Single-Step Integration of Poly(3-Octylthiophene) and Single-Walled Carbon Nanotubes for Highly Reproducible Paper-Based Ion-Selective Electrodes

Abstract

Calibration of ion-selective electrodes (ISEs) is cumbersome, time-consuming, and constitutes a significant limitation for the development of single-use and wearable disposable sensors. To address this problem, we have studied the effect of ion-selective membrane solvent on ISE reproducibility by comparing tetrahydrofuran (THF) (a typical solvent for membrane preparation) and cyclohexanone. In addition, a single-step integration of semiconducting/transducer polymer poly­(3-octylthiophene) (POT) with single-walled carbon nanotubes (SWCNTs) into the paper-based ISEs (PBISEs) substrate was introduced. PBISEs for potassium and sodium ions were developed, and these ISEs present outstanding sensor performance and high potential reproducibility, as low as ±1.0 mV (n = 3).

Solid‐Contact Ion‐Selective Electrodes Paving the Way for Improved Non‐Zero Current Sensors: A Minireview

“…[29] The other group of materials that offer significant benefits as transducers in ASS-ISEs are carbon nanostructures, mainly multi-walled carbon nanotubes (MWCNTs) [30][31][32][33][34][35][36][37][38] but also other three-dimensionally ordered macroporous carbon, [39] colloidimprinted mesoporous, [40] graphene or its composites, [41][42][43] fullerenes. [44] Elimination of some drawbacks of classical systems as well as significant advantages are offered by application of composite materials, among others prepared from carbon nanostructures and conducting polymers, [45][46][47][48] e. g. poly (octylthiophene) and carbon nanotubes. Composites can be also prepared by introducing redox systems to the ion-selective membrane [49][50][51] or systems that are not a classical redox pair.…”

Ionophore-based ion-selective electrodes: signal transduction and amplification from potentiometry

“…ISEs are advantageous due to their versatility, low cost and power consumption, and high selectivity due to a variety of ionophores. 1,[3][4][5][6][7][8][9][10][11][12][13][14] The potentiometric sensor response has been theoretically well described by the phase-boundary potential model. 15 The Nikolsky-Eisenman formula and Bakker's modification can be used to account for interfering ions.…”

Porous carbon-based robust, durable, and flexible electrochemical device for K+ detection in sweat

“…Moreover, ISMs usually have a weak attachment to the solid contact, resulting in poor ion-electron transduction and even the detachment of the membrane in use. 9 To address these problems, different strategies have been employed, such as depositing conducting polymers, 10,11 fabricating high-surfacearea structures, 12,13 and employing covalent attachment. 9 Conductive materials with ion/electron conduction properties, such as conducting polymers, metal nanomaterials, and carbon-based materials, were generally applied as a solid contact between the ISM and the electrode.…”

“…For example, Rostampour et al integrated poly(3-octylthiophene) (POT) and single-walled carbon nanotubes (SWCNTs) into a paper-based ISEs (PBISEs) substrate, which presented outstanding sensor performance and high potential reproducibility, as low as ±1.0 mV (n = 3). 10 To address the problems of the sensor stability and reliability caused by poor ISM-conductor attachment, Roy et al utilized porous carbon nanotube (CNT) electrodes instead of flat Au, Pt and carbon electrodes. 12 The ISM filled the intertubular spaces of the highly porous CNT film and formed an attachment, which significantly enhanced the stability and repeatability of the solid-state ion sensor.…”