Capacitive micromachined ultrasonic transducer (CMUT) based resonant gas sensor array for portable VOC detection with wireless system

Abstract

The development of portable volatile organic compound (VOC) sensor are essential for home healthcare, workplace security because VOCs are critical environmental pollutant to human health. Here, we report capacitive micromachined ultrasonic transducer (CMUT)-based portable sensor for the multiplex detection of various VOCs (toluene, acetone, ethanol and methanol). Three CMUT devices were functionalized with the layers of (1) peptide, (2) the colloids of single-walled nanotube and peptide, (3) poly(styrene-co-allyl alcohol). Each devices exhibit the different sensitivities to four VOCs and highest sensitivities to toluene and ethanol. Through principal component analysis, the selective detection of all four gases are achieved. For the simultaneous detection of VOCs on CMUT devices, the frequencies from each devices are measured by switching a single oscillator in every XXs. With a wireless system, the measured frequencies are displayed in smart phone and the concentration of VOCs are monitored. It is anticipated that CMUT-based sensor array can be applied as the portable VOC sensor system in workplace monitoring and home healthcare.