Influence of the Surface Microstructure on the Coupling Between a Quartz Oscillator and a Liquid

Beck, Ralf; Pittermann, Udo; Weil, K. G.

doi:10.1149/1.2069239

“…It has long been known that a crystal with a rough surface has an excess liquid phase response, primarily in its frequency decrease, compared to that predicted by the Kanazawa-Gordon equation. [1][2][3][4][5][6][7][8][9][10][11][12][13] One suggested method of accounting for this response has been to view the response as composed of a Kanazawa term 14 accounting for the entrainment of the liquid plus a Sauerbrey 15 rigid-mass-type term with the mass being given by the liquid ''trapped'' within the surface structure of the crystal. 1,8,13 The assumed additivity of these terms has been the starting point of the model and has not been directly derived from any wave equation for the system.…”

Section: Introductionmentioning

confidence: 99%

Surface roughness and interfacial slip boundary condition for quartz crystal microbalances

McHale

¹

,

Newton

²

2004

Journal of Applied Physics

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The response of a quartz crystal microbalance ͑QCM͒ is considered using a wave equation for the substrate and the Navier-Stokes equations for a finite liquid layer under a slip boundary condition. It is shown that when the slip length to shear wave penetration depth is small, the first-order effect of slip is only present in the frequency response. Importantly, in this approximation the frequency response satisfies an additivity relation with a net response equal to a Kanazawa liquid term plus an additional Sauerbrey ''rigid'' liquid mass. For the slip length to result in an enhanced frequency decrease compared to a no-slip boundary condition, it is shown that the slip length must be negative so that the slip plane is located on the liquid side of the interface. It is argued that the physical application of such a negative slip length could be to the liquid phase response of a QCM with a completely wetted rough surface. Effectively, the model recovers the starting assumption of additivity used in the trapped mass model for the liquid phase response of a QCM having a rough surface. When applying the slip boundary condition to the rough surface problem, slip is not at a molecular level, but is a formal hydrodynamic boundary condition which relates the response of the QCM to that expected from a QCM with a smooth surface. Finally, possible interpretations of the results in terms of acoustic reflectivity are developed and the potential limitations of the additivity result should vapor trapping occur are discussed.

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“…The effect of surface roughness of the crystal during measurements in liquids is widely discussed in literature [20,[26][27][28]. Depending on the surface roughness of the quartz electrodes and the film thickness of the sample, there is more or less rigidly bound liquid [16,29]. For very thin films with thicknesses below the mean surface roughness, the energy dissipation is strongly reduced and the sample layer can be analyzed by the Sauerbrey equation.…”

Section: Preliminary Considerationsmentioning

confidence: 99%

“…For a flat plate, the Sauerbrey equation loses its validity approximately at 35 mol % water (damping ratio of about 2 %). If the above-mentioned roughness, in our case the arithmetic average of roughness is 100 nm, is taken into account, thin films with a thickness below the average roughness of the surface behave like solids [29] and almost no damping occurs. The Sauerbrey equation can be applied to water contents up to 95 mol %.…”

Section: Validation Of the Sauerbrey Equation Duringmentioning

confidence: 99%

Improved Methodology for Absorption Measurements in Ionic Liquids with a Quartz Crystal Microbalance

Schmidt

¹

,

Heym

²

2017

Chem Eng & Technol

2

0

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The knowledge of vapor‐liquid equilibrium data of mixtures with performance chemicals, such as ionic liquids (ILs), is highly important for technical applications. New insights into the utilization of quartz crystal microbalances (QCMs) for reliable absorption measurements in ILs are provided. The validity of the Sauerbrey equation for rigid films and bulk liquids is widely discussed in literature. This work shows how to ensure the validity of the Sauerbrey equation during absorption measurements in thin liquid films. Furthermore, the advantages of the employment of rough electrodes for absorption measurements within thin liquid films in comparison to polished ones are described in detail. Important recommendations in application of the QCM systems regarding gravimetric measurements are presented.

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“…A resistive component R 0 The resistance R 0 is a measure of mechanical losses from the vibrating quartz, and it therefore reflects the viscoelastic properties of the contact- ing liquid [240], [241] or a deposited film [242]. Surface roughness also influences the value of R 0 [243]. This is often not considered in certain applications.…”

Section: Fundamental Principles and Basic Types Of Transducersmentioning

confidence: 99%

Chemical and Biochemical Sensors

Cammann¹,

Roß²,

Katerkamp³

et al. 2001

Ullmann's Encyclopedia of Industrial Chemistry

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The article contains sections titled: 1. Introduction to the Field of Sensors and Actuators 2. Chemical Sensors 2.1. Introduction 2.2. Molecular Recognition Processes and Corresponding Selectivities 2.2.1. Catalytic Processes in Calorimetric Devices 2.2.2. Reactions at Semiconductor Surfaces and Interfaces Influencing Surface or Bulk Conductivities 2.2.3. Selective Ion Conductivities in Solid‐State Materials 2.2.4. Selective Adsorption ‐ Distribution and Supramolecular Chemistry at Interfaces 2.2.5. Selective Charge‐Transfer Processes at Ion‐Selective Electrodes (Potentiometry) 2.2.6. Selective Electrochemical Reactions at Working Electrodes (Voltammetry and Amperometry) 2.2.7. Molecular Recognition Processes Based on Molecular Biological Principles 2.3. Transducers for Molecular Recognition: Processes and Sensitivities 2.3.1. Electrochemical Sensors 2.3.1.1. Self‐Indicating Potentiometric Electrodes 2.3.1.2. Voltammetric and Amperometric Cells 2.3.1.3. Conductance Devices 2.3.1.4. Ion‐Selective Field‐Effect Transistors (ISFETs) 2.3.2. Optical Sensors 2.3.2.1. Fiber‐Optical Sensors 2.3.2.2. Integrated Optical Chemical and Biochemical Sensors 2.3.2.3. Surface Plasmon Resonance 2.3.2.4. Reflectometric Interference Spectroscopy 2.3.3. Mass‐Sensitive Devices 2.3.3.1. Introduction 2.3.3.2. Fundamental Principles and Basic Types of Transducers 2.3.3.3. Theoretical Background 2.3.3.4. Technical Considerations 2.3.3.5. Specific Applications 2.3.3.6. Conclusions and Outlook 2.3.4. Calorimetric Devices 2.4. Problems Associated with Chemical Sensors 2.5. Multisensor Arrays, Electronic Noses, and Tongues 3. Biochemical Sensors (Biosensors) 3.1. Definitions, General Construction, and Classification 3.2. Biocatalytic (Metabolic) Sensors 3.2.1. Monoenzyme Sensors 3.2.2. Multienzyme Sensors 3.2.3. Enzyme Sensors for Inhibitors ‐ Toxic Effect Sensors 3.2.4. Biosensors Utilizing Intact Biological Receptors 3.3. Affinity Sensors ‐ Immuno‐Probes 3.3.1. Direct‐Sensing Immuno‐Probes without Marker Molecules 3.3.2. Indirect‐Sensing Immuno‐Probes using Marker Molecules 3.4. Whole‐Cell Biosensors 3.5. Problems and Future Prospects 4. Actuators and Instrumentation 5. Future Trends and Outlook

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Influence of the Surface Microstructure on the Coupling Between a Quartz Oscillator and a Liquid

Cited by 99 publications

References 2 publications

Surface roughness and interfacial slip boundary condition for quartz crystal microbalances

Surface roughness and interfacial slip boundary condition for quartz crystal microbalances

Improved Methodology for Absorption Measurements in Ionic Liquids with a Quartz Crystal Microbalance

Chemical and Biochemical Sensors

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