Stefan adhesion is the stress (force per area) between two disks. Stefan's law governs the flow of polymer between the solid parallel plates. If a downward force ${\displaystyle F}$ is applied to separate two disks of radius ${\displaystyle R}$ in a viscous polymer with viscosity ${\displaystyle \eta }$ and height ${\displaystyle h}$ that varies with time ${\displaystyle t}$;
${\displaystyle F={\frac {3\pi R^{2}}{2h(t)^{3}}}{\frac {dh}{dt}}\eta }$