The current work reports primarily on an experimental This paper reports on an experimental study of the adhesive study, with associated theoretical analyses, of the comprescontact of a single microscopic (about 300 mm) elastomer sphere sive deformation behavior of microscopic elastic polymer compressed between two smooth parallel glass platens at small spheres at a small range-imposed strain in ambient air. For imposed deformations. An experimental arrangement that allows a nonadhesive elastic sphere compressed between two paralthe simultaneous measurement of the compressive displacements lel flat platens, the force resisting this deformation depends and the reaction forces is described. A number of interesting pheupon the approach (half of the compressive displacement at nomena, including the pull-off separation and the ''jump'' contact the pole of the deformed sphere) to the 3/2 power for small phenomena of the microsphere and the moving platen supported by a cantilever, are shown in the experimental force-displacement deformations. The theoretical nature of this relationship was curve of a loading and unloading cycle. The pull-off forces are originally described in detail by Hertz (1) and allows the demonstrated to not depend upon the applied dimensionless apdeformation of the sphere in the region of the contacting proach (compressive displacement/initial particle diameter), platens to be fully described, subject to a number of imwhile they increase with the increasing rate at which the interfaces portant assumptions. The principal assumptions are that a are separated. The predictions of an established contact mechaninormally loaded contact exists between the bodies, that the cal adhesive theory, Johnson-Kendall-Roberts (JKR) theory, in material behaves as a linear elastic body, that the radius of which the influence of the surface energy on the contact has been contact area is small compared with the radius of the sphere, taken into account, are in good agreement with these experimental and that there is frictionless contact between the surfaces results. An application of the JKR analysis to the pull-off force resulting in the transfer of only normal stresses between the provides a reasonable estimate of the interfacial free energy of the contact. แญง 1998 Academic Press contacting surfaces.