Journal articles: 'Fluoride Sensors'

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Kropachev, Andrei N., Sergey V. Podrezov, Alexander V. Aleksakhin, Andrey A. Gudilin, Olga A. Kondratyeva, and Lyudmila N. Korshunova. "Thermodynamic Studies and Optimization of the Method for Obtaining Neodymium Fluoride for the Production of Magnetic Sensors’ Sensitive Elements." Sensors 21, no. 24 (December 15, 2021): 8361. http://dx.doi.org/10.3390/s21248361.

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Rare earth metals (REM) with magnetic properties find application in the recently developed high-tech industries. Sensor magnetic systems based on neodymium are increasingly in demand in modern engineering and geological surveys due to their favorable combination of properties of magnetic materials based on rare earth metals. One of the problems is to obtain high-quality materials for the production of such magnetic sensors. It should be noted that the high activity of REM does not allow obtaining master alloys and REM-based alloys from metallic materials; it is advisable to use halide compounds. This work discusses a method for producing neodymium fluoride from its oxide. REM fluorides can be obtained by fluorinating the oxides of these metals. Various fluorine-containing compounds or elemental fluorine are usually used as fluorinating reagents, which have their own advantages and disadvantages. The thermodynamic and technological analysis of neodymium fluoride production processes has shown the most acceptable fluorinating agent is ammonium hydrofluoride, which was used in this work. In order to increase the productivity and degree of chemical transformation, it was proposed to perform heating stepwise; i.e., at the initial stage, heat at a speed of 3 degrees per minute, after which the heating speed was reduced to 2 degrees per minute, and finally the speed was reduced to 1 degree per minute. Due to proposed heating mode, the same productivity and yield of chemical transformation were achieved, with an increased efficiency up to 30%, which can significantly reduce the cost of production. The obtained product is used in the production of neodymium-based alloys by metallothermic reduction of a mixture of fluorides. The sensor material obtained in this way is characterized by a low (less than 0.05%) oxygen content.

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Ma, Lei, Shreyes N. Melkote, John B. Morehouse, James B. Castle, James W. Fonda, and Melissa A. Johnson. "Design of thin-film polyvinylidene fluoride sensor rosettes for isolation of various strain components." Journal of Intelligent Material Systems and Structures 23, no. 10 (May 6, 2012): 1119–30. http://dx.doi.org/10.1177/1045389x12443597.

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Thin-film polyvinylidene fluoride piezoelectric sensors have long been recognized as a promising alternative to traditional metal foil strain gauges in applications where only dynamic or quasistatic signals are of interest. Compared to metal foil strain gauges, polyvinylidene fluoride sensors feature high sensitivity, high dynamic range, and broad frequency bandwidth. However, transverse sensitivity of the polyvinylidene fluoride sensor is higher than that of a metal foil strain gauge, making it more difficult to isolate a particular strain component or a deformation mode when the host structure is under complex loading. In addition, polyvinylidene fluoride films are sensitive to changes in ambient temperature due to the pyroelectric effect. In this article, three temperature-compensated polyvinylidene fluoride sensor rosette designs are proposed for isolating specific strain component(s) and deformation mode(s) of interest. First-principles based models are derived to relate the polyvinylidene fluoride sensor rosette output to the actual elastic strain component of interest. Experimental validation is conducted to verify the proposed models and to compare the performance of the polyvinylidene fluoride sensor rosettes with their metal foil strain gauge counterparts.

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Schultz, J. S. "Chemical Sensors and Biosensors for Fluoride: Current Status and Developing Technologies." Advances in Dental Research 8, no. 1 (June 1994): 100–104. http://dx.doi.org/10.1177/08959374940080010101.

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Portable sensors for bioanalytes are becoming of increasing interest, because their development will permit analyses of biological samples at the point of sampling, i.e., at the time when an individual is being examined by a health professional. In this paper, the design requirements for a fluoride sensor are outlined. Currently, commercially available fluoride sensors, ion-selective electrodes, do provide the capability to measure fluoride content in samples directly. However, the sensitivity of these devices is lower than the normal content of fluoride in plasma, and thus, samples must be concentrated before measurement. Recent progress in improving the sensitivity of chemical sensors for fluoride shows sensitivities up to 0.1 μmol/L, which is within the range of interest. In addition, the use of biological systems for developing sensors (biosensors) is expanding rapidly, because of the potential of achieving high selectivity and sensitivity through the use of the amplification power of enzymes. However, relatively few enzyme systems have been discovered that are affected by fluoride-thus the need for expanded research to find appropriate enzymes for this purpose. The characteristics of some enzymes, such as adenylate cyclase, that could be used in the development of a fluoride biosensor are discussed.

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Ma, Yuan, Quanbing Mou, Peng Yan, Zhenglin Yang, Ying Xiong, Deyue Yan, Chuan Zhang, Xinyuan Zhu, and Yi Lu. "A highly sensitive and selective fluoride sensor based on a riboswitch-regulated transcription coupled with CRISPR-Cas13a tandem reaction." Chemical Science 12, no. 35 (2021): 11740–47. http://dx.doi.org/10.1039/d1sc03508h.

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A fluoride sensor based on riboswitch-regulated transcription coupled with Cas13a sensor can detect fluoride in water with a portable fluorometer. This sensor expands nuclei acid sensors to an anion, with high sensitivity and selectivity against other common anions.

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Sun, Ying, Rui Cao, Zhan Lu, Xin Nie, Zhaokai Li, Yonghua Yu, Hongping Tian, Xiangqun Qian, and Jianping Wang. "Design and Testing of an Impact Sensor Using Two Crossed Polyvinylidene Fluoride (PVDF) Films." Transactions of the ASABE 62, no. 5 (2019): 1195–205. http://dx.doi.org/10.13031/trans.13440.

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Abstract. Impact sensors are widely used to detect grain losses in harvesters. Using polyvinylidene fluoride (PVDF) films as sensing elements is a promising way to improve sensor performance due to their high sensitivity, stability, and flexibility. However, the overlap of collision signals significantly reduces the accuracy of a sensor. To solve this problem, a novel impact sensor with two crossed PVDF films was designed and investigated. This sensor has two orthogonal layers of sensing elements that both respond to impacts, which creates positioning information for the impacts. Because of the sensor’s structure, a signal processing method was designed based on multisensor fusion theory. Tests were performed to verify the performance of the proposed impact sensor. The average signal-to-noise ratios (SNRs) for impacted PVDF films were 34.79 and 20.23 dB, respectively, for the upper and lower layers, while the average signal-to-clutter ratios (SCRs) for nonimpacted films were 21.90 and 10.05 dB, respectively. The sensor also has an extremely high detection efficiency of at least 1528 collisions per second and can identify particles that impact at the same time. Keywords: Grain loss detection, Impact sensors, Multisensor fusion, Particle impact tests, PVDF films.

