液体环境下接触共振原子力显微术探针动力学行为研究  

Study on the Dynamic Behaviors in Contact Resonance Atomic Force Microscopy in Liquid Environments

作　　者：杨长运 周锡龙 张帮志[1] Changyun Yang;Xilong Zhou;Bangzhi Zhang(College of Energy and Mining Engineering,Shandong University of Science and Technology,Qingdao,266590;Hubei Key Laboratory of Theory and Application of Advanced Materials Mechanics,Wuhan University of Technology,Wuhan,430070)

机构地区：[1]山东科技大学能源与矿业工程学院,青岛266590 [2]武汉理工大学新材料力学理论与应用湖北省重点实验室,武汉430070

出　　处：《固体力学学报》2024年第5期694-708,共15页Chinese Journal of Solid Mechanics

基　　金：新材料力学理论与应用湖北省重点实验室开放基金项目(TAM202205)资助。

摘　　要：接触共振原子力显微术是材料微纳米尺度力学性能测试的有力工具,可用于大气和液体环境.接触共振原子力显微术在液体环境下工作时,探针同时受到微悬臂-流体-样品之间的流固耦合作用以及针尖与样品相互作用,使得液体环境下探针微悬臂动力学特性与真空环境下有显著差异.本文将流体对探针微悬臂的影响等效为附加质量及附加阻尼,研究了液体环境下流体密度和粘度对其动力学特性的影响,以及针尖样品接触刚度和接触阻尼对其动力学特性的影响.结果表明,与液体粘度相比,液体环境下流体密度对微悬臂固有频率影响占主导地位;与液体密度相比,流体粘度对微悬臂品质因子影响占主导地位;探针高阶模态对于流体粘度和密度变化具有更高的灵敏度;随着液体环境下针尖样品接触刚度的增加,高阶模态对高接触刚度具有更高的灵敏度;低阶模态对于接触阻尼变化的灵敏度更高.此外,对微悬臂在不同激励方式下的动力学响应进行了对比研究,给出了液体环境不同激励方式下微悬臂动力学响应差异的原因.论文研究结果对于开展液体环境下接触共振原子力显微术微纳米力学成像,提高测量准确度和灵敏度具有重要指导意义.Contact resonance atomic force microscopy(CR-AFM)is a powerful technique that enables the measurement of topography and the mechanical properties of various materials at the micro/nanoscale.It can be used in both air and liquid environments.However,when CR-AFM is operated in a liquid environment,the dynamic behaviors of the microcantilever can be significantly different from those in air or vacuum due to the complex fluid-solid coupling of the microcantilever-liquid-sample system and the tip-sample interaction.In this study,we explore the effects of liquid density and viscosity,as well as tip-sample normalized contact stiffness and contact damping,on the dynamics of the AFM microcantilever in liquid environments.We treat the influence of the liquid on the dynamics of the AFM microcantilever as added mass and added damping.Our results show that in free vibration,the natural frequencies of the AFM microcantilever are primarily dominated by the liquid density,while the liquid viscosity plays a dominant role in the quality factor compared to the liquid density.Higher modes exhibit higher sensitivity to changes in liquid viscosity and liquid density.As the normalized tip-sample contact stiffness increases,a higher mode shows increased sensitivity to changes in normalized contact stiffness in a liquid environment.On the other hand,a lower mode is more sensitive to changes in normalized contact damping in a liquid environment.In addition,the dynamic responses of the AFM microcantilever under three different excitation approaches are compared and discussed.Variations in boundary conditions and hydrodynamic loads applied to the microcantilever under these approaches lead to diverse dynamic responses.The findings in this study are essential for the development of micro/nanoscale mechanical property imaging techniques using CR-AFM in liquid environments,as well as the improvement of measurement accuracy and sensitivity.

关 键 词：接触共振 微悬臂 流固耦合 复频率 动力学分析 

分 类 号：TH742[机械工程—光学工程]