Hybrid layer-by-layer (LbL) films of polyaniline, graphene oxide and zinc oxide to detect ammonia

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• 作者：Rafaela S. Andre^a ; ^b ; ^{rafaela.s.a@outlook.com" class="auth_mail" title="E-mail the corresponding author} ; Flá ; vio M. Shimizu^a ; ^c ; Celina M. Miyazaki^d ; Antonio Riul Jr^e ; Danilo Manzani^f ; Sidney J.L. Ribeiro^f ; Osvaldo N. Oliveira Jr^c ; Luiz H.C. Mattoso^a ; ^b ; Daniel S. Correa^a ; ^b ; ^{daniel.correa@embrapa.br" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Ammonia sensor ; Graphene oxide ; Polyaniline ; Impedance spectroscopy ; Nanostructured film
• 刊名：Sensors & Actuators: B. Chemical
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：238
• 期：Complete
• 页码：795-801
• 全文大小：1702 K

文摘

Reliable gas sensors operating at room temperature are in demand for monitoring the environment for hazardous pollutants, such as ammonia (NH₃) gas that may become toxic to humans and animals above a threshold concentration. In this paper we report on the combination of three materials, namely polyaniline (PANI), graphene oxide (GO) and zinc oxide (ZnO), to produce hybrid layer-by-layer (LbL) films used for sensing NH₃ with impedance spectroscopy measurements. The deposition of tetralayered PANI/GO/PANI/ZnO LbL films was confirmed with UV–vis. absorption and Raman spectroscopies, while atomic force microscopy (AFM) served to investigate film morphology. Exposure of these LbL films to NH₃ caused film roughness to vary, in an effect that depended on the number of tetralayers. Because of synergy in the materials properties, the films with 3 tetralayers were found to be the most adequate for detecting NH₃ in the range from 25 ppm to 500 ppm with a response time of 30 s. These figures of merit are adequate for monitoring working environments regarding gas exposure, and highlight the usefulness of the control of film architecture provided by the LbL technique.