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Chanmungkalakul, Supphachok, Vuthichai Ervithayasuporn, Sasikarn Hanprasit, Manlika Masik, Nicha Prigyai, and Suda Kiatkamjornwong. "Silsesquioxane cages as fluoride sensors." Chemical Communications 53, no. 89 (2017): 12108–11. http://dx.doi.org/10.1039/c7cc06647c.

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Cho, Eun Jin, Byung Ju Ryu, Young Ju Lee, and Kye Chun Nam. "Visible Colorimetric Fluoride Ion Sensors." Organic Letters 7, no. 13 (June 2005): 2607–9. http://dx.doi.org/10.1021/ol0507470.

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FREEMANTLE, MICHAEL. "Fluorescent sensors detect fluoride ions." Chemical & Engineering News 76, no. 28 (July 13, 1998): 15–16. http://dx.doi.org/10.1021/cen-v076n028.p015a.

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Lenormand, Hugo, Jean-Philippe Goddard, and Louis Fensterbank. "Spirosilane Derivatives as Fluoride Sensors." Organic Letters 15, no. 4 (January 29, 2013): 748–51. http://dx.doi.org/10.1021/ol3033048.

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Ma, Chao Zhe, Jin Song Du, and Yi Yang Liu. "Research on PVDF Micro-Force Sensor." Applied Mechanics and Materials 599-601 (August 2014): 1135–38. http://dx.doi.org/10.4028/www.scientific.net/amm.599-601.1135.

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At present, sub-micro-Newton (sub-μN) micro-force in micro-assembly and micro-manipulation is not able to be measured reliably. The piezoelectric micro-force sensors offer a lot of advantages for MEMS applications such as low power dissipation, high sensitivity, and easily integrated with piezoelectric micro-actuators. In spite of many advantages above, the research efforts are relatively limited compared to piezoresistive micro-force sensors. In this paper, Sensitive component is polyvinylidene fluoride (PVDF) and the research object is micro-force sensor based on PVDF film. Moreover, the model of micro-force and sensor’s output voltage is built up, signal processing circuit is designed, and a novel calibration method of micro-force sensor is designed to reliably measure force in the range of sub-μN. The experimental results show the PVDF sensor is designed in this paper with sub-μN resolution.

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11

Xu, Sheng, Rui Zhang, Junpeng Cui, Tao Liu, Xiuli Sui, Meng Han, Fu Zheng, and Xiaoguang Hu. "Surface Acoustic Wave DMMP Gas Sensor with a Porous Graphene/PVDF Molecularly Imprinted Sensing Membrane." Micromachines 12, no. 5 (May 12, 2021): 552. http://dx.doi.org/10.3390/mi12050552.

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In this paper, surface acoustic wave (SAW) sensors containing porous graphene/PVDF (polyvinylidene fluoride) molecularly imprinted sensitive membrane for DMMP gas detection were investigated. A 433 MHz ST-cut quartz SAW resonator was used to convert gas concentration changes into frequency shifts by the sensors. The porous graphene/PVDF film was fabricated on the sensor’s surface by using the tape-casting method. DMMP molecules were adsorbed on the porous structure sensing film prepared by the 2-step method to achieve the specific recognition effect. The sensitivity of the sensor could reach −1.407 kHz·ppm−1. The response time and recovery time of the SAW sensor with porous graphene/PVDF sensing membrane were about 4.5 s and 5.8 s at the concentration of 10 ppm, respectively. The sensor has good anti-interference ability to most gases in the air.

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Grzechnik, Andrzej, and Karen Friese. "Fluorides containing lanthanides and yttrium at extreme conditions." Acta Crystallographica Section A Foundations and Advances 70, a1 (August 5, 2014): C55. http://dx.doi.org/10.1107/s2053273314099446.

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We are interested in crystal structures and stabilities of fluoride materials containing lanthanides and yttrium that are related to the CaF2 structure. These compounds are laser hosts and luminescent materials, oxygen sensors as well as components of solar cells. They exhibit various schemes of (dis)ordering of cations and anions in fluorite superstructures and anion-excess fluorites. In the last few years, we have performed a series of studies on the bulk AMF4 and MF3 materials (A = Li, Na, K; M = Y, lanthanide) at different pressure-temperature conditions. Among them, ordered LiYF4 is a commercial host for solid state lasers, while partially ordered NaYF4 doped with lanthanides is the most efficient material for green and blue up-conversion known to date. In the system KF–YF3, we have studied not only KYF4 [1] but also KY3F10, which is an anion-excess 2×2×2 superstructure of fluorite at atmospheric conditions. At high temperatures and high pressures, it converts to another fluorite superstructure with disordered fluorine atoms. The pressure-induced LaF3 post-tysonite structure is another example of the anion-excess fluorite [2]. Our work on the fluorite-related materials at extreme conditions provides information on their structural instabilities that could further be used to better understand and control their materials properties. For instance, we demonstrated that the NaMF4 up-converters are unstable and that the ordering of the cations and vacancies in their structure is a slow process [3]. Consequently, the order–disorder transformations have a profound influence over the luminescent properties of these materials when doped.

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13

Ying, Sun, Xin Nie, Yuhan Zhou, Rui Cao, Yonghua Yu, Hongping Tian, Xiangqun Qian, and Jianping Wang. "Optimum Design of Impact Sensors With Array Structure Polyvinylidene Fluoride (PVDF) Films." Journal of the ASABE 65, no. 5 (2022): 937–47. http://dx.doi.org/10.13031/ja.14494.

