Atomic force microscope based two-dimensional assembly of micro/nanoparticles

This research aims at achieving two-dimensional micro/nanomanipulation and assembly of micro/nanoscale particles using atomic force microscope (AFM). Unlike prior works, the presented manipulation models include friction models based on both the normal forces as well as the adhesion forces. Pull-off forces are modeled using the Johnson-Kendall-Roberts (JKR) contact mechanics model. This model is used to determine whether critical conditions for particle motion are achieved. Pushing manipulation experiments are performed on polystyrene microparticles. A top-view high resolution optical microscope, used for probe and particle position and motion detection, facilitated real-time visual feedback. A piezoelectric XYZ positioning stage with few nanometers precision enabled the two-dimensional precise assembly of the polystyrene microparticles. Using the real-time visual feedback, the behavior of particles manipulated by an AFM probe, is investigated. The results from the experiments matched those from the simulation, successfully verifying the developed models. The modeling, simulation and the experiments have enhanced the understanding of the interaction forces at the micro/nanoscale during micro/nanoassembly and particle manipulation