Calibration of Friction Force Signals in Atomic Force Microscopy in Liquid Media

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• 作者：Ewa Tocha ; Jing Song ; Holger Sch&ouml ; nherr ; G. Julius Vancso
• 刊名：Langmuir
• 出版年：2007
• 出版时间：June 19, 2007
• 年：2007
• 卷：23
• 期：13
• 页码：7078 - 7082
• 全文大小：150K
• 年卷期：v.23,no.13(June 19, 2007)
• ISSN：1520-5827

文摘

The calibration factors for atomic force microscopy (AFM) friction force measurements in liquid media are shownto be different by 25-74% compared to measurements in air. Even though it is significantly more precise, the improvedwedge calibration method using a universal calibration specimen suffers, as all other widely applied methods, fromthe drawback that friction force calibration factors acquired in air cannot be used for measurements in liquids for themost common liquid cell designs. The effect of laser light refraction and the dependence of the calibration factorson the refractive index of the imaging medium is captured quantitatively in a simple model that allows one toconveniently rescale the values of lateral photodiode sensitivity obtained in air. Hence a simple, yet precise calibrationof lateral forces is now also feasible for AFM in liquids.