Between 20 and 90 MHz frequency-dependent shear viscosities of the polystyrene-cyclohexane mixture of critical composition have been measured at polymer molar weight Mw = 30,000. The viscosity data reveal dispersion, in conformity with relaxation characteristics in the non-critical background contributions to the ultrasonic attenuation, i.e., in the longitudinal viscosity of the critical system. The dispersion behavior is discussed with a view to its effect on the critical dynamics of the liquid near its consolute point. Attention is especially given to the relaxation rates of fluctuations of that system. The data as resulting from ultrasonic attenuation spectroscopy on the one hand and from quasi-elastic light scattering and viscosity measurements on the other hand differ near the critical temperature. It is concluded that likely an additional dispersion exists in the shear viscosity at frequencies below the presently available frequency range of measurement.
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http://dx.doi.org/10.1063/1.4862825 | DOI Listing |
Sci Rep
January 2025
Department of Food Engineering and Technology, Tezpur University, Tezpur, India.
This study explores the impact of natural deep eutectic solvents (NADES) on the structure and functionality of treebean (Parkia timoriana) seed protein, a novel approach to enhancing protein stability and functionality for sustainable bioprocessing. The research aims to evaluate the dynamic interactions between protein and choline chloride-sugar-based NADES, focusing on their effects on thermal properties, emulsification behaviour, and rheological characteristics. NADES were formulated using different sugars, and protein-NADES dispersions were analysed for their physicochemical and functional properties.
View Article and Find Full Text PDFLangmuir
January 2025
Institute of Chemical Technology and Engineering, Faculty of Chemical Technology, Poznan University of Technology, ul. Berdychowo 4, PL 60-965 Poznan, Poland.
Despite extensive research on the use of salts to enhance micellar growth, numerous questions remain regarding the impact of ionic exchange and molecular structure on charge neutralization. This study looks into how certain cations (Na, Ca, and Mg) affect the structure of a cocamidopropyl betaine CAPB and sodium dodecylbenzenesulfonate SDBS surfactant mixture, aiming toward applications in targeted delivery systems. The mixture consists of a zwitterionic surfactant, cocamidopropyl betaine (CAPB), and an anionic surfactant, sodium dodecylbenzenesulfonate (SDBS), combined in varying molar ratios at a total concentration of 200 mM.
View Article and Find Full Text PDFLab Chip
January 2025
Department of Food Science and Technology, Cornell University, Ithaca, NY 14853, USA.
Sperm navigation through the complex microarchitecture of the fallopian tube is essential for successful fertilization. Spatiotemporal structural alteration due to folded epithelium or muscle contractions in the fallopian tube changes the geometry of the sperm pathways. The role of structural complexity in sperm navigational patterns has been investigated for single sperm cells but has not been fully addressed at the population level.
View Article and Find Full Text PDFSoft Matter
January 2025
Department of Chemical and Biological Engineering, Northwestern University, Evanston, IL, 60208, USA.
Lithium-ion battery cathodes are manufactured by coating slurries, liquid suspensions that typically include carbon black (CB), active material, and polymer binder. These slurries have a yield stress and complex rheology due to CB's microstructural response to flow. While optimizing the formulation and processing of slurries is critical to manufacturing defect-free and high-performance cathodes, engineering the shear rheology of cathode slurries remains challenging.
View Article and Find Full Text PDFActive fluids are driven out of thermodynamic equilibrium by internally generated forces, causing complex patterns of motion. Even when both the forces and motion are measurable, it is not yet possible to relate the two, because the sources of energy injection and dissipation are often unclear. Here, we study how energy is transferred by developing a method to measure viscosity from the shear stresses and strain rates within an epithelial cell monolayer.
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