The role of the backing layer in the mechanical properties of micrometer-scale fibrillar structures

Abstract

The contact mechanics of a micro-fabricated fibrillar surface structure made of poly(dimethylsiloxane) (PDMS) was studied in this work. The attachment and detachment of individual fibrils to and from a spherical indenter upon approach and retraction are detected as jumps in force and stiffness. A quantitative model describes the jumps in stiffness values by taking into account the deformation of the backing layer. The results emphasize the importance of long-range interactions in the contact mechanics of elastic materials and confirm the concepts underlying the development of fibrillar adhesive materials.