Surface imaging of fragile materials with hydrophobic atomic force microscope tips

In ambient air, the quality of atomic force microscope (AFM) images can be strongly affected by the capillary effect due to the formation of water meniscus between the AFM Si3N4 tips and the substrates. In view of this, we performed a direct surface modification of the bare tips using a self-assembled monolayer (SAM) of octadecyltrichlorosilane (OTS) to make the tips hydrophobic and eliminate this effect. The images, when collected with the thus obtained modified tips, showed improved performance of tips not only for hard samples but also for fragile systems. This investigation implies a chemical tip modification method to image samples with high resolution in air, by means of making the bare tips hydrophobic.