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Highlights Continuous piezoelectric BaTi0.88Sn0.12O3 (BTS) films were deposited on glass fiber fabrics successfully. Superflexible, highly sensitive self-powered piezoelectric sensors were fabricated based on polarization-free BTS. Low curie temperature would be a benefit for flexible piezoelectric sensors because small alterations of force will trigger large changes in polarization. The superflexible sensors are highly desirable for wearable devices to detect human motion. Supplementary Information The online version contains supplementary material available at 10.1007/s40820-021-00649-9., For traditional piezoelectric sensors based on poled ceramics, a low curie temperature (Tc) is a fatal flaw due to the depolarization phenomenon. However, in this study, we find the low Tc would be a benefit for flexible piezoelectric sensors because small alterations of force trigger large changes in polarization. BaTi0.88Sn0.12O3 (BTS) with high piezoelectric coefficient and low Tc close to human body temperature is taken as an example for materials of this kind. Continuous piezoelectric BTS films were deposited on the flexible glass fiber fabrics (GFF), self-powered sensors based on the ultra-thin, superflexible, and polarization-free BTS-GFF/PVDF composite piezoelectric films are used for human motion sensing. In the low force region (1–9 N), the sensors have the outstanding performance with voltage sensitivity of 1.23 V N−1 and current sensitivity of 41.0 nA N−1. The BTS-GFF/PVDF sensors can be used to detect the tiny forces of falling water drops, finger joint motion, tiny surface deformation, and fatigue driving with high sensitivity. This work provides a new paradigm for the preparation of superflexible, highly sensitive and wearable self-powered piezoelectric sensors, and this kind of sensors will have a broad application prospect in the fields of medical rehabilitation, human motion monitoring, and intelligent robot. Supplementary Information The online version contains supplementary material available at 10.1007/s40820-021-00649-9.

In this paper, we describe and present a Virtual Instrument, a tool that allows the determination of the electromechanical, dielectric, and elastic coefficients in polarised ferroelectric ceramic discs (piezoceramics) in the linear range, including all of the losses when the piezoceramics are vibrating in radial mode. There is no evidence in the recent scientific literature of any automatic system conceived and implemented as a Virtual Instrument based on an iterative algorithm issued as an alternative to solve the limitations of the ANSI IEEE 176 standard for the characterisation of piezoelectric coefficients of thin discs in resonant mode. The characterisation of these coefficients is needed for the design of ultrasonic sensors and generators. In 1995, two of the authors of this work, together with other authors, published an iterative procedure that allowed for the automatic determination of the complex constants for lossy piezoelectric materials in radial mode. As described in this work, the procedures involved in using a Virtual Instrument have been improved: the response time for the characterisation of a piezoelectric sample is shorter (approximately 5 s), the accuracy in measurement and, therefore, in the estimates of the coefficients has been increased, the calculation speed has been increased, an intuitive, simple, and friendly user interface has been designed, and tools have been provided for exporting and inspecting the measured and processed data. No Virtual Instrument has been found in the recent scientific literature that has improved on the iterative procedure designed in 1995. This Virtual Instrument is based on the measurement of a unique magnitude, the electrical admittance (Y = G + iB) in the frequency range of interest. After measuring the electrical admittance, estimates of the set of piezoelectric coefficients of the device are obtained. The programming language used in the construction of the Virtual Instrument is LabVIEW 2019®.

The Third Canadian International Composites Conference (CANCOM 2001) From 8/21/2001 To 8/24/2001, available, unclassified, unlimited

Piezoelectric polymers characterized by flexibility are sought for applications in microelectronics, medicine, telecommunications, and everyday devices. The objective of this work was to obtain piezoelectric polymeric composites with a cellular structure and to evaluate their usefulness in practice. Composites based on polyolefins (isotactic-polypropylene and polyethylene) with the addition of aluminosilicate fillers were manufactured by extrusion, and then polarized in a constant electric field at 100 V/&micro, m. The content of mineral fillers up to 10 wt% in the polymer matrix enhances its electric stability and mechanical strength. The value of the piezoelectric coefficient d33 attained ~150 pC/N in the range of lower stresses and ~80 pC/N in the range of higher stresses, i.e., at ~120 kPa. The materials exhibited high durability in time, therefore, they can be used as transducers of mechanical energy of the human motion into electric energy. It was demonstrated that one shoe insert generates an energy of 1.1 mJ after a person walks for 300 s. The miniaturized integrated circuits based on polyolefin composites may be applied for the power supply of portable electronics. Due to their high sensitivity, they can be recommended for measuring the blood pulse.

