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Title: Ionic Liquid-Packed Microfluidic Device with Non-Planar Microelectrode as a Miniaturized Electrochemical Gas Sensor
Integrating transducer/sensing materials into microfluidic platforms has enhanced gas sensors′ sensitivity, selectivity, and response time while facilitating miniaturization. In this manuscript, microfluidics has been integrated with non-planar microelectrode array and functionalized ionic liquids (ILs) to develop a novel miniaturized electrochemical gas sensor architecture. The sensor employs the IL 1-ethyl-3-methylimidazolium 2-cyanopyrolide ([EMIM][2-CNpyr]) as the electrolyte and capture molecule for detecting carbon dioxide (CO 2 ). The three-layer architecture of the sensor consists of a microchannel with the IL sandwiched between glass slides containing microelectrode arrays, forming a non-planar structure. This design facilitates electric field penetration through the IL, capturing CO 2 binding perturbations throughout the channel volume to enhance sensitivity. CO 2 binding with [EMIM][2-CNpyr] generates carboxylate ([EMIM] + -CO2 − ]), carbamate ([2-CNpyr]-CO2 − ]), and pyrrole-2-carbonitrile (2-CNpyrH) species, significantly decreasing the conductivity. The viscosity is also increased, leading to a further decrease in conductivity. These cumulative effects increase charge transfer resistance in the impedance spectrum, allowing a linear calibration curve obtained using Langmuir Isotherm. The sensitivity and reproducibility in CO 2 detection are demonstrated by two electrode configurations using the calibration curve. The developed sensor offers a versatile platform for future applications.  more » « less
Award ID(s):
1751759 2048361 1904592
PAR ID:
10462653
Author(s) / Creator(s):
; ; ; ; ; ; ;
Date Published:
Journal Name:
Journal of The Electrochemical Society
Volume:
170
Issue:
8
ISSN:
0013-4651
Page Range / eLocation ID:
087508
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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