A Novel CMUT-Based Resonant Biochemical Sensor Using Electrospinning Technology

In this paper, a novel capacitive micromachined ultrasonic transducer (CMUT)-based resonant biochemical sensor is presented to detect SO₂ with a sensitive polymer layer functionalized by electrospinning technology. The electrospinning technology is proposed as an innovative functionalization method to fabricate nano reticular polymer fibers with the diameters of 50-500 nm on the movable plates of the CMUTs. The surface topography of electrospun nanofibers and the impedance properties of functionalized CMUTs are characterized. The CMUT-based resonant biochemical sensor is packaged to detect SO₂ in the experiments. Its resonant frequency shifts vary against the variation of SO₂ concentration. The influences of the mixed gas flow rate are also analyzed. These show that the proposed sensor has good volume sensitivity and frequency stability.