In order to control the adverse effect of vehicles overloading infrastructure and traffic safety, weight-in-motion (WIM)-related research has drawn growing attention. To address the high cost of current piezoelectric sensors in installation and maintenance, a study on developing a low-cost piezoceramic sensing system is presented in this paper. The proposed system features distributed monitoring and integrated packaging, for calculating vehicle&rsquo, s dynamic load and its wheel position. Results from the laboratory tests show that the total output of the sensing system increases linearly with the increase of the peak load when the loading amplitude is 5&ndash, 25 kN (equivalent to the half-axis load of 20&ndash, 100 kN), when the loading frequency is between 15 Hz and 19 Hz (equivalent to a speed of 17.8&ndash, 23.2 km/h), the total output of the system fluctuates around a value of 1.305 V. Combined with finite-element simulation, the system can locate load lateral position with a resolution of 120 mm. Due to the protection packaging, the peak load transferred to the sensing units is approximately 4.36% of the applied peak load. The study indicates the proposed system can provide a promising low-cost, reliable and practical alternative for current WIM systems.

This study presents a set of experimental and numerical investigations to study the sensitivity of the piezoelectric-based smart interface device to structural damage in a bolted connection. The study aims to identify the proper geometric sizes of smart interfaces for damage detection tasks. First, the fundamentals of the damage monitoring technique via lead zirconate titanate(PZT) interface is briefly described for a bolted connection. Second, a lab-scaled girder connection is selected as the test structure for the experimental investigation. PZT interface prototypes with varying geometric sizes are designed for the test connection. Under the bolt-loosening inflicted in the connection, the impedance responses of the PZT interfaces are analyzed to understand the effect of geometric parameters on the damage sensitivity of the impedance responses. Subsequently, the bolt-loosening detection capabilities of the PZT interfaces are comparatively evaluated for identifying the proper geometric sizes of the devices. Finally, a finite element model of the PZT interface-bolted connection system is established for the numerical investigation. The damage sensitivity of the numerical impedance responses is compared with the experimental results for the verification.

We present the use of piezoelectric disk buzzers, usual in stringed musical instruments to acquire sound as a voltage signal, for experimental modal analysis. These transducers helped in extracting natural frequencies and mode shapes of an aluminium beam and a steel arch in the laboratory. The results are compared with theoretical predictions and experimental values obtained by accelerometers and a laser displacement transducer. High accuracy, small dimensions, low weight, easy usage, and low cost, make piezoelectric pickups an attractive tool for the experimental modal analysis of engineering structures.

The study presented in this paper introduces a new intelligent methodology to mitigate the vibration response of flexible cantilever plates. The use of the piezoelectric sensor/actuator pairs for active control of plates is discussed. An intelligent neural network based controller is designed to control the optimal voltage applied on the piezoelectric patches. The control technique utilizes a neurocontroller along with a Kalman Filter to compute the appropriate actuator command. The neurocontroller is trained based on an algorithm that incorporates a set of emulator neural networks which are also trained to predict the future response of the cantilever plate. Then, the neurocontroller is evaluated by comparing the uncontrolled and controlled responses under several types of dynamic excitations. It is observed that the neurocontroller reduced the vibration response of the flexible cantilever plate significantly; the results demonstrated the success and robustness of the neurocontroller independent of the type and distribution of the excitation force. The financial support for this research was provided by Qatar National Research Fund , QNRF (a member of Qatar Foundation) via the National Priorities Research Program (NPRP) , Project no. NPRP 6-526-2-218 . The statements made herein are solely the responsibility of the authors. Scopus

Conference of 56th Annual Conference of the British Institute of Non-Destructive Testing, NDT 2017 ; Conference Date: 5 September 2017 Through 7 September 2017; Conference Code:130921; International audience; Structural Health Monitoring (SHM) consists in permanently installing sensors onto or into a structure in order to monitor its health without disturbing its regular operating cycle. Guided wave (GW) based SHM relies on the propagation of GWs in plate-like or extruded structures. Because of their high sensitivity to geometrical singularities, GWs are suitable to detect structural flaws. Moreover, because GWs can be generated and measured with lightweight low-energy sensors such as piezoelectric sensors, GWs are often the ideal interrogation mean to detect and locate flaws in a SHM context. Despite the large literature on the use of GW for SHM, no GW-based SHM systems have yet reached a sufficient maturity level to be deployed in large scale industrial applications. The CEA-LIST conducts a substantial number of studies aiming at transferring these technologies from the laboratory towards the industry. This work includes the development of novel simulation tools, the improvement of existing imaging techniques along with their implementation on complex cases, the use of optical fibers to replace or complement piezoelectric sensors and limit the mass of the SHM system and the development of new GW-based techniques. This communication will describe these developments along with the perspectives of this work.

