Directional Triboelectric Effect in Keratin Fibers

The difference between the electrochemical potentials of the contacting surfaces is generally accepted as the driving force behind the generation of static charges [3, 4; 9]. The key parameter is the work function ~, which, for metals, is defined as the work required to remove the electrons from the Fermi level (energy of electrons at 0 K) to the surface. For polymers, where no discrete energy bands exist, it is derived from the concept of localized states. The electrochemical potential (p) of the material can be thus expressed as: