Background: Nanocomposites consisting of spatially confined polymeric chains are of
great interest due to their application in optoelectronic and photonics devices. Polymer layered silicate
nanocomposites have attracted much attention in industry as well as academia owing to their remarkable
physical and chemical properties as compared to conventional polymer nanocomposites.
Methods: In present study, comparative investigation of the in-situ polymerization of poly(ophenylenediamine)
intercalated montmorillonite has been done via two methods i.e using poly(o-phenylenediamine) as
filler for MMT in one case and as matrix in the other. Intercalation and in-situ polymerization was confirmed by FT-IR,
UV-Visible spectroscopy and XRD studies. TEM and optical microscopy studies confirmed the self-assembled morphology
of nanocomposites while the fluorescence properties revealed that controlled emission could be achieved by confining
poly(o-phenylenediamine) in MMT galleries.
Result: Intercalation and in-situ polymerization of o-phenylenediamine within MMT was successfully carried out using
sonochemical technique. The growth of conducting polymers in the interlayer region of the clays has been shown to dramatically
improve the properties of conducting polymers. Also, the loading of the polymer in the MMT has shown to influence
the optical properties of the nanocomposite. IR spectra and XRD analysis confirmed the intercalation of POPD
and its polymerization within the clay galleries. UV spectra revealed the doped state of POPD within clay galleries. Highest
oscillator strength of 0.0137 was observed for POPD:MMT-1:0.25. Spherical self-assembled morphology was attained
for POPD:MMT-1:0.25. XRD revealed major shift of 82.5 Å for the nanocomposite POPD:MMT-1:1, POPD:MMT-1:0.5
and MMT:POPD-1:0.25. Blue shift of 20 nm was noticed in the fluorescence spectra of POPD:MMT-1:0.25 and
POPD:MMT-1:0.5 which was correlated to the intense interaction between NH of POPD with SiO of MMT. Highest
quantum yield of 0.345 was achieved in case of POPD:MMT-1:0.25. The gallery confinement was found to control the
optical as well as morphological characteristics of the nanocomposite. The controlled growth of POPD chains and their
minimum aggregation resulted in the formation of self-assembled morphology. Thus, by choosing the optimum filler loading
and by controlling its interaction with the matrix, nanocomposites with controlled architecture can be designed.
Conclusion: It can be concluded that intercalation and exfoliation of nanocomposites largely depends on the experimental
conditions such as type of conducting monomer, clay and organic modifier etc. The preparation technique and processing
conditions influence the overall properties of the nanocomposites. Thus, by choosing the optimum filler loading and by
controlling its interaction with the matrix, nanocomposites with controlled architecture can be designed. Few relevant patents
to the topic have been reviewed and cited.