Torsional resonance atomic force microscopy in water

An atomic force microscope for use in liquids including water, in which a torsionally resonating microcantilever controls the tip-sample interaction, is presented. Magnetostrictive actuators made from a particulate composite of Terfenol-D are used to excite the torsional oscillations of the cantilever. The high quality factor (Q) of torsional oscillation gives high sensitivity to tip-sample forces, and the ability to work using the true resonance peak of the cantilever allows “phase” images corresponding to real mechanical contrast to be collected under liquid. High quality topographic and phase images of a delicate crystallizing polymer sample submerged in water are presented.