QCM Sensing the Motion of Magnetic Particles: Principle and Signal Acquisition

The traditional quartz crystal microbalance (QCM) technology is primarily used for measuring load mass and requires the load to be in a static state, making it difficult to capture particle motion under the action of external force fields. This study to overcome the constraints of traditional QCM technology by proposing the use of QCM to detect particle motion in liquid loads. This work delves into the principle of QCM sensing particle motion in liquid loads and presents sensing signal models. By investigating the motion mechanism of magnetic particles driven by a magnetic field and generating controllable particle motion, the modulation effect of particle motion on QCM vibration is demonstrated. Experimental results show that particle motion influences the surface strain of the QCM through the liquid medium, modulating the thickness-shear vibration of the QCM. Consequently, particle motion signals can be obtained from the QCM output. Compared to traditional QCM methods that detect static loads, sensing particle motion enables higher sensitivity and stability in detecting parameters (including mass) and allows for the simultaneous detection of multiple load parameters. This study aims to overcome the limitations of traditional QCM technology by proposing a novel approach for detecting particle motion, not only enabling the simultaneous detection of multiple characteristics of the load but also significantly improving detection performance.