Coupling of Induction with Damping Behavior for Viscosity Sensing via Design of Magnetized Oscillator

Detection of liquid viscosity is important from chemical engineering to daily safety. To match the emergence of internet of things, precise and fast viscosity determination is attracting intention in the society. However, most miniature viscometers face limitations such as high operation frequency, moving component, and non‐linear sensing, etc. Herein, a flexible viscometer is developed via coupling the electromagnetic induction with inherent oscillation of a magnetized oscillator. The mechanism allows vibration of the oscillator to be electrically reflected using damping signals. By analyzing the damping factor from viscosity‐dependent voltage profiles, viscosity of an unknown liquid can be accurately obtained. Furthermore, the 3D structures is developed with a dual‐template method, which enables convenient and high‐throughput preparations of devices with complex 3D structures. Via optimizing the structural and physical parameters, the “sphere” oscillator enables a linear relationship between the damping factor and the square root of viscosity for quantitative sensing in range of 0.01809–24.7 mPa s. The principle of electromagnetic induction renders the viscometer with superiorities of low operating frequency, remote sensing, self‐powered and chemical stability. It is expected that the methodology and damping dominant mechanism will serve as a promising platform for cost‐effective, portable and convenient viscosity detection for applications in diverse fluids. A viscometer is developed via coupling of the induction and damped oscillation. The optimized sensor can linearly relate electrical signals with viscous parameter in the range of 0.01809–24.7 mPa s.