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HighlightsThe impact sensors protected by shells and integrated with process circuits were proposed.Simulations and collision tests were performed to optimize the structure of the sensor.Accessories that can improve sensors’ detection accuracy were proposed.Multi-grain impact tests in a laboratory showed the RMSEs of two sensors were less than 1.67%.Abstract. Impact sensors are widely used to detect grain loss in harvesters, and the impact sensors with array structure polyvinylidene fluoride (PVDF) films have been proven to significantly increase the detection efficiency. However, uneven sensitivity and clutters from non-impacted sensitive units seriously affect the detection accuracy. This article proposes a protective shell for the impact sensors with array structure PVDF films. To improve the performance of this kind of sensor, we optimized the structure through finite element simulations and particle impact tests. The vibration modes under three pasting methods of sensitive units were analyzed. The relationship between the hardness of the elastic layer and response performances was investigated. To suppress the clutters, a method of splitting the elastic layer was proposed. Then, we manufactured two optimized impact sensors with one layer and two crossed layers of PVDF films and tested their performances. The results demonstrated that the sensitivities of the gaps between the PVDF films are poor. But when excluding the gaps’ data, the two sensors can meet the detection requirement. Accessories were proposed based on that characteristic to prevent particles from colliding with the gaps. After assembling the accessory, multi-grain impact tests showed that the root-mean-square errors (RMSEs) of the impact sensors with one layer and two crossed layers of PVDF films were 1.67% and 1.63%, respectively. Keywords: Grain loss detection, Particle impact test, Protective shell, Sensor accessory, Structure optimization.

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Moritz, W., L. Bartholomäus, U. Roth, V. Filippov, A. Vasiliev, and A. Terentjev. "Semiconductor sensors for the detection of fluorocarbons, fluorine and hydrogen fluoride." Analytica Chimica Acta 393, no. 1-3 (June 1999): 49–57. http://dx.doi.org/10.1016/s0003-2670(99)00339-6.

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15

Lee, Young Sup. "A New Position Sensor Using a Triangularly Shaped Piezoelectric PVDF Film." Key Engineering Materials 297-300 (November 2005): 2115–21. http://dx.doi.org/10.4028/www.scientific.net/kem.297-300.2115.

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This paper describes a novel tip position sensor for a cantilever beam made of a triangularly shaped distributed piezoelectric PVDF (polyvinylidene fluoride) film. Due to the boundary condition of the cantilever beam and the spatial sensitivity function of the distributed PVDF sensor, the charge output of the PVDF sensor can be shown to be proportional to the tip position of the beam. Experimental result using the triangular PVDF sensor were compared with those using two commercially available position sensors: an inductive sensor and an accelerometer (after double integration). The resonance frequencies of the test beam, measured using the PVDF sensor, matched well with those measured with the two commercial sensors and the PVDF sensor also showed good coherence over wide frequency range, whereas the inductive sensor became poor above 300Hz. However, the measured response of the PVDF sensor showed a bit larger magnitude compared with the two commercial sensors at higher frequencies. The triangular PVDF sensor have a number of advantages over conventional position sensors and could be used as tip position sensors.

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Hughes, W. Jack. "Underwater polyvinylidene fluoride (PVDF) acoustic sensors." Journal of the Acoustical Society of America 91, no. 4 (April 1992): 2335. http://dx.doi.org/10.1121/1.403503.

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17

Moritz, Werner, and Lothar Müller. "Mechanistic study of fluoride ion sensors." Analyst 116, no. 6 (1991): 589–93. http://dx.doi.org/10.1039/an9911600589.

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D’Andrea, Alessia, Giuseppe Pomarico, Sara Nardis, Roberto Paolesse, Corrado Di Natale, and Larisa Lvova. "Chemical traffic light: A self-calibrating naked-eye sensor for fluoride." Journal of Porphyrins and Phthalocyanines 23, no. 01n02 (January 2019): 117–24. http://dx.doi.org/10.1142/s1088424619500159.

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We report a low-cost sensing platform for effective naked-eye detection of fluoride ion in aqueous media. The sensor is based on silicon complex of 5,10,15-tritolylcorrole (SiTTCorr) deposited on paper support and designed in a particular way that permits it to perform in a unique sensing event an internal sensor self-calibration and subsequent analysis of fluoride ion in a concentration range from 20 [Formula: see text]g/L to 200 mg/L with a LOD 9 [Formula: see text]g/L, much lower than the WHO guideline value of 1.5 mg/L for fluoride in drinking water. The influence of tetradodecylammonium chloride (TDACl) anion exchanger addition to the performance of SiTTCorr-based sensors was studied and the sensor with optimal ionophore: exchanger [Formula: see text] 2:1 ratio demonstrated the highest sensitivity. The evident color variation of SiTTCorr-based optode from dark pink to intense green occurred upon addition of increasing concentrations of fluoride. A smartphone application equipped with home-written color intensity analysis software as a detector of developed sensor output permitted fluoride content quantification in bottled water and toothpaste samples. Moreover, since at the quantification step the SiTTCorr color variation was significant for the red component of visible light and increase of fluoride content evidently changed this color from red to yellow and then to green, the developed optode was compared to a kind of chemical traffic light, able to detect the presence of fluoride in permitted, borderline or dangerous concentrations, respectively.

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Cui, Hongyu, Weiqiang Peng, Xin Xu, and Ming Hong. "A damage identification method for a thin plate structure based on PVDF sensors and strain mode." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 233, no. 14 (March 21, 2019): 4881–95. http://dx.doi.org/10.1177/0954406219838579.

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Damage identification methods for engineering structures based on vibration parameters have the advantages of easy detection and high precision; however, structural strain information is more sensitive to structural damage than displacement information. Traditional resistance strain sensors have low accuracy and poor stability when measuring structural strains. Therefore, this paper uses a highly sensitive polyvinylidene fluoride dynamic strain sensor to identify structural damage in a thin plate. The polyvinylidene fluoride sensor is used to obtain structural strain response information, and structural modal parameters are identified using operational modal identification methods based on the natural excitation technique and the eigensystem realization algorithm. This paper uses a damage index based on mode shape and flexibility. A new damage index based on the LU decomposition of the flexibility matrix is used to identify the damage of the thin plate structure. The effectiveness of the modal identification methods and the new damage index is validated via an elastic thin plate experiment. The results show that the modal identification method and the new damage index proposed in this paper can identify damage in a thin plate structure. Sensor comparison experiments also show that compared with a resistance strain sensor, the polyvinylidene fluoride sensor has higher damage sensitivity, better damage recognition and the ability to recognize farther from the sensor.

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Dey, Sandeep Kumar, and Christoph Janiak. "The curious case of salicylidene-based fluoride sensors: chemosensors or chemodosimeters or none of them." RSC Advances 10, no. 25 (2020): 14689–93. http://dx.doi.org/10.1039/d0ra02293d.

