Plasma-enabled sensing of urea and related amides on polyaniline

Abstract

The atmospheric pressure plasma jet (APPJ) was used to enhance the sensitivity of industrially important polyaniline (PANI) for detection of organic vapors from amides. The gas sensing mechanism of PANI is operating on the basis of reversible protonation or deprotonation, whereas the driving force to improve the sensitivity after plasma modifications is unknown. Herein we manage to solve this problem and investigate the sensing mechanism of atmospheric plasma treated PANI for vapor detection of amides using urea as a model. The results from various analytical techniques indicate that the plausible mechanism responsible for the improved sensitivity after plasma treatment is operating through a cyclic transition state formed between the functional groups introduced by plasma treatment and urea. This transition state improved the sensitivity of PANI towards 15 ppm of urea by a factor of 2.4 times compared to the non-treated PANI. This plasma treated PANI is promising for the improvement of the sensitivity and selectivity towards other toxic and carcinogenic amide analytes for gas sensing applications such as improving material processing and controlling food quality.

Ammonia plasma-treated carbon nanotube/epoxy composites and their using in sensing applications

“…The peak at 3423 cm -1 of stretching vibrations of isolated surface -OH moieties and/or -OH in carboxyl groups [31] in Figure 4a is shifted to higher and lower wavenumber in FTIR spectra of MWCNT(plas -ma40) and MWCNT(plasma300), respectively. In addition, N-H stretching absorption peaks induced by ammonia plasma treatment appeared in the 3500-3300 cm -1 region [32], which could contribute to this shift. In the range of 2800-3000 cm -1 new C-H peaks [33] have been seen in FTIR spectra of plasma-treated MWCNTs, which indicate that the opening of phenyl rings and their hydrogenation [29] occur during the plasma treatment.…”

White paper on the future of plasma science and technology in plastics and textiles

“…Nevertheless, the underlying mechanism remained elusive. In a recent study, researchers proposed a mechanism, taking amide like compounds as an example to probe the plasma functionalized PANI‐analyte interactions . It was proposed that plasma‐incorporated functional groups can improve the sensitivity and response time by bringing the interacting molecule to its proximity through a completely reversible cyclic intermediate transition state (Figure ).…”

“…(a) Response of pristine and atmospheric pressure plasma treated PANI toward 15 ppm of urea and (b) sensing mechanism in pristine and plasma modified PANI. (Reproduced with permission from Puliyalil et al Courtesy and copyright: Higher Education Press and Springer‐Verlag Berlin Heidelberg 2016…”

Synthesis and Characterization of Tin Oxide Nanopowder and Its Application to Sensing Different Pathogens

“…Metal oxides (MOs) and nanomaterials are preferred for the development of different sensors owing to their chemical stability and low production cost. (1,2) Thick-and thin-film technologies have an essential role in the manufacturing of these sensors. (3,4) Nanostructured metal oxides (NMOs) such as tin, titanium, zinc, iron, and indium oxides have attracted wide interest in the scientific community because they exhibit interesting characteristics such as biocompatibility, nontoxicity, naturally occurring nanostructures, and catalytic properties.…”