Kinetics of viscoelasticity in the electric double layer following steps in the electrode potential studied by a fast electrochemical quartz crystal microbalance (EQCM).

Changes in the viscoelasticity of the electric double layer following steps in electrode potential were studied with an electrochemical quartz crystal microbalance (EQCM). The overtone scaling was the same as in gravimetry (-Δf/n≈ const with Δf the frequency shift and n the overtone order). Changes in half-bandwidth were smaller than changes in frequency.

Compressional-Wave Effects in the Operation of a Quartz Crystal Microbalance in Liquids:Dependence on Overtone Order.

The operation of the quartz crystal microbalance (QCM) in liquids is plagued by small flexural admixtures to the thickness-shear deformation. The resonator surface moves not only in the transverse direction, but also along the surface normal, thereby emitting compressional waves into the liquid. Using a simple analytical model and laser Doppler vibrometry, we show that the flexural admixtures are stronger on the fundamental mode than on the overtones.

Characterizing protein-protein-interaction in high-concentration monoclonal antibody systems with the quartz crystal microbalance.

Making use of a quartz crystal microbalance (QCM), concentrated solutions of therapeutic antibodies were studied with respect to their behavior under shear excitation with frequencies in the MHz range. At high protein concentration and neutral pH, viscoelastic behavior was found in the sense that the storage modulus, G', was nonzero. Fits of the frequency dependence of G'(ω) and G''(ω) (G'' being the loss modulus) using the Maxwell-model produced good agreement with the experimental data.

Probing the electrical impedance of thin films on a quartz crystal microbalance (QCM), making use of frequency shifts and piezoelectric stiffening.

Using a temperature-responsive polymer film as an example, it was shown that a conventional quartz crystal microbalance (QCM) can probe a sample's electrical properties in addition to its thickness and softness. The film's electrical impedance was accessed by alternating between the driving voltage being applied to the front electrode and the back electrode. The opposing electrode was grounded in both cases.

Lipid phase behavior studied with a quartz crystal microbalance: A technique for biophysical studies with applications in screening.

Quartz crystal microbalance (QCM) is emerging as a versatile tool for studying lipid phase behavior. The technique is attractive for fundamental biophysical studies as well applications because of its simplicity, flexibility, and ability to work with very small amounts of material crucial for biomedical studies. Further progress hinges on the understanding of the mechanism, by which a surface-acoustic technique such as QCM, senses lipid phase changes.

Coupled resonances allow studying the aging of adhesive contacts between a QCM surface and single, micrometer-sized particles.

Interparticle contacts and contacts between particles and surfaces are known to change over time. The contact area, the contact stiffness, and the contact strength usually increase as the contact ages. Contact aging is mostly driven by capillary forces, but also by plastic deformation.