Fabrication of Conducting Polyaniline–Betel Nut Fiber Filaments with Potential Ammonia Gas Sensing Behavior

ABSTRACT

Polyaniline–betel nut fiber (PANI/BNF) filaments have been prepared for the first time by in situ polymerization with potential application as ammonia gas sensor at room temperature. A sheath of polyaniline is formed surrounding the BNF filament, which is evident from scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR), and X-ray diffraction (XRD) analyses. This morphological structure makes it easy enough to fit the filaments directly between electrodes for resistive ammonia gas sensor studies without the need of any other polymeric matrix, indicating novelty of the work. A red shift with increase in the amount of BNF is observed in the UV–Vis spectra. The composite exhibits increased electrical conductivity as revealed by electrochemical impedance spectroscopy (EIS), which is a requisite for resistive gas sensors. The novel PANI/BNF sensor has average ammonia-sensing response of 28.2% toward 100 ppm of ammonia with 10 ppm detection limit. The sensor fits in a linear plot of response vs. NH₃ concentration from 10 to 200 ppm with good response and recovery capabilities. PANI/BNF filaments with increased conductivity, thermal stability, and ammonia-sensing properties open new scope for their application in gadgets like electrodes for supercapacitors, other gas sensors, and electromagnetic shields.

摘要

首次通过原位聚合制备了聚苯胺槟榔纤维 (PANI/BNF) 长丝, 并在室温下用作氨气传感器. 扫描电子显微镜 (SEM), 傅立叶变换红外光谱 (FTIR) 和X射线衍射 (XRD) 分析表明, 在BNF长丝周围形成聚苯胺鞘. 这种形态结构允许长丝直接安装在电阻式氨气传感器研究的电极之间, 而不需要任何其他表明其新颖性的聚合物基质. 在紫外-可见光谱中观察到随着BNF量的增加而红移. 电化学阻抗谱 (EIS) 表明, 该复合材料的电导率增加, 这是电阻式气体传感器的必要条件. 新型聚苯胺/氮化硼传感器对100 ppm氨气的平均氨气传感响应为28.2%, 检测限为10 ppm. 该传感器符合响应与NH3浓度的线性关系图, 从10 ppm到200 ppm, 具有良好的响应和恢复能力. 聚苯胺/氮化硼长丝具有更高的导电性, 热稳定性和氨传感特性, 为其在超级电容器电极, 其他气体传感器, 电磁屏蔽等器件中的应用开辟了新的领域.

KEYWORDS:

• Polyaniline
• betel nut fiber (BNF)
• electrical conductivity
• electrochemical impedance spectroscopy (EIS)
• ammonia
• sensitivity

关键词:

• 聚苯胺
• 槟榔纤维
• 电导率
• 电化学阻抗谱
• 氨
• 体贴

Highlights

• Conducting betel nut fiber–polyaniline (BNF/PANI) composite filaments were synthesized for the first time in CCl₄ using APS as oxidant and HCl as doping agent.

• Electrical impedance spectroscopy (EIS) reveals that AC electrical conductivity of the composite filaments increased with the increase in amount of aniline.

• With the increase in temperature from room temperature to 90°C, AC conductivity also increased.

• The optical property and bandgap study of the BNF/PANI composite filaments were studied by UV–Vis spectroscopy and Tauc’s equation.

• PANI/BNF composite shows excellent resistive sensing behaviour towards ammonia gas at room temperature.

Disclosure statement

No potential conflict of interest was reported by the authors.

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/15440478.2022.2104776