Publikacja współautorstwa prof. Arkadiusza Józefczaka ukazała się w Measurement Volume 178, June 2021.
Rafał Bielas, Bassam Jameel, Arkadiusz Józefczak, Monitoring of Pickering emulsion stability during magnetic heating using ultrasound measurements.
https://doi.org/10.1016/j.measurement.2021.109431
Abstract:
Magnetic heating of colloidal systems is becoming a more and more common route for inducing temperature rise, especially in applications where very local temperature elevation is desired. Although the calorimetric properties of magnetic colloids are extensively investigated, the influence of the alternating magnetic field on their structure has rarely been reported. Meanwhile, potential permanent structural changes such as the formation of agglomerates can affect the stability of magnetic dispersions or magnetic Pickering emulsions. In the present work, we propose to use ultrasound as a technique to determine if such changes occur during magnetic heating. Oil-in-oil emulsions with magnetite particle shells around the droplets and oil-based magnetic fluids were exposed to alternating magnetic fields, and the changes in ultrasonic attenuation and the speed of ultrasound were determined. Finally, changes in acoustic properties were investigated in dispersions of magnetic and polystyrene particles after heating to the melting temperature of the soft particles.