Flexible Acetone Gas Sensor based on ZIF-8/Polyacrylonitrile (PAN) Composite Film

ZIF-8 is a Zn-based metal organic framework material which can adsorb acetone gas, so it can be used as the gas sensing material of capacitive acetone sensor. In addition, it can be combined with electrospinning nanofibers to form a fibrous gas sensitive material, so that the acetone sensor using it as the gas sensing material has excellent flexibility and this kind of excellent flexibility cannot be achieved in the research of flexible acetone sensor at present. In this work, ZIF-8/polyacrylonitrile (PAN) nanofiber membrane composite with excellent flexibility was prepared by seed embedding method and secondary growth method. The key to the material preparation process is to prepare 2-methylimidazol/PAN composite membrane firstly by blended electrospinning and use the 2-methylimidazole embedded in the nanofiber membrane as the site for the growth of ZIF-8 on the surface of the nanofiber membrane. Then the metal salts and ligands needed for the growth of ZIF-8 were provided by the secondary growth method in stages and finally the fibrous gas sensitive material ZIF-8/PAN could be obtained. After that, a capacitive acetone sensor using flexible ZIF-8/PAN composite material as flexible gas sensing layer and carbon nanotubes as flexible electrode was prepared. The sensor has excellent flexibility, high porosity and fully exposed active site. Due to these characteristics, the sensor has a sensitive response to acetone gas in the range of 250 similar to 2000 cm(3)/m(3), and the response shows good linearity (R-2=0.99659). In addition, the sensor has good cyclic response, long-term stability, and shows good selectivity for acetone among nine common volatile organic compounds. It is worth noting that due to the excellent flexibility of the fibrous gas sensitive layer ZIF-8/PAN, the response value of the sensor to acetone gas under 180 degrees bending state is almost the same as that to acetone under 0 degrees unbending state, and the sensor also shows a stable response to acetone after 180 degrees bending-recovery within 200 times. Besides these excellent performances in flexibility, the use temperature of the sensor is room temperature. These characteristics make it have the development potential to combine with clothing to form a portable flexible acetone sensor.