  A pronounced irreversible electro-optical response (memory effect) has been
recently observed for nematic liquid crystal (LC) EBBA doped by multi-walled
carbon nanotubes (MWCNTs) near the percolation threshold of the MWCNTs
(0.02-0.05 wt. %). It is caused by irreversible homeotropic-to-planar
reorientation of LC in an electric field. This feature is explained by
electro-hydrodynamically stimulated dispergation of MWCNTs in LC and by the
formation of a percolation MWCNT network which acts as a spatially distributed
surface stabilizing the planar state of the LC. This mechanism is confirmed by
the absence of memory in the EBBA/MWCNT composites, whose original structure is
fixed by a polymer. The observed effect suggests new operation modes for the
memory type and bistable LC devices, as well as a method for \textit{in situ}
dispergation of carbon nanotubes in LC cells.
