Among AFM microscopes, Dynamic force microscopes (DFM) are very sensitive to variation of minute forces involved in the interaction between the tip and the surface. However, despite numerous efforts, imaging and probing mechanical properties of soft materials in air and water at the nm scale are still challenging experiments or at least cannot be achieved routinely. Among various factors determining AFM efficiency, AFM tip remains the central parameter and have been the focus of many creative conceptions and experimental attempts to improve its stability and resolution.
Therefore any new developments able to improve the geometry and size of AFM tips were systematically investigated, in particular use of Carbon Nanotube (CNT), etching process, or Focus Ion Beam to carve a tip. In that talk we review few results obtained on single and multi wall CNT used as AFM tip apex. In particular we focus on the mechanical properties of CNT and highlight the competition between CNT adhesion to substrate and CNT elastic force.
The second part of the presentation is dedicated to the study of the air-liquid interface. We discuss the physical properties of a nanomeniscus wetting an oscillating nanoneedle. The results address questions concerning stability and behaviour of attolitter drops at the triple line frontier and properties of laminar flows at the nanometer scale. Also we show the ability to control and record image at the air-liquid interface. The present work shows the capability to investigate change of the surface tension at nanometer scale for more complex liquid interfaces.
- D. Dietzel et al '"Mechanical properties of a carbon nanotube fixed at a tip apex'" Physical Review B 72, 035445 (2005). Nanotechnology 16, p.S73-S78 (2005)
- C. Jai et al “Wetting an oscillating Nanoneedle: dynamical behaviour of a Nanomeniscus.” Submitted.
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