Carbon dioxide gas sensor with ionic gel

Abstract

This paper reports on a low-power-consumption carbon dioxide (CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ) gas sensor based on an ionic gel. Ionic gel is a mixture of ionic liquid and polymer. We employed 1-ethyl-3-methyl-imidazolium tetrafuloroborate ([EMIM][BF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> ]) as ionic liquid and polyvinylidene fluoridecohexafluoro propylene (PVDF-HFP) as polymer. The [EMIM][BF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> ] selectively absorbs CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> gas. Our proposal sensor consisted of an ionic gel and two Pt electrodes patterned under the ionic gel. The CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> gas concentration can be detected by measuring the electrochemical impedance between the two electrodes. The sensor was able to measure the difference of 500 ppm CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> gas concentration by using power as small as 0.65 μW.