Designing polymeric sensing materials: what are we doing wrong?

Abstract

Gas analytes, or volatile organic compounds, interact with polymeric sensing materials through various sensing mechanisms. The dominant sensing mechanisms are discussed for different types of volatile organic compounds, which are categorized by their functional groups. Based on these sensing mechanisms, a systematic approach is used to design and tailor polymeric sensing materials for specific analytes and applications. This approach also takes into consideration other constraints determined by the target application. We include practical prescriptions on how to efficiently and cost‐effectively design, tailor, and select potential polymeric sensing materials, as well as how to evaluate these sensing materials. Copyright © 2016 John Wiley & Sons, Ltd.

Investigation of the Interaction between Benzene and SXFA Using DFT

“…While this orientation of the carbon tetrafluoride-benzene complex agrees with the proposed sorption of benzene to SXFA, it has been shown that this orientation may not be explained by π-stacking, but rather charge transfer between the small molecules that reduces the electron density in the π-system [17]. A sensing mechanism was subsequently suggested in which benzene π-stacks onto one of the trifluoro-groups on SXFA, since the fluorine atoms form a planar ring (see Figure 2) [8]. This paper evaluates the proposed sensing mechanism between benzene and SXFA using a DFT approach.…”

“…To more efficiently design and tailor polymeric sensing materials for target analytes and specific applications, it is important to understand the sensing mechanisms by which analytes (and interferents) interact with sensing materials [8]. One way to investigate these sensing mechanisms is with Density Functional Theory (DFT) calculations [9,10].…”

“…In all cases, SXFA was exposed to gaseous benzene, resulting in benzene adsorbing onto the sensing material, causing a measurable frequency shift on the RFID sensors (see Figure 1b), with sensitivities (per percent frequency shift) of 5.92 × 10 −4 /%, 5.05 × 10 −4 /%, and 9.1 × 10 −5 /% for RFID 1, RFID 2, and RFID 3, respectively [14,15]. A sensing mechanism was subsequently suggested in which benzene π-stacks onto one of the trifluoro-groups on SXFA, since the fluorine atoms form a planar ring (see Figure 2) [8]. This paper evaluates the proposed sensing mechanism between benzene and SXFA using a DFT approach.…”

Evaluation of doped and undoped poly (o‐anisidine) as sensing materials for a sensor array for volatile organic compounds

“…This immediately reduces the amount of analyte molecules that are available to sorb. Also, as more gas analytes are simultaneously exposed to a sensing material, they compete for available sorption (sensing) sites . This often results in lower sorption of each gas analyte, which can be seen in Figures .…”

“…For example, such a sensor array could be one consisting of PoANI, poly (vinyl pyrrolidone) (PVP), poly (2,5‐dimethyl aniline) (P25DMA), and SXFA . These potential sensing materials were chosen because each one has acceptable partial selectivity to one of the four gas analytes evaluated in this paper; PoANI to acetone, PVP to ethanol, P25DMA to methanol, and SXFA to benzene.…”