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Du, Jingtao, and Qi Chen. "Design of distributed piezoelectric modal sensor for a rotating beam with elastic boundary restraints." Journal of Vibration and Control 26, no. 23-24 (April 27, 2020): 2340–54. http://dx.doi.org/10.1177/1077546320923460.

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As an advanced sensing technique, modal sensors have been attracting a lot of research interest in modal filtering and active control fields. Most of the existing investigations are mainly focused on the static structure. In contrast, there is little effort made for its rotating counterpart, which is frequently encountered in various power machineries. Motivated by such limitation, a unified framework for the distributed piezoelectric modal sensor design of rotating beams with elastic boundary restraints is proposed using polyvinylidene fluoride piezoelectric integral equation and the second-order structural modal functions. A boundary smoothed Fourier series is used to obtain the modal information of rotating beams by solving the differential governing equation and elastic boundary conditions, simultaneously. Modal sensor shape of rotating beams can be determined for any boundary condition by simply setting the elastic restraining coefficients accordingly, instead of reformulating the equation or rewriting the codes like other approach usually does. Numerical examples are presented to demonstrate the correctness and effectiveness of the proposed framework. Modal sensitivity coefficient and charge output frequency response under external excitation are calculated to demonstrate the performance of the designed piezoelectric modal sensors. Influence of rotation speed and boundary restraining stiffness on the modal sensing accuracy of the shaped polyvinylidene fluoride sensor is analyzed and addressed. To our best knowledge, this work represents the first time that an analytical solution for the distributed piezoelectric modal sensor design of a rotating beam with general boundary conditions is derived, which can shed some new lights on further design and implementation of polyvinylidene fluoride modal sensing technique for rotating structures.

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Yang, Ziyu, Huihui Zhang, Junjie Xu, Renzhi Ma, Takayoshi Sasaki, Yu-Jia Zeng, Shuangchen Ruan, and Yanglong Hou. "Anisotropic fluoride nanocrystals modulated by facet-specific passivation and their disordered surfaces." National Science Review 7, no. 5 (March 13, 2020): 841–48. http://dx.doi.org/10.1093/nsr/nwaa042.

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Abstract Rutile-type fluorides have been proven to be active components in the context of emerging antiferr-omagnetic devices. However, controlled synthesis of low-dimensional, in particular two-dimensional (2D), fluorides in a predictable and deterministic manner remains unrealized because of a lack of efficient anisotropic control, which impedes their further development in reduced dimensions. We report here that altered passivation of {110} growing facets can direct the synthesis of rutile-type fluoride nanocrystals into well-defined zero-dimensional (0D) particulates, one-dimensional (1D) rods and 2D sheets in a colloidal approach. The obtained nanocrystals show positive exchange bias and enhanced magnetic transition temperature from the coexistence of long-range antiferromagnetic order and disordered surface spins, making them strong alternatives for flexible magnetic devices and sensors.

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Lee, Kwan Hee, Ho-Yong Lee, Dong Hoon Lee, and Jong-In Hong. "Fluoride-selective chromogenic sensors based on azophenol." Tetrahedron Letters 42, no. 32 (August 2001): 5447–49. http://dx.doi.org/10.1016/s0040-4039(01)01011-5.

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Zhao, Ping, Jianbing Jiang, Bing Leng, and He Tian. "Polymer Fluoride Sensors Synthesized by RAFT Polymerization." Macromolecular Rapid Communications 30, no. 20 (July 15, 2009): 1715–18. http://dx.doi.org/10.1002/marc.200900318.

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Singh, Rahul Kumar, Sun Woh Lye, and Jianmin Miao. "PVDF Nanofiber Sensor for Vibration Measurement in a String." Sensors 19, no. 17 (August 29, 2019): 3739. http://dx.doi.org/10.3390/s19173739.

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Flexible, self-powered and miniaturized sensors are extensively used in the areas of sports, soft robotics, health care and communication devices. Measurement of vibration is important for determining the mechanical properties of a structure, specifically the string tension in strings. In this work, a flexible, lightweight and self-powered sensor is developed and attached to a string to measure vibrations characteristics in strings. Electrospun poly(vinylidene) fluoride (PVDF) nanofibers are deposited on a flexible liquid crystal polymer (LCP) substrate for the development of the sensor. The electrospinning process is optimized for different needle sizes (0.34–0.84 mm) and flow rates (0.6–3 mL/h). The characterization of the sensor is done in a cantilever configuration and the test results indicate the sensor’s capability to measure the frequency and strain in the required range. The comparison of the results from the developed PVDF sensor and a commercial Laser Displacement Sensor (LDS) showed good resemblance (±0.2%) and a linear voltage profile (0.2 mV/με). The sensor, upon attachment to a racket string, is able to measure single impacts and sinusoidal vibrations. The repeatability of the results on the measurement of vibrations produced by an impact hammer and a mini shaker demonstrate an exciting new application for piezoelectric sensors.

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Ikei, Alec, James Wissman, Kaushik Sampath, Gregory Yesner, and Syed N. Qadri. "Tunable In Situ 3D-Printed PVDF-TrFE Piezoelectric Arrays." Sensors 21, no. 15 (July 24, 2021): 5032. http://dx.doi.org/10.3390/s21155032.

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In the functional 3D-printing field, poly(vinylidene fluoride-co-trifluoroethylene) (PVDF-TrFE) has been shown to be a more promising choice of material over polyvinylidene fluoride (PVDF), due to its ability to be poled to a high level of piezoelectric performance without a large mechanical strain ratio. In this work, a novel presentation of in situ 3D printing and poling of PVDF-TrFE is shown with a d33 performance of up to 18 pC N−1, more than an order of magnitude larger than previously reported in situ poled polymer piezoelectrics. This finding paves the way forward for pressure sensors with much higher sensitivity and accuracy. In addition, the ability of in situ pole sensors to demonstrate different performance levels is shown in a fully 3D-printed five-element sensor array, accelerating and increasing the design space for complex sensing arrays. The in situ poled sample performance was compared to the performance of samples prepared through an ex situ corona poling process.

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Fares, Hoda, Yahya Abbass, Maurizio Valle, and Lucia Seminara. "Validation of Screen-Printed Electronic Skin Based on Piezoelectric Polymer Sensors." Sensors 20, no. 4 (February 20, 2020): 1160. http://dx.doi.org/10.3390/s20041160.