Structural health monitoring (SHM) is a very important area in a wide spectrum of fields and engineering applications. With an SHM system, it is possible to reduce the number of non-necessary inspection tasks, the associated risk and the maintenance cost in a wide range of structures during their lifetime. One of the problems in the detection and classification of damage are the constant changes in the operational and environmental conditions. Small changes of these conditions can be considered by the SHM system as damage even though the structure is healthy. Several applications for monitoring of structures have been developed and reported in the literature, and some of them include temperature compensation techniques. In real applications, however, digital processing technologies have proven their value by: (i) offering a very interesting way to acquire information from the structures under test; (ii) applying methodologies to provide a robust analysis; and (iii) performing a damage identification with a practical useful accuracy. This work shows the implementation of an SHM system based on the use of piezoelectric (PZT) sensors for inspecting a structure subjected to temperature changes. The methodology includes the use of multivariate analysis, sensor data fusion and machine learning approaches. The methodology is tested and evaluated with aluminum and composite structures that are subjected to temperature variations. Results show that damage can be detected and classified in all of the cases in spite of the temperature changes

In the paper, a novel approach for damage localization in reinforced concrete plates, based on the computational analysis of piezoelectric smart aggregates, has been presented. The hybrid approach for damage localization is based on two criteria: wave propagation energy and time of flight. The comprehensive numerical analysis using standard and explicit finite element method has been conducted. In addition, the proposed algorithm of the hybrid method has been coded in MATLAB. The approach has been verified numerically using different square reinforced concrete plate models, considering different number, position and size of damage, as well as different number and position of the piezoelectric smart aggregates. Obtained results confirm the successful application of the novel approach to the damage localization.

A highly sensitive, lead-free, and flexible piezoelectric touch sensor is reported based on composite films of alkaline niobate K0.485Na0.485Li0.03NbO3 (KNLN) powders aligned in a polydimethylsiloxane (PDMS) matrix. KNLN powder is fabricated by solid-state sintering and consists of microcubes. The particles are dispersed in uncured PDMS and oriented by application of an oscillating dielectrophoretic alignment field. The dielectric constant of the composite film is almost independent of the microstructure, while upon alignment the piezoelectric charge coefficient increases more than tenfold up to 17 pC N-1. A quantitative analysis shows that the origin is a reduction of the interparticle distance to under 1.0 μm in the aligned bicontinuous KNLN chains. The temperature stable piezoelectric voltage coefficient exhibits a maximum value of 220 mV m N-1, at a volume fraction of only 10%. This state-of-the-art value outperforms bulk piezoelectric ceramics and composites with randomly dispersed particles, and is comparable to the values reported for the piezoelectric polymers polyvinylidenefluoride and its random copolymer with trifluoroethylene. Optimized composite films are incorporated in flexible piezoelectric touch sensors. The high sensitivity is analyzed and discussed. As the fabrication technology is straightforward and easy to implement, applications are foreseen in flexible electronics such as wireless sensor networks and biodiagnostics.

Impact damage is one of the major concerns in maintenance of structures built from composite materials. For example damages induced by impact in composite overwrapped pressure vessel (COPV) operating in space conditions required an innovative approach for structural health monitoring (SHM) with piezoelectric transducers. Automated impact detection and characterization on structures has been an elusive goal due to the transitory nature of the detectable signals involved. The work describes the development of a real-time electronic system for automated impact detection on a scale model of COPV using piezoelectric transducers connected to a mixed analog-digital electronics.

