  We combine new (NGC 1275, NGC 4151, and NGC 5506) and previously published
(Cygnus A, Mrk 231, and NGC 1068) sub-arcsecond resolution mid-infrared (MIR;
8-13 $\mu$m) imaging- and spectro-polarimetric observations of six Seyfert
galaxies using CanariCam on the 10.4-m Gran Telescopio CANARIAS. These
observations reveal a diverse set of physical processes responsible for the
nuclear polarization, and permit characterization of the origin of the MIR
nuclear polarimetric signature of active galactic nuclei (AGN). For all radio
quiet objects, we found that the nuclear polarization is low (<1 per cent), and
the degree of polarization is often a few per cent over extended regions of the
host galaxy where we have sensitivity to detect such extended emission (i.e.,
NGC 1068 and NGC 4151). We suggest that the higher degree of polarization
previously found in lower resolution data arises only on the
larger-than-nuclear scales. Only the radio-loud Cygnus A exhibits significant
nuclear polarization ($\sim$11 per cent), attributable to synchrotron emission
from the pc-scale jet close to the core. We present polarization models that
suggest that the MIR nuclear polarization for highly obscured objects arises
from a self-absorbed MIR polarized clumpy torus and/or dichroism from the host
galaxy, while for unabsorbed cores, MIR polarization arises from dust
scattering in the torus and/or surrounding nuclear dust.
