  A model of charge hopping transport that accounts for anisotropy of localized
states and Coulomb interaction between charges is proposed. For the anisotropic
localized states the degree of orientation relates exponentially to the ratio
of conductivities in parallel and perpendicular directions, while the ratio of
Seebeck coefficients stays nearly unaffected. However, the ratio of Seebeck
coefficients increases if Coulomb interaction is screened stronger in a
direction parallel to the predominant orientation of the localized states. This
implies two different physical mechanisms responsible for the anisotropy of
thermoelectric properties in the hopping regime: electronic state localization
for conductivities, and screening for Seebeck coefficients. This provides
explanation for recent experimental findings on tensile drawn and ribbed
polymer films.
