液体中基于动态微悬臂梁的质量检测技术  

A Mass Sensing Technology Based on a Dynamic Microcantilever in Liquid

作　　者：房轩[1] 李艳宁[1] 丁丽丽[1] 史晓杰[1] 傅星[1] 胡小唐[1] 

机构地区：[1]天津大学精密测试技术及仪器国家重点实验室,天津300072

出　　处：《压电与声光》2008年第3期379-381,384,共4页Piezoelectrics & Acoustooptics

基　　金：国家自然科学基金资助项目(5030502550675152)

摘　　要：当利用微悬臂梁动态模式的基频谐振在液体环境检测微弱被测量时，液体中的流体动力阻尼导致检测灵敏度降低。针对此问题，提出了利用微悬臂梁的高次谐振进行质量检测的方法。对于相同的被测量质量变化，微悬臂梁的谐振次数越高，其频率偏移越大，从而达到比基频检测法更高的分辨力。以表面修饰三乙基氢硫基十二基铵层（敏感层）的微悬臂梁为传感元件，以CrO4^2-为被测物，在原子力显微镜上检测了敏感层吸附CrO4^2-前后，微悬臂梁的5～8次谐波频率的变化情况。结果显示，该质量检测法能检测出约0．82ng的质量增量。When a resonating microcantilever operates in liquid, owing to the heavy hydrodynamic damping on the microcantilever, the resonant frequency shift is insensitive to effective mass＇ increment, which leads to a very low detection sensitivity. In order to solve this problem, we have developed a new method that is based on a theory that for the same mass＇ increment, the resonant frequency shift is more when a microcantilever is actuated at a higher harmonic. Using an atomic force microscopy as the experiment platform and CrO4^2- ions as the measured object, and a microcantilever with a sensitive layer as a transducer, we detected higher harmonics＇ frequency shift of the micro- cantilever owing CrO4^2- ions adsorbed on the sensitive layer. The result shows a mass＇ increment of 0. 82 ng can be measured by this method .

关 键 词：原子力显微镜 微悬臂梁 动态检测 敏感层 

分 类 号：TN16[电子电信—物理电子学]