Single Polypyrrole Nanowire Ammonia Gas Sensor

Abstract

We report the synthesis, electrical characterization and ammonia gas sensing with single nanowire of conducting polypyrrole. Three hundred nanometer in diameter and 50 to 60 mm long polypyrrole nanowires were synthesized by chemical polymerization inside SiO 2 coated alumina membranes. Temperature dependent electrical resistance studies established that the chemically synthesized nanowires were more ordered compared to electrochemically synthesized nanowires. We further demonstrated that gas sensors based on single polypyrrole nanowire exhibited good sensitivity towards ammonia, and provided a reliable detection at concentration as low as approximately 40 ppm.

Ammonia Gas Sensor Using Polypyrrole‐Coated TiO2/ZnO Nanofibers

“…Similar phenomena have been observed for most PPy-based NH 3 sensors [13,14,16,17,19,31]. Mechanism of NH 3 sensing irreversibility is not yet clearly established, but there are various explanations such as an irreversible electron transfer from ammonia to the doped PPy matrix [16], function of the dopants on the film morphologies [13], or the detachment of the dopant molecules under pumping [29]. Further insight into the mechanism of the irreversibility is provided by comparing the high resolution XPS spectra of the N 1s region for the sample before and after NH 3 -treatment (Fig.…”

“…The complete reversibility can not been obtained in our case even though longer recovery time is used. Similar phenomena have been observed for most PPy-based NH 3 sensors [13,14,16,17,19,31]. Mechanism of NH 3 sensing irreversibility is not yet clearly established, but there are various explanations such as an irreversible electron transfer from ammonia to the doped PPy matrix [16], function of the dopants on the film morphologies [13], or the detachment of the dopant molecules under pumping [29].…”

Preparação e caracterização elétrica de sensores de metanol à base de nanocompósitos híbridos de polipirrol/nanopartículas metálicas

“…Os resultados de absorção óptica foram usados no presente trabalho por fornecer importante informação acerca do nível de dopagem, correlacionando os picos em 540 e 700 nm aos estados neutro, polarônico e bipolarônico na banda de energia do PPy [20,21] . A partir dos resultados apresentados na Figura 2 verificamos que o acréscimo na absorbância para comprimento de onda na ordem de 700 nm caracteriza a formação de níveis bipolarônicos [22,23,31] .…”

“…que tratam do processo de detecção da amônia por sensores de polipirrol [20][21][22][23] . Nesta situação, a forma protonada do PPy interage com o gás, que então estabelece a desprotonação do átomo de nitrogênio do polipirrol [20] , caracterizando esse como um processo irreversível, em que se tem uma diminuição na condutividade da amostra, que vem a caracterizar a detecção do volátil [20] .…”

Fabrication of Conjugated Polymer Nanowires by Edge Lithography

“…[1][2][3][4][5] We measured conductivity through groups of 50 to several hundred of these nanowires, which can have cross sectional widths and heights of ∼100 nm, over distances as long as 100 µm. Polymer nanowires are versatile structures that are sensitive chemical 6,7 and biological 8 sensors, field-effect transistors, [9][10][11] interconnects in electronic circuitry, 12 and tools for studying one-dimensional charge transport in materials. 13 Of the methods available for the fabrication of conjugated polymer nanowires, most are specific to certain combinations of materials and substrates, and many require expensive or specialized equipment.…”