Muralidharan G, Wig A, Pinnaduwage L A, Hedden D, Thundat T, Lareau Richard T
Oak Ridge National Laboratory, Life Sciences Division, Oak Ridge, TN 37831 6123, USA.
Ultramicroscopy. 2003 Oct-Nov;97(1-4):433-9. doi: 10.1016/S0304-3991(03)00071-8.
Understanding the kinetics of adsorption and desorption of explosive vapors such as TNT from surfaces is important in the design of sensors. We report for the first time, the adsorption-desorption characteristics of TNT from a Si-microcantilever exposed to vapors of TNT. It was observed that TNT readily sticks to the exposed Si surface with the adsorption kinetics showing an initial exponential behavior followed by roughly linear kinetics. It was also observed that for cantilever temperatures close to room temperature, TNT desorbs spontaneously from the surface with decaying exponential kinetics. Based on the known equilibrium partial vapor pressures of TNT, the "effective" sticking coefficient for the silicon oxide surface at room temperature under the experimental conditions was calculated to be about 0.02. This information can be very useful in the design of sensors and that of vapor-delivery systems.
了解诸如TNT等爆炸性蒸汽在表面的吸附和解吸动力学对于传感器设计至关重要。我们首次报道了TNT从暴露于TNT蒸汽的硅微悬臂梁上的吸附-解吸特性。据观察，TNT很容易附着在暴露的硅表面，吸附动力学呈现出初始指数行为，随后大致呈线性动力学。还观察到，对于接近室温的悬臂梁温度，TNT以衰减指数动力学从表面自发解吸。根据已知的TNT平衡蒸汽分压，计算出实验条件下室温下氧化硅表面的“有效”粘附系数约为0.02。这些信息在传感器设计和蒸汽输送系统设计中可能非常有用。
