Actuation of atomic force microscope cantilevers in fluids using acoustic radiation pressure

Actuation of microcantilevers in fluids has applications such as atomic force microscopy, fluid mixing and mechanical property characterization in microchannels. In this paper of a microfluidic actuator, which utilizes acoustic radiation pressure (ARP) to exert DC and AC forces on a microcantilever is discussed. An atomic force microscope (AFM) cantilever has been used to demonstrate the capabilities of this actuator. The method allows the application of a localized force at a desired location on a cantilever with a 5 MHz bandwidth. The localized nature of the applied force allows the characterization of flexural and torsional oscillation modes of the AFM cantilevers. Tapping mode atomic force microscopy was also carried out using the ARP actuator.