Die Schwingquarzmethode

Abstract

In the last decade, the Quarz Crystal Micro Balance has proved its enormous capability to be suitable to a wide range of applications in thc fields of chemistry, physics, materials and surface science, maritime and medical research as well as in sensor technology. The physical basis of these features are mega Hertz shear oscillations which create oscillatory movements at the solid/liquid junction. They give rise to an acceleration which sur‐ passes the acceleration of gravity by several orders of niagnitude. These unique movement conditions allow, besides the well known mass sensitivity of several nanograms, nanotribologic investigations between metallic substrata and monolayer deposits of foreign materials. It senses grain size effects in metallic deposits and allows the complete determination of the complex and anisotropic shear compliance of thin polymer layers. With a structured oscillator surface density and viscosity of a liquid phase can be determined independently. It also allows monitoring of chemical reactions with a time resolution < lms.

Characterization of the Viscoelasticity and the Surface Roughness of Electrochemically Prepared Conducting Polymer Films by Impedance Measurements at Quartz Crystals

“…4b, solid up triangles͒, this situation corresponds closest to the pure trapped liquid case discussed by Schumacher. 15 Because of the high density of the solvent the measured ⌬ f strongly deviates from the calculated value ͑Fig. 4a͒.…”

“…13 In the case of a polymer-coated quartz in a liquid there are several mechanical effects, which will act as mechanical impedances, the viscoelastic load of the polymer layer, the viscous interaction of the rough polymer surface with the liquid phase, coupling of shear and compressional modes, 14 and others. 15 Many QCM investigations at conducting polymers are performed with oscillator-based equipment, which gives no information about the damping properties of the polymer layer. The thus measured frequency shift is a complicated sum signal of the contributions mentioned above.…”

Combined QCM-D/GE as a tool to characterize stimuli-responsive swelling of and protein adsorption on polymer brushes grafted onto 3D-nanostructures

“…The measuring principle of the QCM is based on the inverse piezoelectric effect, where the application of alternating voltage to a piezoelectric crystal leads to an oscillatory motion [33][34][35][36]. The resonance frequency of the quartz sensor is sensitive to changes induced by the contact with the ambient and processes occurring on its surface, for instance, adsorption processes, which can be observed in situ with high temporal resolution.…”

On the electrodeposition of tantalum from three different ionic liquids with the bis(trifluoromethyl sulfonyl) amide anion

“…Details about the EQCM technique can be found in ref. [16][17][18][19]. In short, we use a special EQCM, which allows us to obtain simultaneously information about the dissipated energy of the quartz crystal and its resonance frequency.…”