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14 pages, 5693 KiB

Open AccessArticle

Synthesis and Application of Polymer SXFA in the Detection of Organophosphine Agents with a SAW Sensor

by Cancan Yan, Molin Qin, Tengxiao Guo, Lin Zhang, Junchao Yang and Yong Pan

Polymers 2024, 16(6), 784; https://doi.org/10.3390/polym16060784 - 12 Mar 2024

Cited by 4 | Viewed by 1610

The effective detection of isopropyl methylfluorophosphonate (GB, sarin), a type of organophosphine poisoning agent, is an urgent issue to address to maintain public safety. In this research, a gas-sensitive film material, poly (4-hydroxy-4,4-bis trifluoromethyl)-butyl-1-enyl)-siloxane (SXFA), with a structure of hexafluoroisopropyl (HFIP) functional group was synthesized by using methyl vinylpropyl dichlorosilane and hexafluoroacetone trihydrate as initial materials. The synthesis process products were characterized using FTIR. SXFA was prepared on a 200 MHz shear surface wave delay line using the spin-coating method for GB detection. A detection limit of <0.1 mg/m³ was achieved through conditional experiments. Meanwhile, we also obtained a maximum response of 2.168 mV at a 0.1 mg/m³ concentration, indicating the much lower detection limit of the SAW-SXFA sensor. Additionally, a maximum response standard deviation of 0.11 mV with a coefficient of variation of 0.01 and a maximum recovery standard deviation of 0.22 mV with a coefficient of variation of 0.02 were also obtained through five repeated experiments. The results show that the SAW-SXFA sensor has strong selectivity and reproducibility, good selectivity, positive detection ability, high sensitivity, and fast alarm performance for sarin detection. Full article

(This article belongs to the Special Issue Polymer Materials in Sensors, Actuators and Energy Conversion II)

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6 pages, 1603 KiB

Open AccessArticle

Investigation of the Interaction between Benzene and SXFA Using DFT

by Katherine M. E. Stewart, Ian P. Hamilton and Alexander Penlidis

Processes 2018, 6(2), 10; https://doi.org/10.3390/pr6020010 - 25 Jan 2018

Cited by 2 | Viewed by 5093

Abstract

Density Functional Theory (DFT) studies were conducted to evaluate the sensing mechanism between benzene and a polymeric sensing material, referred to as SXFA, which contains trifluoro-groups and OH-groups. These studies were undertaken to improve the understanding of how benzene and SXFA mechanistically interact based on their chemistry, information which can be used to more efficiently design polymeric sensing materials. We find that benzene adsorbed onto the OH-groups in SXFA rather than the trifluoro-groups as previously proposed. Specifically, we find that sorption results from electrostatic attraction between the negative benzene ring and the positive hydrogens of the OH-groups of SXFA. Full article

(This article belongs to the Collection Process System Engineering for More Efficient Power and Chemicals Production)

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12 pages, 2376 KiB

Open AccessArticle

Development of a Wireless and Passive SAW-Based Chemical Sensor for Organophosphorous Compound Detection

by Fang-Qian Xu, Wen Wang, Xu-Feng Xue, Hao-Liang Hu, Xin-Lu Liu and Yong Pan

Sensors 2015, 15(12), 30187-30198; https://doi.org/10.3390/s151229793 - 3 Dec 2015

Cited by 23 | Viewed by 8182

Abstract

A new wireless and passive surface acoustic wave (SAW)-based chemical sensor for organophosphorous compound (OC) detection is presented. A 434 MHz reflective delay line configuration composed by single phase unidirectional transducers (SPUDTs) and three shorted reflectors was fabricated on YZ LiNbO₃ piezoelectric substrate as the sensor element. A thin fluoroalcoholpolysiloxane (SXFA) film acted as the sensitive interface deposited onto the SAW propagation path between the second and last reflectors of the SAW device. The first reflector was used for the temperature compensation utilizing the difference method. The adsorption between the SXFA and OC molecules modulates the SAW propagation, especially for the time delay of the SAW, hence, the phase shifts of the reflection peaks from the corresponding reflectors can be used to characterize the target OC. Prior to the sensor fabrication, the coupling of modes (COM) and perturbation theory were utilized to predict the SAW device performance and the gas adsorption. Referring to a frequency-modulated continuous wave (FMCW)-based reader unit, the developed SAW chemical sensor was wirelessly characterized in gas exposure experiments for dimethylmethylphosphonate (DMMP) detection. Sensor performance parameters such as phase sensitivity, repeatability, linearity, and temperature compensation were evaluated experimentally. Full article

(This article belongs to the Section Chemical Sensors)

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16 pages, 1151 KiB

Open AccessArticle

Advances in SXFA-Coated SAW Chemical Sensors for Organophosphorous Compound Detection

by Wen Wang, Shitang He, Shunzhou Li, Minghua Liu and Yong Pan

Sensors 2011, 11(2), 1526-1541; https://doi.org/10.3390/s110201526 - 27 Jan 2011

Cited by 39 | Viewed by 10143

Abstract

A polymer-coated surface acoustic wave (SAW)-based chemical sensor for organophosphorous compound sensing at extremely low concentrations was developed, in which a dual-delay-line oscillator coated with fluoroalcoholpolysiloxane (SXFA) acted as the sensor element. Response mechanism analysis was performed on the SXFA-coated chemical sensor, resulting in the optimal design parameters. The shear modulus of the SXFA, which is the key parameter for theoretical simulation, was extracted experimentally. New designs were done on the SAW devices to decrease the insertion loss. Referring to the new phase modulation approach, superior short-term frequency stability (±2 Hz in seconds) was achieved from the SAW oscillator using the fabricated 300 MHz delay line as the feedback element. In the sensor experiment on dimethylmethylphosphonate (DMMP) detection, the fabricated SXFA-coated chemical sensor exhibited an excellent threshold detection limit up to 0.004 mg/m³ (0.7 ppb) and good sensitivity (~485 Hz/mg/m³ for a DMMP concentration of 2~14 mg/m³). Full article

(This article belongs to the Section Chemical Sensors)

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