  We review existing manifestations and prospects for ferroelectricity in
electronically and optically active carbon-based materials. The focus point is
the proposal for the electronic ferroelectricity in conjugated polymers from
the family of substituted polyacetylenes. The attractive feature of synthetic
organic ferroelectrics is a very high polarizability coming from redistribution
of the electronic density, rather than from conventional displacements of ions.
Next fortunate peculiarity is the symmetry determined predictable design of
perspective materials. The macroscopic electric polarization follows ultimately
from combination of two types of a microscopic symmetry breaking which are
ubiquitous to qusi-1D electronic systems. The state supports anomalous
quasi-particles - microscopic solitons, carrying non-integer electric charges,
which here play the role of nano-scale nucleus of ferroelectric domain walls.
Their spectroscopic features in optics can interfere with low-frequency
ferroelectric repolarization providing new accesses and applications. In
addition to already existing electronic ferroelectricity in organic crystals
and donor-acceptor chains, we point to a class of conducting polymers and may
be also to nano-ribbons of the graphene where such a state can be found. These
proposals may lead to potential applications in modern intensive searches of
carbon ferroelectrics.
