Mapping the local Young's modulus by analysis of the elastic deformations occurring in atomic force microscopy

The atomic force microscope (AFM) is used to map the local elastic properties of substrates by analysis of the force versus tip motion curves. Measurements are presented, which show that gold islands on a rough polypropylene substrate can be distinguished from the surrounding polymer. Quantitative calculations of the elastic deformations of the tip and of the sample, as induced by the AFM, were performed. Surprisingly, the tip deformation is predominant over the sample deformation in a wide regime of forces and of tip radii; which are commonly used in AFM. This fact limits the capability of the AFM to measure local elastic properties. However, with our experimental set-up one can induce a total deformation dominated by the sample deformations.

[1]  Harry Heinzelmann,et al.  Atomic force microscopy for the study of tribology and adhesion , 1989 .

[2]  M. Radmacher,et al.  From molecules to cells: imaging soft samples with the atomic force microscope. , 1992, Science.

[3]  I. L. Singer,et al.  Fundamentals of friction : macroscopic and microscopic processes , 1992 .

[4]  Sidney R. Cohen,et al.  Nanomechanics of a Au–Ir contact using a bidirectional atomic force microscope , 1990 .

[5]  G. Binnig,et al.  True Atomic Resolution by Atomic Force Microscopy Through Repulsive and Attractive Forces , 1993, Science.

[6]  C. Mathew Mate,et al.  Atomic force microscopy of polymeric liquid films , 1989 .

[7]  S. Magonov,et al.  Interpreting STM and AFM Images , 1994 .

[8]  K. Kendall,et al.  Surface energy and the contact of elastic solids , 1971, Proceedings of the Royal Society of London. A. Mathematical and Physical Sciences.

[9]  L. Schlapbach,et al.  New Aspects in Volmer-Weber 3d Growth - an Xps Intensity Study Applied to Thin-Films of Au and Ce on Polypropylene , 1994 .

[10]  Sandor Kasas,et al.  Deformation and height anomaly of soft surfaces studied with an AFM , 1993 .

[11]  R. Overney,et al.  Elastic Compliances Measured by Atomic Force Microscopy , 1994 .

[12]  D. Tománek,et al.  Theory of elastic tip–surface interactions in atomic force microscopy , 1991 .

[13]  Burnham,et al.  Probing the surface forces of monolayer films with an atomic-force microscope. , 1990, Physical review letters.

[14]  Blackman,et al.  Interaction forces of a sharp tungsten tip with molecular films on silicon surfaces. , 1990, Physical review letters.

[15]  I. N. Sneddon.  The relation between load and penetration in the axisymmetric boussinesq problem for a punch of arbitrary profile , 1965 .

[16]  George M. Pharr,et al.  Measurement of Thin Film Mechanical Properties Using Nanoindentation , 1992 .

[17]  J. Israelachvili.  Intermolecular and surface forces , 1985 .

[18]  Hubert M. Pollock,et al.  Interpretation of force curves in force microscopy , 1993 .

[19]  Hubert M. Pollock,et al.  Interpretation issues in force microscopy , 1991 .

[20]  Hertz.  On the Contact of Elastic Solids , 1882 .

[21]  Pohl,et al.  Observation of metallic adhesion using the scanning tunneling microscope. , 1990, Physical review letters.