The secondary alcoholic group of C3?OH. The peak

The FT-IR spectrum (Fig.2A) were carried out to
investigate the surface chemical nature of pristine graphite and exfoliated
graphene. In the spectrum of graphite, the
absorption bands at 3448 cm-1 were
known to be the O-H stretching vibrations, the peak located at 1638 cm-1 could be attributed to the skeletal
vibration of C=C from unoxidized sp2 bonds. After the oxidation reaction,
the FT-IR spectra of GO apparently changed compared to that of graphite. Apart
from the O-H stretching vibrations and skeletal vibration, three new
representative peaks arising from GO could be indexed at           1736 cm-1, 1404 cm-1, 1231cm-1,
which corresponded to the stretching band of C=O in carboxylic acid moieties,
C-OH, C-O-C, respectively. The FT-IR results indicated that oxygen-containing
functional groups were introduced onto the surface of graphite
confirming the successful oxidation of graphite into GO. 29-31. Also,
FT-IR spectrum showed that the sharp characteristic band of the hydroxyl group
at 3448 cm-1 of graphite was shifted to 3428 cm-1 in the case of GO. Chitosan is a well-known
cationic polymer with multi-hydroxyl and amino groups, while GO is negatively
charged with plenty of hydroxyls and epoxides. For chitosan, the peaks at
3437cm?1 are corresponding to the N?H stretching vibration, and
the adsorption peaks at1087cm-1 and 1157cm?1 are
attributed to the primary alcoholic group of C6?OH and the secondary
alcoholic group of C3?OH. The peak at 1637cm?1 is
assigned to the carbonyl stretching vibration of the acetylated amino group.
After mixing with GO, the band at 1736 cm-1,
1404 cm-1, 1231cm-1, 3428cm-1 which
corresponded to the stretching band of C=O in carboxylic acid moieties, C-OH,
C-O-C, -OH were shifted to 1711 cm-1, 1379 cm-1, 1155cm-1, 3424cm-1 respectively in
the case of CS/GO (Fig.2A), which indicating the formation of hydrogen bonding
and an electrostatic interaction between chitosan and GO. 32. For the Polypyrrole
powders (Fig. S1), FT-IR spectrum showed the main characteristic peaks at 788
cm?1 corresponding to C-N bond, 1311 cm?1 corresponding
to C-H deformation, 1546 cm?1 and 1458 cm?1 corresponding
to the fundamental vibrations of polypyrrole ring, the peak at 1633 cm?1
corresponding to C=C stretching, the peak at 3423 cm?1 corresponds
to the N-H stretching 33, 34. After in-situ polymerization of PY with
CS/GO, the FT-IR spectrum (Fig.2B), of PPC/GO nanocomposite shows the
appearance of peaks at 1462 cm-1, 1550 cm-1, and 3415 cm-1
are related to the C=C, C=N and N=H stretching vibration in the PPY ring,
respectively. The absorption peaks found at 2919 cm-1 and 2844 cm-1
are ascribed to asymmetric stretching and symmetric vibrations of CH2,
respectively. The peak at 1711 cm-1characteristic to C=O in CS/GO
was shifted to 1721 cm-1 in the case of PPC/GO suggesting the ?-?
interaction between the graphene layers and aromatic PPY rings. The appearance
of the peak at 787 cm-1 this may be due to the additional bond
formed between