Influence of Gas Velocity and Humidity on Diethyl Phthalate Adsorption and Desorption on Silicon Surface

The real-time adsorption and desorption of water and diethyl phthalate on silicon surface were studied using a quartz crystal microbalance in ambient nitrogen, having various values of humidity, gas velocity and diethyl phthalate concentration. In a steady state, the adsorbed amount of water and diethyl phthalate is considered to depend only on each concentration in the ambient nitrogen. However, in a non-steady state, the gas velocity at the quartz crystal microbalance enhances both the adsorption rate and the desorption rate. Therefore, the gas velocity at the measurement point is concluded to be one of the key parameters that influence the organic contamination measurement.