Gelation monitoring by quartz microbalance in pulse mode

Classical viscoelastic measurement setup with a quartz crystal microbalance uses a steady state input signal in order to measure the complex equivalent electrical parameters. Using a network analyzer, this method enables the measurement of the equivalent impedance around the first resonance peak of the quartz within a tiny frequency range (typically 10 kHz around a 6 MHz resonance frequency). However, due to the network analyzer acquisition time, such a setup cannot make two successive acquisitions in less than 15 s for one resonance peak. We excite the quartz by a short pulse and record its time impulse response. This kind of excitation allows us to record higher resonance peaks (up to the 11th order) and to reduce drastically the acquisition time, enabling up to 100 acquisitions per second.