Nanoparticles or similar, nanoscale objects such as proteins or biological fibrils usually have to be deposited from aqueous suspension onto a solid support surface for further characterization by atomic force microscopy (AFM) and related methods such as Kelvin-probe force microscopy (KFM). Here we show, on the examples of functionalized nanoparticles and collagen fibrils, that water desorption after sample preparation affects their electrostatic potential determined by KFM in a predictable manner. We explain this effect with a simple, analytical model based on the capacitance of the partially dielectric-filled tip-sample system. We also propose practical measures to avoid false interpretation of electrical AFM-based experiments. As the phenomenon is very generic it may have significant implications in the application of AFM to nanoparticles and other nanostructures including biological ones.
CITATION STYLE
Mesquida, P., Kohl, D., Bansode, S., Duer, M., & Schitter, G. (2018). Water desorption in Kelvin-probe force microscopy: A generic model. Nanotechnology, 29(50). https://doi.org/10.1088/1361-6528/aae413
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