Fourier Transform Rheology as an innovative morphological characterization technique for the emulsion volume average radius and its distribution

• Published in: Journal of colloid and interface science 2012-08, Vol.380 (1), p.201-212
• Main Authors: Reinheimer, K., Grosso, M., Hetzel, F., Kübel, J., Wilhelm, M.
• Format: Article
• Language: English
• Subjects: Chemistry; Colloidal state and disperse state; droplet size; emulsifying properties; Emulsion; emulsions; Emulsions. Microemulsions. Foams; Exact sciences and technology; Fourier Transform Rheology; General and physical chemistry; Polydispersity; rheology; surface tension; viscosity; Volume average radius
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2012.03.079

[Display omitted] ► FT-Rheology characterization of emulsion under nonlinear oscillatory shear. ► Simulations via the Maffettone Minale model in combination with Batchelor theory. ► Nonlinear mechanical master curve determined moment of radii, interfacial tension. ► Application to polydisperse model emulsions and commercial samples. This article extends previous works on emulsion characterization via Fourier Transform Rheology. The interest here is on the effects of (i) polydispersity and (ii) high volume fraction (often associated with commercial samples) on the nonlinear rheological behavior. To analyze the effects of polydispersity on the LAOS measurements, the investigated samples were characterized with respect to their volume average radius, 〈R〉43, and the polydispersity index of the distribution. As the nonlinear mechanical emulsion value E0 introduced in the literature is a function of both nonlinear rheological parameters, such as I5/3, as well as emulsion properties including the volume average radius, interfacial tension and viscosities of the matrix and dispersed phase, it is, therefore, a useful tool for emulsion characterization. In addition, the analysis of the higher harmonic ratios, I7/5, has been demonstrated to provide information about the width of the distribution. With respect to the characterization of the high volume fraction samples, these first experiments on commercial w/o-emulsions were shown to relate nonlinear rheological properties to the droplet size and droplet size distribution of highly filled systems, demonstrating that LAOS experiments can give useful insights on the average droplet size and its distribution.