by captive drop, at 1.38 MPa applied pressure, Pressure studies on the CMC have been made exclusively from 25 to 180ЊC, and (iii) dynamic foam height measurements at 1.38 MPa (applied) from 23 to 180ЊC. The CMCs were found with ionic surfactants (4,(22)(23)(24)(25)(26). The CMC increases with to decrease to a minimum with increasing temperature and then pressure to some maximum value and then decreases. These sharply increase, most markedly over 100ЊC. This behavior is exstudies are largely independent of temperature effects, typiplained in terms of hydrophobic forces, described in terms of calcucally being performed at 25 or 30ЊC, with the exception of lated thermodynamic parameters using the phase separation Kaneshina et al. (25), where the temperature was varied model, and forms the basis for a predictive model of the temperafrom 17 to 40ЊC. ture dependence of the CMC using the reduced-variables ap-Hydrocarbons are sparingly soluble in water and the addiproach.