A New Quartz Crystal Microbalance Measuring Method with Expansive Frequency Range and Broadband Adaptive Response Capacity

Quartz crystal microbalance (QCM) measuring instruments are suffering from the extremely high requirements for crystal cutting techniques and the incompleteness of measuring parameters. To solve these problems, we proposed a modified measuring method based on quadrature demodulation. This method showed broadband adaptive response, high frequency resolution, and capacity of continuously obtaining both resonance frequencies and dissipation factor (D). The results indicated that at room temperature, the frequency measuring adaptive response was 1–9 MHz while the frequency resolution was < 1 Hz. Moreover, along with the homogeneous superimposition of poly acrylic acid (PAA) films at the working electrode, the crystal frequency drifts changed linearly within the measured range. Along with the volatilization of different solvents, the values of measured D were effective and continuous along the time axis. To sum up, this new method is superior over the traditional ones in terms of low material costs and high parameter richness.

Graphical AbstractThe modified QCM measurement system was built by 9 discrete modules. It could automatically match the cut-formed quartz crystals within frequency of 1–9 MHz and precisely measure both the crystal resonance frequencies and dissipation factor D, which met the requirements for low-costing and high-sensitivity QCM analysis.Figure optionsDownload full-size imageDownload as PowerPoint slide