| Quartz crystal resonator (QCR). which is a sensitive and practical tool for measurement of the changes of interface, has been increasingly applied in the studies of a wide variety of phenomena including film growth, interfacial modification, and chemical reaction at interfaces. Therefore, it has got certain applications in physical, chemical, biological and medicine. This dissertation will develop a general model that describes the equivalent circuit model and resonator response of QCR. A QCR sensor real-time data acquisition system based on impedance analysis is designed. The electrical responses of QCR for the viscoelastic films of finite thickness were discussed by the resonant frequency shift Δf and half-band half width shift AF, and it is applied to investigate the glass transition of the Poly(vinyl butyral) (PVB) thin films. Major research achievements and contributions of this dissertation are summarized as follows: 1. The electrical model of the non-piezoelectric and piezoelectric slab was deduced base on one dimensional acoustic model. Then the complex frequency shifts Δf+iΔΓresponse of a quartz resonator with acoustic loads was proposed. This model incorporates a physically divers set of single-component loadings, which will be very useful for a better understanding of the resonance behavior of the quartz resonator. Error analysis of the equation of response of QCR for a single viscoelastic film and error sources in the procedure to determine the complex frequency shift was discussed through simulation.2. The QCR sensor acquisition system with high-rate acquisition, manual manipulation convenience and high accuracy is designed. Based on network analyzer, this acquisition system proposes an effective fitting method to compute the signal-to-noise ratio of a QCR and also with intelligent real-time modifying network analyzer, the consistence of the signal figure of acquisition and theoretical analysis is achieved. This system has the advantage of high measurement accuracy, good stability and the capability to perform real-time monitoring and analysis on the dynamic processes. The different behaviors of the characteristic frequencies upon perturbation of the equivalent circuit parameters are studied by numerical simulation and the overtones, n, the motional resistance, Rm, and static capacitance, Co, effect on the frequencies was discussed, which provides important reference for the choose of resonant frequency in actual measurement.3. We show a method that allows for determination of viscoelastic moduli of films deposited on the surface of a quartz crystal by measuring the frequency shifts and the broadening of the acoustic resonance of the crystal as a resonator. The method is based on transcendental equations which describes mechanical response of the quartz resonator with the deposited films. It differs from the currently widely used ones which use a thin film approximation by solving the transcendental equations numerically, in determining viscoelasticity of the films. The method is not constraint to the range of the elastic moduli of the film, except where the acoustic film resonance occurs, and thus can be applied to the study of a wide variety of materials under different conditions. The approach has been tested on poly(vinyl butyral) thin films to show that such an approach can be used for studying glass transition in polymer films deposited on a quartz crystal surface.4. We demonstrate that a QCR is applicable to investigate the glass transition of the PVB thin films by the simultaneous measurement of both resonant frequency and bandwidths on several overtones. The response of resonant frequency and bandwidths of film coated quartz crystal directly reflects the information about surface mass and film shear modulus. These results indicate the feasibility of using QCR technique to characterize glass transition temperature and viscoelastic properties of the PVB thin films.
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