Scanning force microscopy jumping and tapping modes in liquids

In this work theoretical considerations of the performance of scanning force microscopy jumping mode and tapping mode in liquids are discussed. A priori, jumping mode should improve in a liquid environment compared to in air while the situation for tapping mode should become worse. In order to confirm this we present jumping and tapping mode images of DNA molecules absorbed on a mica substrate immersed in water. The experiments demonstrate that jumping mode is a suitable scanning force microscopy method by which to image soft samples in liquid and that it has similar or even better performance than those exhibited by tapping, but without the complex experimental requirements of this mode. (C) 2002 American Institute of Physics.