Purpose

During atomic force microscope operation, electrostatic, capillary, and van der Waals forces contribute significantly to AFM tip–sample interaction. This paper presents the effects of probe retracting velocities on the tip–sample interaction and reveals the discrepancies of the interaction measured from the surfaces of different hardness and wettability.

Methods

In this work, the effects of retracting velocities on probe vibration were studied by simultaneously investigating variation of the force, amplitude, and phase with vertical displacement (f–d, a–d and p–d curves) upon AFM tip leaving a silicon surface. The same measurement was also conducted on the samples of different hardness and wettability to investigate their effects on the interaction.

Results

It is found that the slopes of the f–d, a–d or p–d curves decrease with the increase of retracting velocity. In addition, the slope of the a–d curve collected on the hydrophilic silicon surface presents an abrupt change during the amplitude increase. Besides, the amplitude and phase have a long changing process with probe displacement when the probe is retracted from a polyvinyl chloride surface.

Conclusion

The results indicate that the increase in the velocity causes the tip–sample interaction to decrease more slowly with the probe displacement, and the interaction is greater as the probe retracts from soft or hydrophilic surface under the same conditions. The study provides an opportunity for deeper understanding tip–sample interaction and may shed new light on comparing the hardness and wettability of materials through investigating AFM probe vibrations.

中文翻译：

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收缩速度对原子力显微镜探针在不同表面上振动的影响

目的

在原子力显微镜操作过程中，静电力，毛细管力和范德华力对AFM针尖与样品的相互作用起很大作用。本文介绍了探针回缩速度对尖端与样品相互作用的影响，并揭示了从不同硬度和润湿性的表面测得的相互作用差异。

方法

在这项工作中，通过同时调查力，振幅和相位随AFM尖端离开硅表面的垂直位移（f – d，a – d和p – d曲线）的变化，研究了回缩速度对探头振动的影响。。还对不同硬度和润湿性的样品进行了相同的测量，以研究它们对相互作用的影响。

结果

结果表明，f – d，a – d或p – d曲线的斜率随回缩速度的增加而减小。此外，在亲水性硅表面上收集的a – d曲线的斜率在幅度增加期间呈现出突变。此外，当探头从聚氯乙烯表面缩回时，幅度和相位会随着探头的位移而发生长时间的变化过程。

结论

结果表明，在相同条件下，速度的增加会导致尖端与样品之间的相互作用随着探针的位移而减慢，而随着探针从柔软或亲水的表面缩回，相互作用会更大。这项研究为深入了解针尖与样品之间的相互作用提供了机会，并可能通过调查AFM探头的振动，为比较材料的硬度和可湿性提供新的思路。