Ion-Solvent Interactions

doi:10.1007/0-306-46909-x_2

Cited by 1 publication

(1 citation statement)

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“…The ethanol spraying implies a decrease of the total resistance of the systems (Figure 10a,c,d,f). A Grotthus-like proton "jumping" conduction mechanism [60], mediated by hydrogen bonding with the PVP-and Citrate-capped Au NPs [61,62], may be responsible for the higher charge transport rate (i.e., lower overall resistance) caused by the ethanol/water solution. Nonetheless, a low-water ionic product (K w = 10 −14 ) and ethanol small acid constant (pK a = 16) still pinned the overall resistance in the tens of MΩ range.…”

Section: Electrical Measurementsmentioning

confidence: 99%

Gold Nanoparticles-Functionalized Cotton as Promising Flexible and Green Substrate for Impedometric VOC Detection

Casalinuovo,

Caschera,

Quaranta

et al. 2023

Materials

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This work focuses on the possible application of gold nanoparticles on flexible cotton fabric as acetone- and ethanol-sensitive substrates by means of impedance measurements. Specifically, citrate- and polyvinylpyrrolidone (PVP)-functionalized gold nanoparticles (Au NPs) were synthesized using green and well-established procedures and deposited on cotton fabric. A complete structural and morphological characterization was conducted using UV–VIS and Fourier transform infrared (FT–IR) spectroscopy, atomic force microscopy (AFM), and scanning electron microscopy (SEM). A detailed dielectric characterization of the blank substrate revealed interfacial polarization effects related to both Au NPs and their specific surface functionalization. For instance, by entirely coating the cotton fabric (i.e., by creating a more insulating matrix), PVP was found to increase the sample resistance, i.e., to decrease the electrical interconnection of Au NPs with respect to citrate functionalized sample. However, it was observed that citrate functionalization provided a uniform distribution of Au NPs, which reduced their spacing and, therefore, facilitated electron transport. Regarding the detection of volatile organic compounds (VOCs), electrochemical impedance spectroscopy (EIS) measurements showed that hydrogen bonding and the resulting proton migration impedance are instrumental in distinguishing ethanol and acetone. Such findings can pave the way for the development of VOC sensors integrated into personal protective equipment and wearable telemedicine devices. This approach may be crucial for early disease diagnosis based on nanomaterials to attain low-cost/low-end and easy-to-use detectors of breath volatiles as disease markers.

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Section: Electrical Measurementsmentioning

confidence: 99%