Rapid-Response and Wide-Range pH Sensors Enabled by Self-Assembled Functional PAni/PAA Layer on No-Core Fiber

Long, Gang; Wan, Liang; Xia, Binyun; Zhao, Chao; Niu, Kunpeng; Hou, Jun; Lyu, Dajuan; Li, Litong; Zhu, Fang; Wang, Ning

doi:10.3390/ma15217449

Cited by 4 publications

(3 citation statements)

References 39 publications

(49 reference statements)

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“…The PAni powder was first synthesized by the typical chemical oxidative polymerization method [ 21 ]. During the synthesis processes, 10 mL of 0.4 M HCl solution was prepared and divided into two equal volumes.…”

Section: Methodsmentioning

confidence: 99%

“…The green layer representing the PAA/PAni composite film is coated onto the COFI’s surface. When the light transports into the NCF from the SMF, multiple modes will be excited, resulting in multimode interference [ 21 ]. The mth-order interference peak wavelength can be expressed by

where

is the effective RI difference between the fundamental and higher-order modes.…”

Section: Methodsmentioning

confidence: 99%

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Polyacrylic Acid/Polyaniline-Coated Multimode Interferometer for Ammonia Detection

et al. 2023

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A coaxial optical fiber interferometer (COFI) is proposed here for ammonia sensing, which comprises two light-carrying single-mode fibers (SMF) fused to a section of no-core fiber (NCF), thus forming an optical interferometer. The outer surface of the COFI is coated with a layer of polyacrylic acid (PAA)/polyaniline (PAni) film. The refractive index (RI) of the sensitive layer varies when PAA/PAni interacts with ammonia, which leads to the resonance wavelength shift. The surface morphology and structure of the PAA/PAni composites were characterized by using a scanning electron microscope (SEM) and Fourier-transform infrared (FTIR) spectroscopy. When the sensor was exposed to an ammonia atmosphere of different concentrations at room temperature, the sensing performance of the PAA/PAni composite film was superior to that of a sensitive film formed by single-component PAA or PAni. According to the experimental results, the composite film formed by 5 wt% PAA mixed with 2 wt% PAni shows better performance when used for ammonia sensing. A maximum sensitivity of 9.8 pm/ppm was obtained under the ammonia concentration of 50 ppm. In addition, the sensor shows good performance in response time (100 s) and recovery time (180 s) and has good stability and selectivity. The proposed optical fiber ammonia sensor is adapted to monitor leakage in its production, storage, transportation, and application.

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Section: Methodsmentioning

confidence: 99%

where

is the effective RI difference between the fundamental and higher-order modes.…”

Section: Methodsmentioning

confidence: 99%

Polyacrylic Acid/Polyaniline-Coated Multimode Interferometer for Ammonia Detection

et al. 2023

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“…Optical fiber sensors are widely used for pH sensing because of their great advantages. Long et al [10] fabricated and studied a rapid-response and wide-range pH sensor enabled by a self-assembled functional polyaniline/polyacrylic acid (PAni/PAA) layer on no-core fiber. The developed sensor is high in sensitivity and quick in both response and recovery time, which is promising for detecting pH in the liquid phase with temperature variation.…”

mentioning

confidence: 99%