CO2 Gas Sensors Based on Hydrophilic Vanadium Oxide Thin Film Coated QCM

Electrical Response of Poly(N-[3-(dimethylamino)Propyl] Methacrylamide) to CO2 at a Long Exposure Period

“… 34 We explored the absorption and desorption of CO 2 by pDMAPMAm in the solid state via the QCM. 50 In this case, the deposited thin film of pDMAPMAm on the quartz sensor was placed in the QCM cell, and the target gases were passed through the system in three cycles at room temperature as follows: N 2 with a flow of 5 mL min –1 for 45 min, CO 2 with a flow of 5 mL min –1 for 1 h, and N 2 with a flow of 5 mL min –1 for 45 min. As demonstrated in Figure 12 a, the frequency values decreased considerably from −1.76 Hz to −51.74 Hz over time in the presence of CO 2 , confirming the mass increase of the specimen due to the CO 2 absorption.…”

“…Although it is known that tertiary amines deprotonate when exposed to N 2 at ambient temperature, the reversibility of polymers occasionally necessitates higher temperatures. ,, Darabi et al, for example, reported CO 2 -switchable latexes employing DMAPMAm, which could be redispersed by bubbling CO 2 at room temperature, whereas the reverse reaction (the desorption of CO 2 and the deprotonation of tertiary amine sites) needed a higher temperature (65 °C) in addition to the N 2 bubbling . We explored the absorption and desorption of CO 2 by pDMAPMAm in the solid state via the QCM . In this case, the deposited thin film of pDMAPMAm on the quartz sensor was placed in the QCM cell, and the target gases were passed through the system in three cycles at room temperature as follows: N 2 with a flow of 5 mL min –1 for 45 min, CO 2 with a flow of 5 mL min –1 for 1 h, and N 2 with a flow of 5 mL min –1 for 45 min.…”