For the purpose of preparing TCCs (= transparent and electrical conducting
coatings), metallic and ferromagnetic nano-additives were dispersed into a
transparent varnish and the obtained dispersions were coated on transparent
plastic substrates. During hardening of the dispersion the magnetic nano-
additives were aligned by a magnetic field. The resulting coatings have
electrical pathways along lines of nano-additive chains and are highly
transparent in the areas between the lines. Therefore, the electrical
conductivity is anisotropic, and it depends on the alignment of the nano-
additives (i.e. on the distance between the nano-additives within the chains
and the length of the lines) as well as on the thickness of an oxide and/or
solvent shell around the nano-additives. The transparency depends also on the
alignment and here especially on the thickness and the distance between the
formed lines. The quality of the alignment in turn, depends on the magnetic
properties and on the size of the particles. We used commercial plastic
varnishes, which form electrically isolating (≥ 10− 12 S/m) and transparent
(about 90% transparency) coatings, and the following magnetic additives: Co-,
Fe-, CoPt3, CoPt3@Au- and Fe@Au-nanoparticles as well as CoNi-nanowires.
Coatings with Fe@Au-nanoparticles show the best results in terms of the
electrical conductivity (10− 5 S/m–10− 6 S/m) at transparencies above 70%.
Furthermore, in addition to the magnetic nano-additives, transparent additives
(Al2O3-particles) and non-magnetic, but better conducting additives (carbon-
nanotubes) were added to the varnish to increase the transparency and the
electrical conductivity, respectively