Abstract
On the basis of conventional scaling theory, the two-point scaling theory was modified in order to describe the influence of composition on the partial molar heat capacity and volume during the micellization process. To verify the theory, isobaric heat capacities and densities of aqueous sodium octanoate solutions were measured over wide composition and temperature ranges and the modified approach was used to analyze the calculated partial molar heat capacities and volumes of the surfactant in water. The results obtained indicate that the micellization process is subject to the scaling laws. The results were compared with those for other systems. Peculiar behavior of the critical indices was observed and correlated with the structure of the micelles.Electronic Supplementary MaterialThe online version of this article (doi:10.1007/s10953-012-9795-6) contains supplementary material, which is available to authorized users.
Highlights
Research on colloidal systems is carried out using many different experimental techniques
One of such models is scaling theory [1], the two-point scaling theory introduced by Wojtczak et al [2, 3] for the description of paramagnetic–ferromagnetic phase transitions, which extends the theory to the case of noncontinuous phase transitions
The partial molar heat capacities were calculated according to Eq 32. This procedure was previously used for the determination of partial molar heat capacities of other colloidal systems and satisfactory agreement was found with data available in the literature [4, 5]
Summary
Research on colloidal systems is carried out using many different experimental techniques. Interpreting the experimental data requires a model which combines a description of the thermodynamics together with a description of the structure One of such models is scaling theory [1], the two-point scaling theory introduced by Wojtczak et al [2, 3] for the description of paramagnetic–ferromagnetic phase transitions, which extends the theory to the case of noncontinuous phase transitions. This idea came from the fact that some analogies can be perceived between the phase transitions that occur in the two systems. The similarity between the shape of the curve describing the partial molar heat capacities at constant pressure of surfactant on molality, and the shape of the temperature dependence of the specific heat capacities under the constant external field in the case of magnetic systems, gave us additional encouragement to consider whether phase transitions in these solutions follow scaling laws
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