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This paper proposes a validation method of the fabrication technology of a screen-printed electronic skin based on polyvinylidene fluoride-trifluoroethylene P(VDF-TrFE) piezoelectric polymer sensors. This required researchers to insure, through non-direct sensor characterization, that printed sensors were working as expected. For that, we adapted an existing model to non-destructively extract sensor behavior in pure compression (i.e., the d33 piezocoefficient) by indentation tests over the skin surface. Different skin patches, designed to sensorize a glove and a prosthetic hand (11 skin patches, 104 sensors), have been tested. Reproducibility of the sensor response and its dependence upon sensor position on the fabrication substrate were examined, highlighting the drawbacks of employing large A3-sized substrates. The average value of d33 for all sensors was measured at incremental preloads (1–3 N). A systematic decrease has been checked for patches located at positions not affected by substrate shrinkage. In turn, sensor reproducibility and d33 adherence to literature values validated the e-skin fabrication technology. To extend the predictable behavior to all skin patches and thus increase the number of working sensors, the size of the fabrication substrate is to be decreased in future skin fabrication. The tests also demonstrated the efficiency of the proposed method to characterize embedded sensors which are no more accessible for direct validation.

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Aziz, Shahid, Bhandari Krishna Singh, and Dong Won Jung. "Flexible Temperature Sensor Based on Binary Polymer Composite Thin Film." Key Engineering Materials 927 (July 29, 2022): 172–77. http://dx.doi.org/10.4028/p-b898zj.

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A high performance flexible temperature sensor for environmental and health monitoring has been fabricated using various combinations of composite blend of poly vinylidene fluoride / poly (3,4-ethylenedioxythiophene)-poly (styrenesulfonate) (PVDF/PEDOT:PSS). The response curves and working principle were investigated and sensors were then fabricated to achieve highly linear and stable response for a wide range of temperature sensing (25°C to 120°C). The film was fabricated on flexible polyethylene terephthalate (PET) substrate using spin coating. The copper electrodes were fabricated using copper tape. The sensors showed stable and close to linear response of impedance change by varying temperature in the range 25°C to 120°C. The resistance of the sensors changed from ~70MΩ to ~52MΩ for the temperature change in the range 25°C to 120°C. The sensors are aimed to replace low performance, complex and expensive sensors in the market for environmental and health monitoring applications.

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Lu, Yifan, Marco Amabili, Jian Wang, Fei Yang, Honghao Yue, Ye Xu, and Hornsen Tzou. "Active vibration control of a polyvinylidene fluoride laminated membrane plate mirror." Journal of Vibration and Control 25, no. 19-20 (July 11, 2019): 2611–26. http://dx.doi.org/10.1177/1077546319862445.

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Lightweight optical mirrors usually play key roles in aerospace and optical structural systems applied to space telescopes, radars, solar collectors, communication antennas, etc. Due to their high flexibility and low damping properties, external excitations such as orbital maneuver may induce unexpected oscillations and thus reduce their working performance. Active vibration control is therefore essential for the lightweight optical mirror systems. In this spirit, a lightweight mirror structronic system with a linear quadratic optimal controller is presented. The mirror is modeled as a membrane plate with pretension and distributed polyvinylidene fluoride sensors and actuators. The sensing sensitivity of the piezoelectric (PVDF) sensors and the modal actuation factor of the PVDF actuators are derived. The state-space equations are established and the feedback control gains between sensing and control signals are obtained. Sensor and actuator of different shape, size, and position are employed to actively control the first four natural modes of the mirror. The influences of mode order, pretension, and the two weighting factors Q and R on the control performance are also investigated. Analytical results in this paper could guide the design and layout of the PZT sensor and actuator on lightweight membrane plate mirrors.

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Sanati, Mehdi, Allen Sandwell, Hamid Mostaghimi, and Simon Park. "Development of Nanocomposite-Based Strain Sensor with Piezoelectric and Piezoresistive Properties." Sensors 18, no. 11 (November 6, 2018): 3789. http://dx.doi.org/10.3390/s18113789.

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Sensors provide aninterface between mechanical systems and the physical world. With the move towardsIndustry 4.0 and cyber-physical systems, demands for cost-effective sensors are rapidly increasing. Conventional sensors used for monitoring manufacturing processes are often bulky and need complex processes. In this study, a novel high-sensitive nanocomposite-based sensor is developed for measuring strain. The developed sensor is comprised of polyvinylidene fluoride (PVDF) as a piezoelectric polymer matrix, and embedded carbon nanotube (CNT) nanoparticles creating a conductive network. Exhibiting both piezoelectric and piezoresistive properties, the developed sensors are capable of strain measurement over a wide frequency band, including static and dynamic measurements. The piezoresistive and piezoelectric properties are fused to improve the overall sensitivity and frequency bandwidth of the sensor. To simulate the sensor, a 3D random walk model and a 2D finite element (FE) model are used to predict the electrical resistivity and the piezoelectric characteristics of the sensor, respectively. The developed models are verified with the experimental results. The developed nanocomposite sensors were employed for strain measurement of a cantilever beam under static load, impulse excitation, free and forced vibrations, collecting both piezoelectric and piezoresistive properties measurements. The obtained signals were fused and compared with those of a reference sensor. The results show that the sensor is capable of strain measurement in the range of 0–10 kHz, indicating its effectiveness at measuring both static and high frequency signals which is an important feature of the sensor.

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Farhangdoust, Saman, Gary Georgeson, and Jeong-Beom Ihn. "MetaMembranes for the Sensitivity Enhancement of Wearable Piezoelectric MetaSensors." Sensors 22, no. 5 (March 1, 2022): 1909. http://dx.doi.org/10.3390/s22051909.

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The low stretchability of plain membranes restricts the sensitivity of conventional diaphragm-based pressure and inflatable piezoelectric sensors. Using theoretical and computational tools, we characterized current limitations and explored metamaterial-inspired membranes (MetaMems) to resolve these issues. This paper develops two MetaMem pressure sensors (MPSs) to enrich the sensitivity and stretchability of the conventional sensors. Two auxetic hexagonal and kirigami honeycombs are proposed to create a negative Poisson’s ratio (NPR) in the MetaMems which enables them to expand the piezo-element of sensors in both longitudinal and transverse directions much better, and consequently provides the MPSs’ diaphragm a higher capability for flexural deformation. Polyvinylidene fluoride (PVDF) and polycarbonate (PC) are considered as the preferable materials for the piezo-element and MetaMem, respectively. A finite element analysis was conducted to investigate the stretchability behavior of the MetaMems and study its effect on the PVDF’s polarization and sensor sensitivity. The results obtained from theoretical analysis and numerical simulations demonstrate that the proposed MetaMems enhance the sensitivity of pressure sensors up to 3.8 times more than an equivalent conventional sensor with a plain membrane. This paper introduces a new class of flexible MetaMems to advance wearable piezoelectric metasensor technologies.

