A miniature chemiresistor sensor for carbon dioxide
Sira Srinives1, Tapan Sarkar1, Raul Hernandez1
1Department of Chemical and Environmental Engineering, University of California-Riverside, Riverside, CA 92521, USA.
Abstract:
A carpet-like nanostructure of polyaniline (PANI) nanothin film functionalized with poly(ethyleneimine), PEI, was used as a miniature chemiresistor sensor for detection of CO2 at room temperature. Good sensing performance was observed upon exposing the PEI-PANI device to 50-5000 ppm CO2 in presence of humidity with negligible interference from ammonia, carbon monoxide, methane and nitrogen dioxide. The sensing mechanism relied on acid-base reaction, CO2 dissolution and amine-catalyzed hydration that yielded carbamates and carbonic acid for a subsequent pH detection. The sensing device showed reliable results in detecting an unknown concentration of CO2 in air.
