Oxireductases in the Enzymatic Synthesis of Water-Soluble Conducting Polymers - Enzymatic Polymerisation - page 13

Enzymatically synthesized
PEDOT/PSSNa
PEDOT/PSS (from Aldrich)

1600 1400 1200 1000 800

Wavenumber (cm -1 )

Fig. 9 IR spectra of commercial PDOT/PSSNa and enzymatically synthesized PEDOT/PSSNa.
(Reprinted with permission from Nagarajan et al. [ 44 ]. c 2008, American Chemical Society)

The FTIR spectrum of the commercially available PEDOT/PSSNa and the en-
zymatically synthesized PEDOT/PSSNa were compared (Fig. 9 ) . The spectra are
scaled individually for clearer comparison. The vibrations at 1195, 1139, and
1089 cm − 1 are due to the C-O-C bond stretch in the ethylenedioxy group. The
peak at 1521 cm − 1 is due to the ring stretching of the thiophene ring. The weak
vibration at 1062 cm − 1 is possibly due to the C-O stretch. Peaks at 979, 937, and
840 cm − 1 are assigned to thiophene C-S bond stretching. As seen in Fig. 3 , the
PEDOT/PSSNa synthesized enzymatically shows similar features to those of the
standard, and no major additional peaks are observed.

5 Biphasic Biocatalytic System for the Synthesis

of Conducting Polymers

The use of enzymes as biocatalysts for the synthesis of water-soluble conducting
polymers is simple, environmentally benign, and gives yields of over 90% due to
the high efficiency of the enzyme catalyst. Since the use of an enzyme solution
does not allow the recovery and reuse of the expensive enzyme, well-established
strategies of enzyme immobilization onto solid supports have been applied to HRP
[ 22 - 30 ]. A recent work reported an alternative method that allows the recycle and
reuse of HRP in the biocatalytic synthesis of ICPs. The method is based on the
use of a biphasic catalytic system in which the enzyme is encapsulated by simple
solubilization into an IL. The main strategy consisted of encapsulating the HRP in
room-temperature ILs insoluble in water, and the other components of the reaction