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González-Ruiz, Víctor, Ángel Cores, M. Mar Caja, Vellaisamy Sridharan, Mercedes Villacampa, M. Antonia Martín, Ana I. Olives, and J. Carlos Menéndez. "Fluorescence Sensors Based on Hydroxycarbazole for the Determination of Neurodegeneration-Related Halide Anions." Biosensors 12, no. 3 (March 14, 2022): 175. http://dx.doi.org/10.3390/bios12030175.

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The environmental presence of anions of natural origin or anthropogenic origin is gradually increasing. As a tool to tackle this problem, carbazole derivatives are an attractive gateway to the development of luminescent chemosensors. Considering the different mechanisms proposed for anion recognition, the fluorescence properties and anion-binding response of several newly synthesised carbazole derivatives were studied. Potential anion sensors were designed so that they combined the native fluorescence of carbazole with the presence of hydrogen bonding donor groups in critical positions for anion recognition. These compounds were synthesised by a feasible and non-expensive procedure using palladium-promoted cyclodehydrogenation of suitable diarylamine under microwave irradiation. In comparison to the other carbazole derivatives studied, 1-hydroxycarbazole proved to be useful as a fluorescent sensor for anions, as it was able to sensitively recognise fluoride and chloride anions by establishing hydrogen bond interactions through the hydrogen atoms on the pyrrolic nitrogen and the hydroxy group. Solvent effects and excited-state proton transfer (ESPT) of the carbazole derivatives are described to discard the role of the anions as Brönsted bases on the observed fluorescence behaviour of the sensors. The anion–sensor interaction was confirmed by 1H-NMR. Molecular modelling was employed to propose a mode of recognition of the sensor in terms of complex stability and interatomic distances. 1-hydroxycarbazole was employed for the quantitation of fluoride and chloride anions in commercially available medicinal spring water and mouthwash samples.

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Raman, Reshmi, Oscar A. Jaramillo, and Marina E. Rincón. "The Effect of Anodization Time on the Properties of TiO2 Nanotube Humidity Sensors." MRS Proceedings 1479 (2012): 83–88. http://dx.doi.org/10.1557/opl.2012.1602.

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ABSTRACTIn this paper, the effect of anodization time on the properties of TiO2 nanotube humidity sensors is reported. TiO2 nanotube arrays were grown by anodization of Ti foil using diethylene glycol and ammonium fluoride. Highly ordered TiO2 nanotube arrays were obtained, with the length of tube increasing from 4 to 20 μm as the time of anodization increases, at the expense of nanotube integrity. Humidity sensors based on TiO2 nanotube arrays were fabricated in impedance mode with ITO as top contact. The results revealed that sensor performance does not correlate with anodization time, regardless of enhanced area, showing an optimum morphology at 4h and 10h. The increase resistivity of the sensors upon water exposure, a donor molecule, is explained by the lack of TiO2 stoichiometry and the fluctuations in the concentration of oxygen vacancies.

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Feng, Lin, Jian Wang, Ye Chen, and Chao Ding. "Detection and Early Warning of Toxic Gases Based on Semiconductor Wireless Sensors." Journal of Sensors 2021 (November 26, 2021): 1–11. http://dx.doi.org/10.1155/2021/6988676.

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This paper studies a semiconductor wireless sensor system, which is composed of a semiconductor wireless sensor sampling circuit, gas-sensitive signal alarm and wireless transmitting circuit, and wireless radio frequency signal receiving circuit. The system is suitable for wireless monitoring of hydrogen fluoride gas in chemical plants. The hydrogen fluoride gas sensor is designed, integrated, and classified according to the polarity and size of the sensor output signal. The signal processing circuit of the sensor output signal is made with an integrated design. This paper developed a simulation experimental system for the wireless monitoring network characteristics of toxic hydrogen fluoride gas and completed the monitoring system’s sensor characteristic calibration and accuracy comparison simulation experiment, the communication distance test experiment of the communication system, and the research experiment on the influence of environmental humidity on the sensor characteristics of the monitoring system. In terms of software, the workflow of network nodes has been optimized. Since the structure of the wireless sensor network is not exactly the same in different application fields, the toxic gas monitoring system based on wireless sensor networks must focus on extending the network’s life cycle. Without affecting the normal operation of the system, distributed compressed sensing can greatly extend the service life of the system. Therefore, this subject combines the compressed sensing technology developed in recent years with the air monitoring system for the processing of transmission data, in order to achieve the purpose of further reducing the energy consumption of the system. The simulation experiment demonstrated that the lmF neural network combined with gas sensor array technology can realize qualitative identification, quantitative analysis of single gas, and quantitative analysis of mixed combustible gas. The research work in this area also provides a new way to further combine the miniature hydrogen fluoride gas sensor unit with sensor technology, integrate the hydrogen fluoride gas sensor unit and the electronic tag, and expand the wireless application of the gas sensor.

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Christof, Hans, Lena Müller, Simon Küppers, Paul Hofmann, Elisabeth Giebel, Sabine Frick, Markus Gabler, and Götz T. Gresser. "Integration Methods of Sensors in FRP Components." Materials Science Forum 825-826 (July 2015): 586–93. http://dx.doi.org/10.4028/www.scientific.net/msf.825-826.586.

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Structural health monitoring is an important research topic in the field of fiber reinforced plastics (FRP). An effective way to detect defects or overloads in these FRP has still not been found. One way to monitor the actual state of FRP components is via integrated sensors. Integrating current standard sensors negatively affects the flux of force. Therefore investigations about integration methods of sensors in FRP components have been made. The integration of an optical fiber sensor into FRP profiles via a pultrusion process was investigated. It could be shown that the pultrusion process is suitable method for the integration of fiber optic sensors for strain measurements. Another investigated sensor principle was the integration of piezoelectric polyvinylidene fluoride (PVDF) fibers via a vacuum assisted process. The PVDF fibers were integrated into 3-point bending specimen and the piezoelectric effect was tested with and without polarization. The investigation showed that it is possible to measure the piezoelectric effect of PVDF fibers integrated into a 3-point bending test specimen. It could also be shown that carbon fibers can be used as textile electrodes for the measurement of the generated charge on the PVDF surface.

