90 HIGH PERFORMANCE POLYMERS
with a nucleophilic compound. Several examples of
the conversion have been detailed [151].
3.5.5 Poly(p-phenylenevinylene)
Nanofibers
PPV nanofibers can be produced by electrospinning
a PPV precursor polymer from an alcohol solution.
Electrospinning uses an electrical charge to form fine
fibers. Electrospinning is similar to electrospraying.
A polymer solutionis ejected through a fine needle that
is electrically charged. The charges cause the droplet
to stretch. If the viscosity of the droplet is sufficiently
high, the droplets are not sprayed as it occurs in the
electrospray technique, but a liquid jet is formed. Volt-
ages in the range of 10 kV are applied. After annealing
at 180
◦
C for 2 h, the PPV precursor polymer is trans-
formed ...