A novel polyfluoranthene (PFA) exhibiting strong visual fluorescence emission, a highly amplified quenching
effect, and widely controllable electrical conductivity is synthesized by the direct cationic oxidative
polymerization of fluoranthene in a dynamic interface between n-hexane and nitromethane containing
fluoranthene and FeCl3, respectively. A full characterization of the molecular structure signifies that the
PFAs have a degree of polymerization from 22–50 depending on the polymerization conditions. A
polymerization mechanism at the interface of the hexane/nitromethane biphasic system is proposed.
The conductivity of the PFA is tunable from 6.4 106 to 0.074 S cm1 by doping with HCl or iodine.
The conductivity can be significantly enhanced to 150 S cm1 by heat treatment at 1100 C in argon. A
PFA-based chemosensor shows a highly selective sensitivity for Fe3+ detection which is unaffected by
other common metal ions. The detection of Fe3+ likely involves the synergistic effect of well-distributed
p-conjugated electrons throughout the PFA helical chains that function as both the fluorophore and the
receptor units.