Roughness quartz crystal microbalance

Keywords Quartz crystal microbalance Roughness Slippage Thin films... 

An electrochemical quartz crystal microbalance (EQCM or QCM) can be used to estimate the surface roughness of deposited lithium [43],... 

To mimic the PG electrode surface for QCM measurements of layers adsorbed on the gold-quartz resonators, we first chemisorb a mixed monolayer of mercaptopropionic acid/mercaptopropanol. This layer is represented by the first point in Fig. 2, labeled MPA. The second layer is PDDA. Quartz crystal microbalance frequency decreasing in a roughly linear fashion and at regular intervals for the multiple adsorption steps demonstrates repeatable adsorption for the two DNA/en-zyme films. Relative precision of layer formation on multiple resonators within 15% can be achieved. Film thicknesses and component weights in Table 1 were obtained by analyzing the QCM data with Eqs. 1 and 2. 

Daikhin, L. Urbakh, M., Influence of surface roughness on the quartz crystal microbalance response in a solution new configuration for qcm studies, Faraday Discuss. 1997,107, 27-38. 

Abstract In this chapter we discuss the results of theoretical and experimental studies of the structure and dynamics at solid-liquid interfaces employing the quartz crystal microbalance (QCM). Various models for the mechanical contact between the oscillating quartz crystal and the liquid are described, and theoretical predictions are compared with the experimental results. Special attention is paid to consideration of the influence of slippage and surface roughness on the QCM response at the solid-liquid interface. The main question, which we would like to answer in this chapter, is what information on... 

Fundamental frequency of the resonator Correlation function for surface roughness Root mean square height of a roughness Wave vector of shear waves in quartz, (Uy pq//rq Correlation length of surface roughness Thickness of the liquid film Thickness of interfacial layer Molecular dynamics Pressure in a liquid Quartz crystal microbalance Hydrodynamic roughness factor Electrochemical roughness factor Coordinates (normal and lateral)... 

In 2003, Tsionsky, Daikhin, Urbakh, and Gileadi [21] published a very thorough treatment of the metal/solution interface as examined by the electrochemical quartz crystal microbalance, with emphasis on the misinterpretations of data that can occur if the basic physics and chemistry at the interface are not understood. Topics covered include the electrical double-layer/electrostatic adsorption, the adsorption of organic and inorganic species, metal deposition, and the influence of roughness on the response of the QCM in liquids. 

Figure 4.17 Shift and change of the resonance frequency of a quartz crystal microbalance, real part of the admittance versus frequency, /q, Wq, resonance frequency and full width at half maximum (FWHM) of the initial gold electrode,/j, w, resonance frequency and FWHM of a gold electrode after formation of a rigid and smooth surface film (no damping), resonance frequency and FWHM of a gold electrode after formation of a viscoelestic and/or rough surface film (strong damping).

Urbakh M, Daikhin L (1997) Influence of siuface roughness rai the quartz crystal microbalance response in a sohitioiL A new configuration for QCM studies. Earaday Discuss 107 27—38... 

Many techniques have been developed to characterize the properties of the SEI layer on the anodes, such as X-ray photoelectron spectroscopy (XPS), EELS and selected area electron diffraction (SAED) " as well as FTIR and HRTEM. Most of these techniques provide ex situ information on both the elechonic and crystalline stmctural variations of the electrode. Electrochemical impedance spectroscopy (EIS) and electrochemical quartz crystal microbalance (ECQCM) can provide in situ information of macro-scale properties of the SEI layers. Reflectance FTIR techniques and atomic force microscopy (AFM) have been used in situ to study the surface of metal lithium and electrochemically nonactive electrodes, such as Pt, Au and Ni as well. Nevertheless, it is still difficult to study rough electrode surfaces of composite materials in lithium ion batteries with these techniques. In addition, none of the above techniques, except for FTIR spectroscopy, can provide structural information at the molecular levels. 

Acoustic and optical gas sensors, respectively, were developed by coating CNTs onto the chips of a quartz crystal microbalances (QCM) and silica optical fibers (SOFs). As shown in Figure 7.7c, CNT-coated QCM crystals were roughly 1-2 orders of magnitude more sensitive than uncoated QCM crystals. Also, it was danonstrated that CNT-coated SOFs had similar low limits of detection and enhanced sensitivity. 

S. Wehner, K. Wondraczek, D. Johannsmann, and A. Bund, Roughness-induced acoustic second-harmonic generation during electrochemical metal deposition on the quartz-crystal microbalance, Langmuir, 20, 2356-2360 (2004). 

The quartz crystal resonator is a useful device for the study of thin-layer and interfacial phenomena. The crystals commonly employed have a fundamental resonance frequency of 5 -10 MHz and a resolution of the order of 0.1 -0.5 Hz. This high resolution makes the device sensitive to a myriad of physical phenomena, some of which are interrelated and some quite independent of each other. It cannot be overemphasized that the quartz crystal resonator acts as a true microbalance (more appropriately a nanobalance) only if in the course of the process being studied, the nature of the interface (its roughness, sHp-page, the density and viscosity of the solution adjacent to it, and the structure of the solvent in contact with it) is maintained constant. 

In order for both mass and heat-flow sensors to operate, the thin-film sample must adhere to the top surface of the QCM and be of uniform thickness. The mechanical behaviour of films on the quartz microbalance has been modeled by Kanazawa(12), who examined the amplitude of the shear displacement in the quartz crystal and in the overlying film for several cases. For a 1 volt peak RF applied voltage typical of the Stanford Research Systems oscillator driver, the amplitude of the shear wave of a bare crystal is 132 nm. Mecca [29] has calculated the inertial acceleration at the centre of a similar quartz resonator, and finds that it is roughly 10 g, where g is the gravitational constant. At these extremely high accelerations, powder or polycrystalline samples do not follow the transverse motion of the QCM surface and cannot be used without being physically bound to the surface with a thin adhesive layer. 

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