A method for characterizing mechanical properties of sugar films using a piezoelectric-excited millimeter sized cantilever (PEMC) sensor

Resonant-mode cantilevers have been investigated widely for detection of target analyte mass. We examine its application for measuring mechanical property of an organic film. A cantilever resonant frequency depends both on its mass and its spring constant. A change in either one of them causes resonant frequency shifts. Piezoelectric excited millimeter sized cantilever (PEMC) sensors exhibit high mass-change sensitivity (2 fg/Hz) at high-order resonant modes present in the frequency range of 800–1000 kHz. The response of this high-order mode to the formation of a sugar film membrane provides experimental data for characterizing the mechanical properties of the sugar film. Sugar film formation, surprisingly, caused a significant resonant frequency increase of greater than 20 kHz. The high-order mode was highly sensitive to spring constant changes caused by the sugar film and was characterized by varying thickness and temperature of the sugar films.