Continuous monitoring of human physiological signals is critical to managing personal healthcare by early detection of health disorders. Wearable and implantable devices are attracting growing attention as they show great potential for real-time recording of physiological conditions and body motions. Conventional piezoelectric sensors have the advantage of potentially being self-powered, but have limitations due to their intrinsic lack of stretchability. Herein, a kirigami approach to realize a novel stretchable strain sensor is introduced through a network of cut patterns in a piezoelectric thin film, exploiting the anisotropic and local bending that the patterns induce. The resulting pattern simultaneously enhances the electrical performance of the film and its stretchability while retaining the mechanical integrity of the underlying materials. The power output is enhanced from the mechano-electric piezoelectric sensing effect by introducing an intersegment, through-plane, electrode pattern. By additionally integrating wireless electronics, this sensing network could work in an entirely battery-free mode. The kirigami stretchable piezoelectric sensor is demonstrated in cardiac monitoring and wearable body tracking applications. The integrated soft, stretchable, and biocompatible sensor demonstrates excellent in vitro and ex vivo performances and provides insights for the potential use in myriad biomedical and wearable health monitoring applications.

Piezoelectric sensing is of increasing interest for high-temperature applications in aerospace, automotive, power plants and material processing due to its low cost, compact sensor size and simple signal conditioning, in comparison with other high-temperature sensing techniques. This paper presented an overview of high-temperature piezoelectric sensing techniques. Firstly, different types of high-temperature piezoelectric single crystals, electrode materials, and their pros and cons are discussed. Secondly, recent work on high-temperature piezoelectric sensors including accelerometer, surface acoustic wave sensor, ultrasound transducer, acoustic emission sensor, gas sensor, and pressure sensor for temperatures up to 1,250 °C were reviewed. Finally, discussions of existing challenges and future work for high-temperature piezoelectric sensing are presented.

In an effort to improve the situational awareness and obstacle avoidance of marine vehicles, we fabricate, package and characterize (Zr 0.52Ti0.48)O3 thin-film piezoelectric pressure sensor arrays for passive fish-like underwater sensing. We use floating bottom electrode in designing the sensor which made the sensor able to detect very low frequency range (down to 0.1 Hz) in water. The proposed array of sensors is capable of locating underwater objects by transducing the pressure variations generated by the stimulus. The sensors are packaged into an array of 2 × 5 on a flexible liquid crystal polymer substrate patterned with gold interconnects. Experiments in this paper are divided into three main categories. First, in order to evaluate the effect of water on the sensor performance, resonant frequency, and quality factor changes in air and water are investigated theoretically and experimentally. Second, the ability of the array in locating a vibrating sphere (dipole) in water is illustrated through experiments. The sensors demonstrate a high resolution of 3 mms-1 in detecting in detecting oscillatory flow velocity in water. Third, 'real-time' experiments are conducted in a swimming pool environment by surface mounting two arrays of sensors on the curved hull of a kayak vehicle. The arrays are self-powered and do not need any external power supply, to operate, which greatly benefits in eliminating the need of bulky power supplies on underwater vehicles.

Dark matter bubble chamber detectors use piezoelectric sensors in order to detect and discriminate the acoustic signals emitted by the bubbles grown within the superheated fluid from a nuclear recoil produced by a particle interaction. These sensors are attached to the outside walls of the vessel containing the fluid. The acoustic discrimination depends strongly on the properties of the sensor attached to the outer wall of the vessel that has to meet the requirements of radiopurity and size. With the aim of optimizing the sensor system, a test bench for the characterization of the sensors has been developed. The sensor response for different piezoelectric materials, geometries, matching layers, and backing layers have been measured and contrasted with FEM simulations and analytical models. The results of these studies lead us to have a design criterion for the construction of specific sensors for the next generation of dark matter bubble chamber detectors (250 L)., We acknowledge the financial support of Plan Estatal de Investigacion, ref. FPA2015-65150-C3-2-P (MINECO/FEDER), and Consolider MultiDark CSD2009-00064 (MINECO).

Compressed thin-walled beams with open section are prone to torsional, or flexural-torsional, buckling. Here we present the results of several studies where, by piezoelectric pickups and a universal testing machine, we experimentally detected the natural frequencies and buckling loads of centrally compressed aluminum thin-walled beams with open cruciform section, exhibiting remarkable warping stiffness. We detected the free vibration frequencies for different values of the compressive force and for both free and (at least partially) restrained warping of the end sections. We compared the behavior of integer elements to that of analogous beams, where we introduced a localized damage, i.e., a sharp variation of a cross-section. For the integer elements, we compared the experimental results with those provided by an in-house numerical code, which investigates the elastic stability of possible non-trivial paths of thin-walled beams in a dynamic setting. The results show that, on the one hand, piezoelectric pickups can be efficiently used to extract modal parameters of structural elements; on the other hand, the numerical code proves to be robust and accurate in the determination of the buckling loads of the integer elements, in all the analyzed configurations.

