The contact mechanics-based Johnson−Kendall−Roberts technique has been used to study the adhesion
of cross-linked 2-ethylhexyl acrylate-co-acrylic acid (2EHA-co-AA) elastomers as models of pressure sensitive
adhesives (m-PSA). We have addressed the effect of m-PSA composition on intrinsic solid surface energetics
and on the mechanical performance of m-PSA. The measured surface energies of the m-PSA were all
approximately 30 mJ m-2, indicating surfaces dominated by methylene groups. The extent of adhesion
hysteresis for the m-PSA used in our measurements was not a strong function of acrylic acid content
implying that the main mechanism contributing to the adhesion of practical un-cross-linked or lightly
cross-linked PSA is the viscoelastic dissipation. Several technical and physical issues concerning contact
mechanical measurement of adhesion and the observed rate-dependent patterns of adhesion have been
addressed.