Attachment of nanoparticles to the AFM tips for direct measurements of interaction between a single nanoparticle and surfaces

Here we report a universal method of attachment/functionalization of tips for atomic force microscope (AFM) with nanoparticles. The particles of interest are glued to the AFM tip with epoxy. While the gluing of micron size particles with epoxy has been known, attachment of nanoparticles was a problem. The suggested method can be used for attachment of virtually any solid nanoparticles. Approximately every other tip prepared with this method has a single nanoparticle terminated apex. We demonstrate the force measurements between a single ∼50 nm∼50 nm ceria nanoparticle and flat silica surface in aqueous media of different acidity (pH 4–9). Comparing forces measured with larger ceria particles (∼500 nm∼500 nm), we show that the interaction with nanoparticles is qualitatively different from the interaction with larger particles.

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