= Adhesion
{wiki}
<Adhesion> is attraction between different surfaces that can keep them attached after a compressive contact load is removed. It can arise from <intermolecular forces> or other interfacial interactions; a <liquid> bridge can also contribute a capillary <force>. The work needed to reversibly separate a unit <area> is an interfacial <energy>, whereas the measured <pull-off force> depends additionally on geometry and <elastic deformation>.
Pressing a spherical probe onto a specimen and then retracting it provides a direct test. Contact may persist while the apparatus reads a tensile <force>; detachment occurs only when that adhesive contact becomes unstable. <Hertzian contact> cannot describe this tensile branch because it neglects <adhesion>. Surface contamination, roughness and humidity can change a measurement even when the bulk <Young's modulus> stays fixed. This makes preparation of the interface as important as calibration of the force probe when comparing adhesive response.
Back to article page
