Development of Measuring Method of Interaction Force between Surfaces with Atomic Force Microscope

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1.Evaluation of Shape of Probe Tip of Atomic Force Microscope and Improvement of ImagesImages of materials, such as particles, generated by Atomic Force Microscope (AFM) are strongly influenced by the shape and angle of the tip. Using a spherical particle for the calibration, the detailed shape and radius of curvature of the tip were successfully estimated, and the method to obtain improved sample image was established.2.Development of Colloid CantileverA method to glue a sherical particle on the probe tip of AFM with epoxy resin was established. This probe enable us to measure directly the interaction forces between surfaces of a particle and a flat plate and also between two particles.3.Measurement of Interaction ForceUsing the cantilever developed in this work, the interaction forces between a mica plate and a particle and between a mica plate and a probe tip were measured.<Aqueous system> The DLVO theory for the interaction force in electrolyte solution was confirmed experimentally. The additional repulsive force related with the hydration force was measured when two surfaces were close. The adhesive force was successfully related with the hydration of adsorbed cations on the interface and the structure of molecules adsorbed on the surface.<Non-aqueous system> In order to develop a theory of interaction forces between surfaces in non-aqueous systems, the interaction forces in alcohol aqueous solutions were investigated and the region where DLVO theory was applicable was clarified. It was found that the deviation from the DLVO theory was attributable to the permittivity and molecular sizes of solutions. The correlation between the structure of molecules adsorbed on the surface and the adhesive force were also clarified.<Magnetic effects> The ordering of molecules adsorbed on a surface by the magnetic exposure was examined using AFM and the existence of the magnetic effects was confirmed on the molecular level.