Paper NS-MoM9
Design and Realization of 3D Printed AFM Probes

Monday, November 7, 2016, 11:00 am, Room 101D

Atomic force microscopy (AFM) is an enabling tool for nanoscience due to its ability to image surfaces with sub-nanometer resolution. One drawback, however, is that the AFM probe must be chosen to complement the material properties of the system of interest – e.g. stiff probes are ideal for imaging hard surfaces while soft probes are needed for softer biological materials. Furthermore, the conventional lithography techniques that are used to fabricate AFM probes can only generate limited architectures from a narrow subset of materials. In analogy to the impact rapid prototyping has made on macroscopic manufacturing, nanoscale 3D printing can in principle be used to construct AFM probes in a manner that allows important properties such as spring constant and vibrational resonance frequency to be rationally chosen. Moreover, since it is possible to fully control the 3D structure of a probe, additional properties such as higher harmonic resonance frequencies and deflection sensitivity can be independently adjusted. Here, we demonstrate that functioning AFM cantilevers that are compatible with commercial AFM systems can be 3D printed and used for imaging. In particular, a series of bisegmented probes with consistent spring constants but different resonance frequencies were designed, printed, and evaluated using an AFM. Their properties were found to be consistent with finite element mechanical simulations and comparable to commercially available probes. In addition, we found that the second harmonic mode could be tuned to an integer multiple of the principle harmonic, in a manner that could provide multimode imaging with resonance enhancement. This work opens the door for complex non-rectilinear cantilevers that provide uniquely tuned force-distance relationships or harmonic behavior.