Particles
suspended in a solution often carry a net charge. Under the
influence of a dc electric field (20-1000 V/cm) these charged particles
move towards
the oppsitely charged electrode and get deposited as film. These
films are essentially a 3-D assembly of particles and thus possess a
nanostructured morphology. This simple method of casting film has
been widely employed in our laboratory to obtain nanostructured films
of metal (gold, platinum), semiconductors fullerene, porphyrin and
carbon nanotubes.
See A Video demonstration
Examples of electrophoretically deposited C60, CdSe and C60-CdSe films on conducting glass are shown below.
Note that these
experiments should be conducted in a nonpolar solvent
medium and should not involve oxidation or reduction processes at the
electrodes. If you see any bubble formation at the
electrodes, probably electrolysis
is occuring and it is an indication that the applied voltage is too
high. The electrophoresis provides electric field
to drive the charged particles from solution towards the electrode
surface and thus differs from the commonly used electrodeposition
process. As always use precaution with high voltage power supplies
while making connections.