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Alshammari, Alhulw H., Zahrah Alqahtani, Faiz Bukhari Mohd Suah, Syaza Atikah Nizar, Alan Dunbar, and Martin Grell. "Low-Cost, High-Sensitivity Detection of Waterborne Al3+ Cations and F− Anions via the Fluorescence Response of a Morin Derivative Dye." Engineering Proceedings 6, no. 1 (May 20, 2021): 29. http://dx.doi.org/10.3390/i3s2021dresden-10166.

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Morin dye is known as a cheap and readily available selective ‘off → on’ fluorescent sensitiser when immobilised in a phase transfer membrane for the detection of Al3+ ions. Here, a morin derivative, NaMSA, which readily dissolves in water with good long-term stability is used in conjunction with a fibre-optic transducer with lock-in detection to detect Al3+ in drinking water below the potability limit. The combination of a water-soluble dye and the fibre-optic transducer require neither membrane preparation nor a fluorescence spectrometer yet still display a high figure of merit. The known ability to recover morin-based Al3+ cation sensors selectively by exposure to fluoride (F−) anions is further developed, enabling a complementary sensing of either fluoride anions, or aluminium cations, using the same dye with a sub-micromolar limit-of-detection for both ions. The sensor performance parameters compare favourably to prior reports on both aqueous aluminium and fluoride ion sensing.

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Zhou, Lili, Xiaohong Zhang, and Shikang Wu. "Fluoride-selective Colorimetric Sensors Based on Hydrazone Functionality." Chemistry Letters 33, no. 7 (July 2004): 850–51. http://dx.doi.org/10.1246/cl.2004.850.

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Godovski, D. Yu, A. A. Vasilev, and E. V. Dorofeev. "Analysis of hydrogen fluoride with SnO2 gas sensors." Sensors and Actuators B: Chemical 19, no. 1-3 (April 1994): 483–85. http://dx.doi.org/10.1016/0925-4005(93)01049-a.

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Devaraj, Soosai, Duraisamy Saravanakumar, and Muthusamy Kandaswamy. "Simple colorimetric fluoride sensors based on nitrophenyl derivatives." Supramolecular Chemistry 21, no. 8 (October 23, 2009): 717–23. http://dx.doi.org/10.1080/10610270902795376.

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40

Pereira, Nélson, Ana Catarina Lima, Vitor Correia, Nikola Peřinka, Senentxu Lanceros-Mendez, and Pedro Martins. "Magnetic Proximity Sensor Based on Magnetoelectric Composites and Printed Coils." Materials 13, no. 7 (April 7, 2020): 1729. http://dx.doi.org/10.3390/ma13071729.

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Magnetic sensors are mandatory in a broad range of applications nowadays, being the increasing interest on such sensors mainly driven by the growing demand of materials required by Industry 4.0 and the Internet of Things concept. Optimized power consumption, reliability, flexibility, versatility, lightweight and low-temperature fabrication are some of the technological requirements in which the scientific community is focusing efforts. Aiming to positively respond to those challenges, this work reports magnetic proximity sensors based on magnetoelectric (ME) polyvinylidene fluoride (PVDF)/Metglas composites and an excitation-printed coil. The proposed magnetic proximity sensor shows a maximum resonant ME coefficient (α) of 50.2 Vcm−1 Oe−1, an AC linear response (R2 = 0.997) and a maximum voltage output of 362 mV, which suggests suitability for proximity-sensing applications in the areas of aerospace, automotive, positioning, machine safety, recreation and advertising panels, among others.

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Li, Qingting, Yanqiong Li, and Wen Zeng. "Preparation and Application of 2D MXene-Based Gas Sensors: A Review." Chemosensors 9, no. 8 (August 14, 2021): 225. http://dx.doi.org/10.3390/chemosensors9080225.

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Since MXene (a two-dimensional material) was discovered in 2011, it has been favored in all aspects due to its rich surface functional groups, large specific surface area, high conductivity, large porosity, rich organic bonds, and high hydrophilicity. In this paper, the preparation of MXene is introduced first. HF etching was the first etching method for MXene; however, HF is corrosive, resulting in the development of the in situ HF method (fluoride + HCl). Due to the harmful effects of fluorine terminal on the performance of MXene, a fluorine-free preparation method was developed. The increase in interlayer spacing brought about by adding an intercalator can affect MXene’s performance. The usual preparation methods render MXene inevitably agglomerate and the resulting yields are insufficient. Many new preparation methods were researched in order to solve the problems of agglomeration and yield. Secondly, the application of MXene-based materials in gas sensors was discussed. MXene is often regarded as a flexible gas sensor, and the detection of ppb-level acetone at room temperature was observed for the first time. After the formation of composite materials, the increasing interlayer spacing and the specific surface area increased the number of active sites of gas adsorption and the gas sensitivity performance improved. Moreover, this paper discusses the gas-sensing mechanism of MXene. The gas-sensing mechanism of metallic MXene is affected by the expansion of the lamellae and will be doped with H2O and oxygen during the etching process in order to become a p-type semiconductor. A p-n heterojunction and a Schottky barrier forms due to combinations with other semiconductors; thus, the gas sensitivities of composite materials are regulated and controlled by them. Although there are only several reports on the application of MXene materials to gas sensors, MXene and its composite materials are expected to become materials that can effectively detect gases at room temperature, especially for the detection of NH3 and VOC gas. Finally, the challenges and opportunities of MXene as a gas sensor are discussed.

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Prigyai, Nicha, Supphachok Chanmungkalakul, Sutthiroj Thanyalax, Mongkol Sukwattanasinitt, and Vuthichai Ervithayasuporn. "Cyclic siloxanes conjugated with fluorescent aromatic compounds as fluoride sensors." Materials Advances 1, no. 9 (2020): 3358–68. http://dx.doi.org/10.1039/d0ma00476f.

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Yang, Xiaolong, Zhao Feng, Jingshuang Dang, Yuanhui Sun, Guijiang Zhou, and Wai-Yeung Wong. "High performance solution-processed organic yellow light-emitting devices and fluoride ion sensors based on a versatile phosphorescent Ir(iii) complex." Materials Chemistry Frontiers 3, no. 3 (2019): 376–84. http://dx.doi.org/10.1039/c8qm00548f.