The design and full-wave analysis of piezoelectric micro- needle antenna sensors for minimally invasive near-¯eld detection of cancer-related anomalies of the skin is presented. To this end, an accurate locally conformal ¯nite-di®erence time-domain procedure is adopted. In this way, an insightful understanding of the physical processes detecting the characteristics of the considered class of devices is achieved. This is important to improve the structure reliability, so optimizing the design cycle. In this regard, a suitable sensor layout is described, and discussed in detail. The major benefit of the proposed system stems from the potential for obtaining a superior performance in terms of input impedance matching and efficiency, in combination with an electronically tunable steering property of the near-field radiation intensity which can be profitably used to enhance the illumination and, hence, the localization of possible malignant lesions in the host medium. By using the detailed modeling approach, an extensive parametric study is carried out to analyze the effect produced on the sensor response by variations of the complex permittivity of the skin due to the presence of anomalous cells, and thus useful heuristic discrimination formulas for the evaluation of the exposure level to cancer risk are derived.

In this article, the optimal location and number of piezoelectric sensors is formulated for active vibration control. A modified criterion is used to ensure good observability of the system by considering the minimum number of needed piezoelectric elements. A genetic algorithm is proposed to solve this bi-objective optimization problem. Simulations are presented for a thin plate.

Article first published online: 3 APR 2014 : http://onlinelibrary.wiley.com/doi/10.1002/app.40710/abstract. DOI 10.1002/app.40710., The development of new thermoplastic polymer-based piezoelectric sensors with filament geometry is described. These filaments are appropriate for integration into textiles and provide new possibilities in the design and development of low cost flexible sensors produced at high rates. The developed three-layered piezoelectric monofilaments have been produced by co-extrusion using poly(vinylidene fluoride) and two different polypropylene-based electrically conductive polymers. Filaments with about 800 µm diameter, producing electrical signals proportional to the mechanical deformation applied, were obtained. The signal output has been found adequate for straightforward use with conventional piezoelectric signal conditioning systems. One of the conductive polymers tested allowed better filament geometry and process stability. This paper describes the co-extrusion production process and the results obtained in the electromechanical tests performed., This work was supported by FEDER through the COMPETE Program and by the Portuguese Foundation for Science and Technology (FCT) by project PTDC/CTM/108801/2008 | FCOMP-01-0124-FEDER-009480 and in the framework of the Strategic Project PEst-C/FIS/UI607/20112011, PEst-C/CTM/LA0025/2013 (Strategic Project - LA 25 - 2013-2014) and PEst-C/CTM/UI0264/2011. Authors also thank the project Matepro –Optimizing Materials and Processes”, ref. NORTE-07-0124-FEDER-000037”, co-funded by the “Programa Operacional Regional do Norte” (ON.2 – O Novo Norte), under the “Quadro de Referência Estratégico Nacional” (QREN), through the “Fundo Europeu de Desenvolvimento Regional” (FEDER)

Quartz Tuning Fork (QTF)-based Scanning Probe Microscopy (SPM) is an important field of research. A suitable model for the QTF is important to obtain quantitative measurements with these devices. Analytical models have the limitation of being based on the double cantilever configuration. In this paper, we present an electromechanical finite element model of the QTF electrically excited with two free prongs. The model goes beyond the state-of-the-art of numerical simulations currently found in the literature for this QTF configuration. We present the first numerical analysis of both the electrical and mechanical behavior of QTF devices. Experimental measurements obtained with 10 units of the same model of QTF validate the finite element model with a good agreement.

This work investigates the experimental application of a damage localization technique based on local modal filters on a small clamped-free steel plate equipped with eight piezoelectric (PVDFs) sensors, and excited with a PZT patch. A small damage responsible of a small shift of the eigenfrequencies (less than 4%) is introduced at different locations by fixing a stiffener. By following the guidelines established in previous numerical studies, the modal filters are applied on three local filters in order to locate damage, and a new feature extraction procedure is proposed. Univariate control charts are used to locate automatically all the damage positions correctly. The very nice results obtained with this first experimental application of modal filters based on strains show the real interest of this very simple method for output-only non-model based automated damage localization of real structures. © The Society for Experimental Mechanics, Inc. 2013., SCOPUS: cp.p, info:eu-repo/semantics/published

The surface morphology of gold electrodes on piezoelectric quartz crystals was characterized by scanning electron microscopy and scanning tunnelling microscopy. Sensors with various coating materials as polymers, liquid crystal and nitrocompounds have been employed to demonstrate the importance of surface properties in determining the response of the device. The sensors were evaluated for detection of organophosphorus and nitroaromatic vapours in air.

