Polypyrrole–ZnO nanohybrids: effect of CSA doping on structure, morphology and optoelectronic properties
Appl Nanosci
Polypyrrole-ZnO nanohybrids: effect of CSA doping on structure, morphology and optoelectronic properties
M. A. Chougule 0 1
G. D. Khuspe 0 1
Shashwati Sen 0 1
V. B. Patil 0 1
0 S. Sen Crystal Technology Section, Technical Physics Division , BARC, Mumbai , India
1 M. A. Chougule G. D. Khuspe V. B. Patil (&) Materials Research Laboratory, School of Physical Sciences, Solapur University , Solapur 413255, MS , India
Polypyrrole-ZnO (PPy-ZnO) nanohybrid was prepared from PPy and ZnO nanoparticles (NPs). Nanohybrids of PPy-ZnO were doped with camphor sulfonic acid (CSA) with different weight ratios (10-50 %). The CSA-doped nanohybrids obtained were characterized by X-ray diffraction, FTIR, field emission SEM, UV-vis spectroscopy and electrical transport method. Structural investigations using X-ray diffraction shows new peaks appeared at 15.44 and 17.61 in the XRD pattern of CSAdoped PPy-ZnO nanohybrids belong to CSA. The FTIR spectra confirmed the strong interaction between the CSA and PPy-ZnO nanohybrids. The UV-visible spectrums revealed the enhancement of doping level for the 30 % CSA-doped PPy-ZnO nanohybrid film which is assigned to the existence of greater number of charges on the polymer backbone. The room temperature dc electrical conductivity of CSA-doped PPy-ZnO nanohybrids were observed to depend on the CSA doping and the morphology.
PPy-ZnO nanohybrid; Structural properties; Optical properties; Electrical properties
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In recent years, intrinsic conducting polymers with
conjugated double bonds have been attracted much attention as
advanced materials. Among those conducting polymers,
polypyrrole (PPy) is especially promising for commercial
applications because of its good environmental stability,
facile synthesis, and higher conductivity than many other
conducting polymers. PPy can often be used as biosensors
(Vidal et al. 1999; Campbell et al. 1999), gas sensors
(Kincal et al. 1998; Kemp et al. 1999), wires (Jerome
et al. 1999), microactuators (Smela 1999), antielectrostatic
coatings (Ouyang and Li 1997), solid electrolytic capacitor
(Arora et al. 2006; Ouyang and Li 1997), electrochromic
windows and displays, and packaging, polymeric batteries,
electronic devices and functional membranes, etc.
(Skotheim 1986; Skotheim et al. 1998; Wallace et al. 1997). PPy
coatings have an excellent thermal stability and are good
candidate for use in carbon composites (Iroh and Williams
1999). Furthermore, the electrochemical process
parameters affecting the properties of the PPy coatings are also
investigated (Su and Iroh 1998). PPy can be easily prepared
by either an oxidatively chemical or electrochemical
polymerization of pyrrole. However, synthetically
conductive PPy is insoluble and infusible, which restricts it is
processing and applications in other fields.
Shen and Wan (1998) studied the solubility in m-cresol,
room temperature conductivity, morphology and thermal
stability of PPy synthesized by in situ doping
polymerization in the present of sulfonic acid. It was noted that good
solvating ability of sulfonic acid, such as DBSA and BNSA
(5-butylnaphthalene), renders PPy soluble, while sulfonic
acids only having large molecular size, such as CSA
(camphor sulfonic acid) and MBSA (p-methylbenzenes
sulfonic acid or p-toluene sulfonic acid), fail to make PPy
soluble. The nature of sulfonic acid also has an influence
on morphology of the resulting PPy. The images of PPy
doped with CSA, DBSA and MBSA have typical granular
morphology, but PPy doped with NSA (b-naphthalene) is
fibrillar. And it was also observed that PPy doped with NSA
and BNSA are thermostable based on the measurement of
weight loss. However, it has been found that doping PPy
with mixed acid containing CSA and DBSA could get
soluble conductive PPy with room temperature conductivity
(2–18 S/cm) (Shen and Wan 1998). Pressure effects on the
electrical conductivity of doped PPy have been studied
(Fedorko 1998). The pressure dependence has
characteristics of a phase transition and is interpreted as a
conformational wit-rod transition. The pressure effect should be
considered in experiments with PPy gas sensors. The
pressure and temperature dependences the electric
condition of thin films composed of doped PPy microtubules are
also measured (Mikat et al. 1999). In addition, it was found
that the conductivity of PPy electrochemically polymerized
in acrylamide solution is lower that of PPy prepared in the
absence of acrylamide (Sarac et al. 1998). The difference is
attributed to the insulating effect of acrylamide. Besides
above, synthesis of nanostructures composed of PPy can
enhance in electronic conductivity compared to analog
polymer bulk conductivity (Duchet et al. 1998).
The syntheses of PPy–ZnO nanoparticles with different
combinations of the two materials have attracted more and
more attention, since they have interesting physical
properties and potential applications. These particles not only
combine the advantageous properties (...truncated)