Determination of the Viscoelastic Properties of Polymer Films Using a Compensated Phase-Locked Oscillator Circuit

Abstract

Using a combination of the quartz crystal microbalance and a corresponding physical model for the compound resonator, the viscoelastic properties of polymer films have been studied. By using a compensated phase-locked oscillator system, both resonant frequency and resistance (motional resistance of the Butterworth-Van Dyke equivalent circuit) can be measured simultaneously. The behavior of resistance as a function of film thickness or corresponding frequency shift provides a means not only for quantitatively determining the shear viscosity and elastic modulus of films but also for qualitatively comparing various systems. The physical model is extended to include four layers for describing dissolving/swelling films that form an energy-dissipative, interfacial layer. If the underlying film is rigid and acoustically thin, then the four-layer case can be reduced to a simplified three-layer description.

FGF‐2 signaling is sufficient to induce dermal condensations during feather development

“…The electrical characteristics of an uncoated quartz QCM are well represented as a simple RLC damped resonator equivalent circuit with a complex impedance Z q . With an impedance analyzer, it is possible to measure both the real and imaginary parts of Z q for TSM resonators 27–34. The width of the resonance for an uncoated resonator is only 10–20 Hz, and the mechanical damping within the quartz that gives rise to this broadening can be determined by measuring the motional resistance , R , of the resonator ( vide infra ), typically ∼10 ohms.…”

“…When thin, stiff films are deposited on the QCM surface the increase in R is small, but softer, thicker films (i.e., rubbery polymers 5–10 μm thick) can strongly increase R . Lee et al29 have measured the viscoelastic properties of polymer films with a phase locked oscillator circuit.…”

Viscoelastic potential-induced changes in acoustically thin films explored by quartz crystal microbalance with motional resistance monitoring

“…Thus, can be expressed as a sum of contributions from each layer and interface which the acoustic wave crosses [29,[42][43][44][45]:…”

Dissolution behavior of resist polymers studied using quartz crystal microbalance method

“…If the model exhibits swelling, the interfacial transition layer exhibits a greatly reduced elastic modulus and lowered viscosity compared with the solid polymer before swelling. The model was mechanically treated using non-linear simultaneous equations, and it elucidated the swelling behavior of a norbornene polymer 8 . Taxonomy of the dissolution processes has been proposed for representative resist copolymers, measured using QCM frequency-resistance analysis and optical reflectance 9 .…”