A non-destructive method to calibrate the torsional spring constant of atomic force microscope cantilevers in viscous environments
A non-destructive method to calibrate the torsional spring constant of atomic force microscope cantilevers in viscous environments
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DOI：
10.1063/1.5046648
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发表时间：
2018-10-21
影响因子：
3.2
通讯作者：
Voitchovsky, Kislon
中科院分区：
文献类型：
--
作者：
Cafolla, Clodomiro;Payam, Amir F.;Voitchovsky, Kislon
从纳米级摩擦和润滑测量到微机电系统的表征以及生物分子对外部刺激的响应，原子力显微镜杠杆的扭转弹簧常数的校准对于一系列应用是至关重要的。现有的校准方法要么是耗时和破坏性的（非原位静态方法），或依赖于使用悬臂梁扭转共振的频率和品质因数（Q因子）作为输入参数的模型（原位动态方法）。虽然原位方法通常是首选的，因为它们易于实施和保存悬臂，但它们对扭转共振Q因子的依赖使得在高粘性环境中的校准具有挑战性。例如，在许多纳米级摩擦学应用中，这是有问题的。在这里，我们提出了一种校准方法，不依赖于悬臂梁的扭转Q因子，并显示如何悬臂挠度可以转换为横向力。该方法进行了测试与六个不同形状和材料成分的杠杆，并在六种流体介质。导出的弹簧常数与现有方法的预测相比，表现出更高的精度，特别是对于高粘度液体。(C)2018年作者。所有文章内容，除非另有说明，是根据知识共享署名（CC BY）许可证许可。
Calibration of the torsional spring constant of atomic force microscopy cantilevers is fundamental to a range of applications, from nanoscale friction and lubrication measurements to the characterization of micro-electromechanical systems and the response of biomolecules to external stimuli. Existing calibration methods are either time consuming and destructive (ex situ static approaches), or rely on models using the frequency and quality factor (Q-factor) of the cantilever torsional resonance as input parameters (in situ dynamical approaches). While in situ approaches are usually preferred for their easy implementation and preservation of the cantilever, their dependence on the torsional resonance Q-factor renders calibration in highly viscous environments challenging. This is problematic, for example, in many nanoscale tribological applications. Here, we propose a calibration method that does not depend on the cantilever torsional Q-factor and show how the cantilever deflection can be converted into a lateral force. The method is tested with six cantilevers of different shapes and material composition and in six fluid media. The derived spring constants are compared with predictions from existing methods, demonstrating a higher precision, in particular, for highly viscous liquids. (C) 2018 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license.