Oxidized Carbon Nanohorn-Hydrophilic Polymer Nanocomposite as the Resistive Sensing Layer for Relative Humidity

This study presents relative humidity (RH) sensing response of resistive sensors composed of nanocomposites with oxidized single-wall carbon nanohorns (SWCNHs) and hydrophilic polymers in different ratios at room temperature. The poly(ethylene glycol)-blockpoly(propylene glycol)-block-poly(ethylene...

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Bibliographic Details
Published in:Analytical letters 2021-02, Vol.54 (3), p.527-540
Main Authors: Serban, Bogdan Catalin, Buiu, Octavian, Dumbravescu, Nicolae, Cobianu, Cornel, Avramescu, Viorel, Brezeanu, Mihai, Bumbac, Marius, Pachiu, Cristina, Nicolescu, Cristina Mihaela
Format: Article
Language:English
Subjects:
Carbon
Humidity
Humidity sensor
Hydrophilicity
Materials selection
Nanocomposites
oxidized single wall carbon nanohorns
Polyethylene glycol
Polymers
Polyvinylpyrrolidone
Propylene
Relative humidity
Response time
Room temperature
Silicon dioxide
Silicon substrates
Stability analysis
swelling
Water chemistry
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Summary:This study presents relative humidity (RH) sensing response of resistive sensors composed of nanocomposites with oxidized single-wall carbon nanohorns (SWCNHs) and hydrophilic polymers in different ratios at room temperature. The poly(ethylene glycol)-blockpoly(propylene glycol)-block-poly(ethylene glycol) (PEG-PPG-PEG) and polyvinylpyrrolidone (PVP) materials were selected to be the hydrophilic polymers. Two types of nanocomposites with PVP were synthesized, one using SWCNHs/VP at 1/2 (w/w) ratio and another with SWCNHs/PVP in a 1/1 (w/w) ratio. The sensing structure is composed of a Si substrate, a SiO 2 layer, and interdigitated (IDT) electrodes, on which the sensing layer is deposited via the drop-casting method. The sensor has a response comparable to that of a commercially available, state-of-the-art, capacitive relative humidity sensor, being characterized by a rapid response time and excellent stability with time. Two sensing mechanisms are considered and analyzed. The first involves the rapid swelling of the host hydrophilic polymer at higher relative humidity levels. The second involves a decrease in the number of holes due to interaction with water molecules, which act as electron donors.
ISSN:0003-2719
1532-236X
DOI:10.1080/00032719.2020.1772805