Fast three-step method for shear moduli calculation from quartz crystal resonator measurements

Quartz crystal resonator measurements can be used for polymer material char acterization. The non-gravimetric regime of these resonators is exploited: the electrical response of polymer-coated quartz resonators depends on the polymer shear modulus. Previously reported methods employ an electrical adm ittance analysis together with difficult and time-consuming data fitting pr ocedures to calculate the film shear modulus, This contribution presents a fast and accurate three-step method for the calculation of complex shear mo duli of polymer films from quartz crystal resonator measurements. In the fi rst step, the acoustic load impedance is calculated from the electrical adm ittance of the quartz crystal. The key point of this method is the applicat ion of a family of approximations for the calculation of the shear modulus from the acoustic load impedance in the second step. In the third step, the best approximation is improved further in an iterative procedure.