Poly(vinyl acetate) (PVAc) was coated onto one side of a silicon cantilever, and the variations with temperature in the deflection, resonance frequency, and Q factor of the PVAc-coated silicon cantilever were measured simultaneously. The changes in the resonance frequency and the inverse of the Q factor of the cantilever are related to the variations in the elastic modulus and the loss tangent of PVAc, respectively. The loss modulus of PVAc was calculated from the resonance frequency and Q factor and used to determine the glass transition temperature (T g) of PVAc (66 °C), which was found to be higher than that obtained from the cantilever deflection (43 °C); this difference is attributed to the high resonance frequency of the cantilever (or the fast rate of the applied stress). A series of measurements at various frequencies were carried out to obtain the accurate T g and apparent activation energy for the glass transition.

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The kinetics of CO(2) adsorption and desorption over amine-functionalized mesoporous silica were investigated using silicon microcantilever arrays. Three types of mesoporous silica with different pore sizes were synthesized and functionalized with a variety of amine molecules. After depositing the silica sorbents onto the free end of each cantilever in an array, mass changes due to the adsorption and desorption of CO(2) were determined in situ with picogram sensitivity by measuring variations in the cantilever frequencies. The adsorption and desorption kinetics were found to be diffusion-controlled, and the kinetics were accelerated by increasing the temperature and pore size. The activation energies for adsorption and desorption of CO(2) were determined from Arrhenius plots.

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