AVS 47th International Symposium
    Nanotubes - Science and Applications Monday Sessions
       Session NM+NS-MoM

Paper NM+NS-MoM6
Local Solvation Shell Measurement in Water using a Carbon Nanotube Probe

Monday, October 2, 2000, 10:00 am, Room 309

Session: Carbon Nanotubes: Functionalization and Applications
Presenter: H. Tokumoto, JRCAT-NAIR, Japan
Authors: S.P. Jarvis, JRCAT-NAIR, Japan
T. Uchihashi, JRCAT-ATP, Japan
H. Tokumoto, JRCAT-NAIR, Japan
Correspondent: Click to Email
Oscillatory forces between two approaching surfaces in solvent have long been the subject of study due to their possible influence on any surface-surface interactions mediated through a liquid or in the presence of a fluid film. Of particular interest is water, due to its omnipresence in all but the most stringently controlled environments and its role as the primary medium for biological interactions. Combining a carbon nanotube probe with an AFM has enabled us to measure oscillatory forces in water on approaching a surface that has been laterally characterized on a nanometer scale. One important aspect of the utilization of carbon nanotubes as the AFM probe is to remove the unwanted hydrodynamic damping effect caused by the bulk of the tip. We used a multi-walled carbon nanotube attached to a PtIr coated silicon lever in a specially designed FE-SEM. Another aspect is the usage of a magnetically activated AFM, which has been possible to resolve molecular layers of large molecules. With this method, magnetic material is deposited directly behind an AFM tip on the back-side of the cantilever so that the tip position can be controlled by the addition of a magnetic field. The lever can be vibrated in an oscillating magnetic field in order to make dynamic measurements. This success opens up the possibility of investigating water layers under a variety of experimental conditions and as a function of precise lateral position on any surface including biological membranes and macromolecules. Among the many and varied roles of water layers are effects on biomolecular adhesion, colloid dispersion and tribology, which can now be investigated with nanometer lateral resolution.