This paper considers the optimal placement of collocated piezoelectric actuator-sensor pairs on flexible beams using a model-based linear quadratic regulator (LQR) controller. A finite element method based on Euler-Bernoulli beam theory is used. The contributions of piezoelectric sensor and actuator patches to the mass and stiffness of the beam are considered. The LQR performance is taken as the objective for finding the optimal location of sensor-actuator pairs. The problem is formulated as a multi-input multi-output (MIMO) model control. The discrete optimal sensor and actuator location problem is formulated in the framework of a zero-one optimization problem which is solved using genetic algorithms (GAs). Classical control strategies like direct proportional feedback, constant gain negative velocity feedback and the LQR optimal control scheme are applied to study the control effectiveness. The study of the optimal location of actuators and sensors is carried out for different boundary conditions of beams like cantilever, simply supported and clamped boundary conditions. � 2008 IOP Publishing Ltd.

Tactile sensing transfers complex interactive information in a most intuitive sense. Such a populated set of data from the environment and human interactions necessitates various degrees of information from both modular and distributed areas. A sensor design that could provide such types of feedback becomes challenging when the target component has a nonuniform, agile, high resolution, and soft surface. This paper presents an innovative methodology for the manufacture of novel soft sensors that have a high resolution sensing array due to the sensitivity of ceramic piezoelectric (PZT) elements, while uncommonly matched with the high stretchability of the soft substrate and electrode design. Further, they have a low profile and their transfer function is easy to tune by changing the material and thickness of the soft substrate in which the PZTs are embedded. In this manuscript, we present experimental results of the soft sensor prototypes: PZTs arranged in a four by two array form, measuring 1.5–2.3 mm in thickness, with the sensitivity in the range of 0.07–0.12 of the normalized signal change per unit force. We have conducted extensive tests under dynamic loading conditions that include impact, step and cyclic. The presented prototype's mechanical and functional capacities are promising for applications in biomedical systems where soft, wearable and high precision sensors are needed.

Active damping in a FRP composite cylindrical shell with collocated piezoelectric sensors/actuators is studied. The electrode on the sensors/actuators are spatially shaped to reduce spillover between circumferential modes. A three noded, isoparametric, semi-analytical finite element is developed and used to model the cylindrical shell. The element is based on a mixed piezoelectric shell theory which makes a single layer assumption for the displacements and a layerwise assumption for the electric potential. The effects of location of patch of collocated piezoelectric sensors/actuators, percentage length of the shell covered with these patches, fiber angle of the laminae in the composite laminate, stacking sequence of laminae in a laminate and skew angle of the sensor/actuator piezoelectric material, on the system damping for various modes is studied. (C) 2000 Elsevier Science Ltd. All rights reserved.Active damping in a FRP composite cylindrical shell with collocated piezoelectric sensors/actuators is studied. The electrode on the sensors/actuators are spatially shaped to reduce spillover between circumferential modes. A three noded, isoparametric, semi-analytical finite element is developed and used to model the cylindrical shell. The element is based on a mixed piezoelectric shell theory which makes a single layer assumption for the displacements and a layerwise assumption for the electric potential. The effects of location of patch of collocated piezoelectric sensors/actuators, percentage length of the shell covered with these patches, fiber angle of the laminae in the composite laminate, stacking sequence of laminae in a laminate and skew angle of the sensor/actuator piezoelectric material, on the system damping for various modes is studied.

A coated quartz crystal microbalance is used for the determination of carbon dioxide. Coating of crystals with tetramethylammonium fluoride tetrahydrate is reported for the first time, and its behaviour, in terms of CO2 interaction at different temperatures, is discussed. This new coating gives greater stability to the calibration curve than N,N,N′ ,N′-tetrakis(2-hydroxyethyl)ethylenediamine but less sensitivity for carbon dioxide, especially at higher CO2 concentrations.