Carbon Nanomaterials - Poly(3-octylthiophene-2,5-diyl) – Hydrous Iridium Dioxide Triple Composite Materials as Superhydrophobic Layers for Ion-Selective Electrodes

Abstract

In this paper, we introduce a new triple composite material consisting of three significantly different materials: carbon nanomaterial (carbon nanotubes and carbon black), conducting polymer (poly(3-octylthiophene-2,5-diyl), and metal oxide (hydrous iridium dioxide). Combining these three components creates superhydrophobic materials (of contact angle value up to 180). Both designed materials were characterized with high values of electrical capacitance parameters (1.5 and 0.9 mF) and low values of resistance (72.90.3 k and 23.50.2 k for NT-based and CB-based electrode, respectively). The new functional material was implemented in potassium-selective electrodes to improve their electrical and analytical parameters. This is the first potentiometric sensor with a solid-contact layer composed of three significantly different materials. The superhydrophobic layer of triple composite material improved long-term stability (characterized by potential drift of 43 and 79 μV/h for the NT-based and CB-based electrode, respectively) and its repeatability limits the number of necessary calibrations. Potentiometric sensors presented in the scope of this work enable potassium determination in the wide range of potassium ions (from 10-6 to 10-1 M of K+ ions). The possibility of practical application was successfully confirmed by the analysis of potassium in vegetable juices.

Recent advances in nanomaterial-based solid-contact ion-selective electrodes

“…For example, the CNT–polymer nanocomposite is a typical material used in SC-ISEs to increase mechanical stability, alongside flexibility and conductivity. 171,172 Paczosa-Bator et al 173 reported the construction of super-hydrophobic nanocomposite layers consisting of MWCNTs, carbon black, poly(3-octylthiophene-2,5-diyl), and hydrous iridium dioxide for K + determination. Michalska and co-workers 174 developed the MWCNT–poly(3-octylthiophene-2,5-diyl) (POT) nanocomposite as a transducer layer to promote the sensing performance of the electrode for the detection of K + .…”

Ion-Selective Electrodes with Solid Contact Based on Composite Materials: A Review

“…An interesting solution was presented by the authors in article [147], proposing ternary nanocomposites consisting of three types of materials: conductive polymer (poly(3octylthiophene-2,5-diyl)), carbon nanomaterials (carbon black and nanotubes) and metal oxide (hydrated iridium dioxide). The obtained materials were characterized by high hydrophobicity (contact angle up to 180 • ).…”

Application of Metal Oxide Nanoparticles in the Field of Potentiometric Sensors: A Review

“…The layer of IrO 2 -POT-MWCNT turned out to be superhydrophobic with a contact angle of 178 • , which resulted in great stability in potentiometric response and long lifetime. This layer was introduced in K + [110] and H + [111] selective electrodes.…”