Here, we investigate the interactions between five representative gaseous analytes and two poly(ionic liquids) (PILs) based on the sulfopropyl acrylate polyanion in combination with the alkylphosphonium cations, P4,4,4,4 and P4,4,4,8, and their nanocomposites with fullerenes (C60, C70) to reveal the potential of PILs as sensitive layers for gas sensors. The gaseous analytes were chosen based on their molecular size (all of them containing two carbon atoms) and variation of functional groups: alcohol (ethanol), nitrile (acetonitrile), aldehyde (acetaldehyde), halogenated alkane (bromoethane), and carboxylic acid (acetic acid). The six variations of PILs-P4,4,4,4SPA (1), P4,4,4,4SPA + C60 (1 + C60), P4,4,4,4SPA + C70 (1 + C70), and P4,4,4,8SPA (2), P4,4,4,8SPA + C60 (2 + C60), P4,4,4,8SPA + C70 (2 + C70)-were characterized by UV-vis and Raman spectroscopy, and their interactions with each gaseous analyte were studied using electrochemical impedance spectroscopy. Exposure of all PIL samples to acetaldehyde, bromoethane, and ethanol leads to a decrease in the diffusion coefficient, while exposure to acetic acid reveals an increase. Fullerene-doping significantly enhances the response to the analyte. Semiempirical quantum mechanical xTB-GFN2 calculations revealed that hydrogen bonding and proton transfer events play an important role during the detection process.

• Publikační typ
• časopisecké články MeSH

Nafion possesses many interesting properties such as a high ion-conductivity, hydrophilicity, and thermal and chemical stability that make this material highly suitable for many applications including fuel cells and various (bio-)chemical and physical sensors. However, the mechanical properties of a Nafion membrane that are known to be affected by the viscoplastic characteristics of the material itself have a strong impact on the performance of Nafion-based sensors. In this study, the mechanical properties of Nafion under the cyclic loading have been investigated in detail. After cyclic tensile loading (i.e., maximum elongation about 25% at a room temperature and relative humidity about 40%) a time-dependent recovery comes into play. This recovery process is also shown being strain-rate dependent. Our results reveal that the recovery behavior weakens after performing several stress-strain cycles. Present findings can be of a great importance in future design of various chemical and biological microsensors and nanosensors such as hydrogen or glucose ones.

• Klíčová slova
• Nafion, cyclic loading, mechanical properties, mechanical tests, viscoplastic properties,
• Publikační typ
• časopisecké články MeSH

Solid polymer electrolytes show their potential to partially replace conventional electrolytes in electrochemical devices. The solvent evaporation rate represents one of many options for modifying the electrode-electrolyte interface by affecting the structural and electrical properties of polymer electrolytes used in batteries. This paper evaluates the effect of solvent evaporation during the preparation of solid polymer electrolytes on the overall performance of an amperometric gas sensor. A mixture of the polymer host, solvent and an ionic liquid was thermally treated under different evaporation rates to prepare four polymer electrolytes. A carbon nanotube-based working electrode deposited by spray-coating the polymer electrolyte layer allowed the preparation of the electrode-electrolyte interface with different morphologies, which were then investigated using scanning electron microscopy and Raman spectroscopy. All prepared sensors were exposed to nitrogen dioxide concentration of 0-10 ppm, and the current responses and their fluctuations were analyzed. Electrochemical impedance spectroscopy was used to describe the sensor with an equivalent electric circuit. Experimental results showed that a higher solvent evaporation rate leads to lower sensor sensitivity, affects associated parameters (such as the detection/quantification limit) and increases the limit of the maximum current flowing through the sensor, while the other properties (hysteresis, repeatability, response time, recovery time) change insignificantly.

• Klíčová slova
• gas sensor, ionic liquid, noise spectroscopy, solid polymer electrolyte,
• Publikační typ
• časopisecké články MeSH