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Wang, Xiao, Baobao Qiao, Shaobo Tan, Weiwei Zhu, and Zhicheng Zhang. "Tuning the ferroelectric phase transition of PVDF by uniaxially stretching crosslinked PVDF films with CFCH bonds." Journal of Materials Chemistry C 8, no. 33 (2020): 11426–40. http://dx.doi.org/10.1039/d0tc02559c.

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Poly(vinylidene fluoride) (PVDF) based relaxor ferroelectric polymers show great potential for applications in transducers, sensors and artificial muscles for their excellent electrostrictive properties.

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Jaworska, Ewa, Fabrizio Caroleo, Corrado Di Natale, Krzysztof Maksymiuk, Roberto Paolesse, and Agata Michalska. "Si-corrole-based fluoride fluorometric turn-on sensor." Journal of Porphyrins and Phthalocyanines 24, no. 05n07 (May 2020): 929–37. http://dx.doi.org/10.1142/s1088424620500029.

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We present here a new type of fluoride ion optode, constituted by a highly lipophilic PVDF porous membrane modified with a liquid receptor layer containing the emission-active Si corrole F[Formula: see text] selective ionophore. For the optimized composition of the receptor layer, in acidic solutions an increase of Si-corrole emission was observed by increasing fluoride ion concentration, a behavior different from most porphyrinoid-based optical sensors. An observed linear dependence of the Si corrole emission intensity (read at 635 nm) was within the range 10[Formula: see text] to 10[Formula: see text] M of fluoride ions.

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Liu, Yinhong, Yuhan Wei, Yongshuang Bian, Shengjiao He, Xin Wang, Xin Liu, Chenglei Li, et al. "A 2-(benzo[d]thiazol-2-yl)phenol based on conjugated polymer: Highly selective colorimetric fluorescent chemosensor for F-depending on Si–O bond cleavage reaction." High Performance Polymers 32, no. 3 (July 28, 2019): 344–56. http://dx.doi.org/10.1177/0954008319866003.

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Design and synthesis of highly selective fluorine ion probes become particularly important owing to the specific role of fluorine ion in chemical and biomedical progresses. As a new-type of fluorescent material, conjugated polymers with unique photometric properties have been widely researched by scientists in the field of the fluorescence sensors. In this study, the polymer PBTPV-OSi containing benzothiazole moiety is synthesized via palladium-catalyzed Heck coupling reaction. This polymer not only exhibits good solubility in organic solvents but also shows high selectivity for fluorine ion detection in comparison to other anions. Upon addition of F− to PBTPV-OSi solution, Si–O cleavage of PBTPV-OSi leads to the fluorescence quenching of the polymer in tetrahydrofuran dramatically, and the detection limit is 8 × 10−6 mol/L. Moreover, besides detecting fluorine ion from organic phase, the probe can also effectively detect potassium fluoride from inorganic phase. More importantly, a naked-eye detectable chromogenic and fluorogenic dual response to fluorine ion (F−) can be visibly noted and the detection process of fluorine ion is relatively fast.

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Sedlák, Petr, Petr Kuberský, Adam Gajdoš, Jiří Majzner, Vlasta Sedláková, Robert Macků, and Vladimír Holcman. "Effect of the Different Crystallinity of Ionic Liquid Based Solid Polymer Electrolyte on the Performance of Amperometric Gas Sensor." Engineering Proceedings 2, no. 1 (November 14, 2020): 37. http://dx.doi.org/10.3390/ecsa-7-08166.

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Solid polymer electrolytes (SPE) based on ionic liquid, poly-(vinylidene fluoride) and solvent N-methyl-pyrrolidone represent an effective component in electrochemical sensors. The advantage lies in their composition, which offers an opportunity to prepare SPE layers with a different porosity and microstructure. The study shows how the SPEs of different crystallinities affect the performance of an amperometric gas sensor from the point of view of current response (sensitivity), limit of detection and current fluctuations. The morphology of SPE has an impact not only on its conductivity but also on sensor sensitivity due to the morphology of the interface SPE/working electrode (WE).

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Rozema, Randall, Brian Zellers, Koorosh Naghshineh, and Marcellin Zahui. "Development of a PVDF Sensor for the Measurement of the Acoustic Local Volume Displacement of Vibrating Beams." Journal of Vibration and Acoustics 126, no. 3 (July 1, 2004): 352–58. http://dx.doi.org/10.1115/1.1760556.

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One method of reduction of radiated sound from vibrating structures is to reduce the surface volume velocity. At low frequencies, the volume velocity (or volume displacement) of a vibrating surface is directly related to the sound power emitted from that surface. Recent methods used for sensing surface volume displacement entail the use of a surface mounted strip of shaped polyvinylidene fluoride (PVDF) that spans the entire length of the structure. This paper shows that the volume displacement of a vibrating beam can be measured through the use of a set of localized PVDF sensors each spanning only an area of interest. Summation of the volume displacements measured by these sensors would yield the total beam volume displacement. In this application it was shown that two point sensors are required in addition to the distributed PVDF sensor to achieve such measurements. To examine the localized sensors developed, four beams with different end conditions (fixed-fixed, fixed-free, fixed-simply supported, and simply supported-simply supported) were constructed. In designing the localized surface sensors, the sensor shapes necessary to measure a localized area of interest were determined, these sensors were constructed, and subsequently tested using a fixture constructed for this specific purpose. Finally, a comparison between the measured values obtained using these combined PVDF/Accelerometer sensors were compared to those obtained using an array of accelerometers was performed to determine the accuracy of these sensors. It was discovered that the localized sensors developed were sufficiently accurate for sensing the volume displacement of the vibrating beam within a 0–1600 Hz frequency range. Possible sources of error are discussed in the text.

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Black, Christopher B., Bruno Andrioletti, Andrew C. Try, Cristina Ruiperez, and Jonathan L. Sessler. "Dipyrrolylquinoxalines: Efficient Sensors for Fluoride Anion in Organic Solution." Journal of the American Chemical Society 121, no. 44 (November 1999): 10438–39. http://dx.doi.org/10.1021/ja992579a.

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Kiprianov, A. A., N. M. Pankratova, and I. A. Ponomarev. "Potentiometric pH sensors for measurements in fluoride-containing solutions." Russian Journal of Applied Chemistry 84, no. 11 (November 2011): 1883–89. http://dx.doi.org/10.1134/s1070427211110085.

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Journal articles on the topic 'Fluoride Sensors'

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