  The dipoles in ferroelectric copolymer P(VDF-TrFE) can be driven by electric
field, introducing phonon transport modulations through polarizing molecular
chains. The thermal conductivity in single 75/25 P(VDF-TrFE) nanofibers is
found to increase with electric field related phonon renormalization, resulted
from change in vibrational assignment excited by polarization process. This is
evidenced by a direct change of bond energy and bond length in 75/25
P(VDF-TrFE) nanofibers from Raman characterization under polarization electric
field. The experimental results provide further intuitive evidences that the
size of ferroelectric polymers could directly affect the ferroelectricity from
the size-dependent thermal transport measurement.
