Issue 12, 2016

Low-cost microarray thin-film electrodes with ionic liquid gel-polymer electrolytes for miniaturised oxygen sensing

Abstract

A robust, miniaturised electrochemical gas sensor for oxygen (O2) has been constructed using a commercially available Pt microarray thin-film electrode (MATFE) with a gellified electrolyte containing the room temperature ionic liquid (RTIL) 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C2mim][NTf2]) and poly(methyl methacrylate) (PMMA) in a 50 : 50 mass ratio. Diffusion coefficients and solubilities for oxygen in mixtures of PMMA/RTIL at different PMMA doping concentrations (0–50% mass) were derived from potential step chronoamperometry (PSCA) on a Pt microdisk electrode. The MATFE was then used with both the neat RTIL and 50% (by mass) PMMA/RTIL gel, to study the analytical behavior over a wide concentration range (0.1 to 100 vol% O2). Cyclic voltammetry (CV) and long-term chronoamperometry (LTCA) techniques were employed and it was determined that the gentler CV technique is better at higher O2 concentrations (above 60 vol%), but LTCA is more reliable and accurate at lower concentrations (especially below 0.5% O2). In particular, there was much less potential shifting (from the unstable Pt quasi-reference electrode) evident in the 50% PMMA/RTIL gel than in the neat RTIL, making this a much more suitable electrolyte for long-term continuous oxygen monitoring. The mass production and low-cost of the electrode array, along with the minimal amounts of RTIL/PMMA required, make this a viable sensing device for oxygen detection on a bulk scale in a wide range of environmental conditions.

Graphical abstract: Low-cost microarray thin-film electrodes with ionic liquid gel-polymer electrolytes for miniaturised oxygen sensing

Article information

Article type
Paper
Submitted
03 Nah 2016
Accepted
25 Nah 2016
First published
25 Nah 2016
This article is Open Access
Creative Commons BY license

Analyst, 2016,141, 3705-3713

Low-cost microarray thin-film electrodes with ionic liquid gel-polymer electrolytes for miniaturised oxygen sensing

J. Lee and D. S. Silvester, Analyst, 2016, 141, 3705 DOI: 10.1039/C6AN00281A

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