  The Navier slip boundary condition is interpreted as an equilibrium of shear
rate and slip rate. From the argument that the slip rate shall be proportional
to the molecules' collision rate, the temperature dependence of the Navier slip
boundary condition is derived. The model for the temperature dependence of the
slip length is validated by slip measurements of liquid hydrocarbons in a novel
Couette typ tribometer being introduced. The essence of the gained experimental
data for one fluid-solid-interface is the quadruple activation energy for shear
and wall slip together with the viscosity and slip length at a reference
temperature. This quadruple is determined for four different hydrocarbon
liquids of different molecular mass, structure and polarity proving the
applicability of the new measurement method. From the executed systematic
measurements three conclusions regarding the slip length dependence are pointed
out: (i) the slip length increases with increasing molar mass; (ii) changing
the molecular structure from saturated hydrocarbon to unsaturated affects the
slip length as well as the activation energy for slip; (iii) adding a small
fraction of polar molecules to the hydrocarbon decreases the slip length and
increases the activation energy for wall slip due to the polar end-groups of
the liquid.
