Surface acoustic wave , vapor

Grate, J. W. Patrash, S. J. Kaganove, S. N. Wise, B. M., Hydrogen bond acidic polymers for surface acoustic wave vapor sensors and arrays, Anal. Chem. 1999, 71, 1033-1040. 

J.W Grate, A. Snow, D.S. BaUantine, H. Wohltjen, M.H. Abraham, R.A. McGill, P. Sasson, Determination of partition coefficients from surface acoustic wave vapor sensor responses and correlation with gas-liquid chromatographic paitition coefficients. Anal. Chem. 60, 869-875 (1988)... 

Acoustic wave sensors are also used to detect nerve and blister agents. The surface acoustic wave chemical agent detector (SAW Mini-CAD) is a commercially available, pocket-sized instrument that can monitor for trace levels of toxic vapors of sulfur-based mustard agents (e.g., distilled mustard) and G nerve agents (e.g., tabun, sarin, soman) with a high degree of specificity. Colorimetric tubes are the... 

Amidoxime-Functionalized Coatings for Surface Acoustic Wave Detection of Simulant Vapors... 

There are several applications of ZnO that are due to its excellent piezoelectric properties [28,164]. Examples are surface-acoustic wave (SAW) devices and piezoelectric sensors [28,165-167]. Typically, SAW devices are used as band pass filters in the tele-communications industry, primarily in mobile phones and base stations. Emerging field for SAW devices are sensors in automotive applications (torque and pressure sensors), medical applications (chemical sensors), and other industrial applications (vapor, humidity, temperature, and mass sensors). Advantages of acoustic wave sensors are low costs, ruggedness, and a high sensitivity. Some sensors can even be interrogated wirelessly, i.e., such sensors do not require a power source. 

Grate, J.W., Abraham, M.H., Du, C.M., et al. (1995). Examination of vapor sorption by fiillerene, fullerene-coated surface acoustic wave sensonrs, graphite, and low-polarity polymers using hnear solvation energy relationships. Langmuir, 11, 2125-30. 

A new Pt(II) polyyne polymer, P15, prepared from the reaction of cfs-[Pt(PPh3)2Cl2] with l,4-diethynyl-2,5-dihexadecyloxybenzene using the extended one pot polymerization route, was tested for its sensing properties and showed fast and reproducible response to relative humidity variations and methanol vapor in surface acoustic-wave (SAW) sensors.46 A SAW sensor was fabricated from polymer P15 as a sensitive membrane, and the polymer was deposited as thin film on the surface of SAW delay lines implemented on three different piezoelectric substrates. High sensitivity and reproducibility were recorded for such devices. The acoustic characterization of the polymer film was also studied with the aid of theoretical results obtained by the perturbation theory. 

Grate J W, Rose-Pehrsson S L, Venezky D L, Klusty M and Wohltjen H 1993 Smart sensor system for trace organophosphorus and organosulfur vapor detection employing a temperature-controlled array of surface acoustic wave sensors, automated sample preconcentration and pattern recognition Anal. Chem. 65 1868... 

Chemical sensors have been reported that are based on quartz micro balances or surface acoustic wave oscillators coated with the trimethylsilyl ethers of and 6 " and that are claimed to detect various solvent vapors in ppm amounts. ... 

Wohltjen H., Mechanism of operation and design considerations for surface acoustic wave device vapor sensors, Sens, and Actuators B, 5, 307-325, 1984. 

Surface acoustic wave (SAW) vapor/thin film sensor... 

Fig. 3.9 (Left) Surface acoustic wave (SAW) resonator and (right) SAW dual delay line device (on penny). Quartz-based SAW sensors, coated with chemically selective films, can detect chemical vapors. Sensor arrays, with diverse coatings, can detect multiple chemical vapors, image courtesy of pacific northwest national laboratory...

Vapor Detection with Surface Acoustic Wave Microsensors... 

This paper has dealt exclusively with SAW sensors that exploit the mass sensitivity of the device to achieve chemical vapor detection. Schemes to exploit the SAW sensitivity to coating conductance changes (17) or elastic modulus changes should afford new opportunities for imaginative chemical vapor sensor designs. Finally, the field of liquid phase chemical analysis may also yield to surface acoustic wave devices that utilize plate waves and horizontally polarized shear waves to minimize acoustic losses in the liquid (18). 

Selective Measurement of Vinyl Acetate Vapor Using a Coated Surface Acoustic Wave Oscillator... 

A coated surface-acoustic-wave (SAW) sensor capable of real-time, selective measurement of vinyl acetate vapor in the presence of several olefin and non-olefin cocontaminants is described. The coating film en loyed consists of the solid platinum-ethylene Ji-complex, trans-PtCl (ethylene)(pyridine). occluded in a polyisobutylene matrix. Exposure to vinyl acetate results in displacement of ethylene from the cott lex and formation of the vinyl acetate-substituted complex. Subsequent regeneration of the original reagent is possible by treatment with ethylene gas, in situ. A lower detection limit of 5 ppm of vinyl acetate is achieved for operation at 46 C. The industrial-hygiene applications of the sensor are discussed. 

Chemical sensors based on acoustic wave (AW) devices have been studied for a number of sensing applications, the majority of which fall in the category of gas and vapor detection (1-8). Recently, the use of these sensors in liquid environments has been explored (9-13). AW sensors utilize various types of acoustic waves, including the surface acoustic wave (SAW), the shear-horizontal acoustic plate mode (SH-APM) (10-13), and the Lamb wave (also a plate mode) (3.14). Even though most studies of these piezoelectric sensors have centered on SAW devices (1.2.4-8), differences in the propagation characteristics of the various acoustic modes make some better suited than others for a given sensing application. 

In the area of chemical sensors, thin polymer films are routinely used as coatings for the semi-selective sorption of chemical vapors. One sensor technology, the surface acoustic wave (SAW) device, has demonstrated excellent sensitivity as a vapor sensor when coated with films having appropriate solubility properties (2). To date, most sensor applications have utilized the extreme mass sensitivity of the devices. In this paper, we will examine the response mechanisms of the SAW sensor and demonstrate its sensitivity to changes in the elastic properties of the coating materials. Finally, we will discuss the significance of these results in terms of current sensor applications, and the advantages of the SAW for polymeric materials characterization. 

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