Copper alumina reinforced poly(aniline-co-indole) nanocomposites for optoelectronic devices

Abstract

Copper alumina (Cu-Al2O3) reinforced poly(aniline- co-indole) (PANI- co-PIN) nanocomposites were prepared and characterised by UV-vis spectroscopy, FE-SEM and DSC. The bandgap energy decreased with the addition of Cu-Al2O3 to PANI- co-PIN. The FE-SEM confirms the uniform dispersion of nanoparticles in the copolymer. The DSC showed a shift in glass transition temperatures to higher regions with Cu-Al2O3 concentrations. The frequency-temperature-dependent dielectric parameters and electrical conductivity of nanocomposites were investigated. Activation energy calculated from Arrhenius equation decreases with increasing frequency. The real and imaginary part of electric modulus implies the thermally activated dielectric relaxations. The decreasing radius of semicircles in Nyquist plot with increasing temperatures indicates the existence of thermally activated conduction mechanisms. Different theoretical models were used to predict the DC conductivity mechanism in copolymer nanocomposites.

High performance biopolymer blend nanocomposites derived from cashew gum/polyvinyl alcohol/boehmite for flexible electronic devices

“…A long tail end that tends toward zero is found at low frequencies and a rapid rise in toward higher frequency is observed for pure blend and nanocomposites. This confirms the effect of electrode polarization at low frequencies and elimination of electrode polarization at higher frequencies 39 . Interestingly, the plot of with frequency possesses a low frequency tail end with zero and it increases with frequency and reaches a maximum then decreases.…”

“…At low frequencies, the dipoles have enough time to orient with the applied field, but as the frequency increases, the dipoles will not have time to align with the field before it changes its direction. The dielectric constant is higher for boehmite embedded PVA/CG than the virgin blend and this is obviously due to the additional contribution from space charge polarization that exists between the polymer blend matrix and boehmite 39 . The highest dielectric constant is observed for PVA/CG/7 wt% boehmite at 100 Hz, which is 4.2 times more when compared to a virgin PVA/CG blend.…”

“…A better and more homogeneous dispersion of nanoboehmite in the polymer blend matrix at 7 wt% filler loading, makes it the highest conducting among the prepared nanocomposite films. The conducting network is disturbed by the formation of agglomerates at higher nanofiller content and thus the free charge carriers are reduced 39 . This probably leads to decreased conductivity beyond 7 wt% loading.…”

“…The dielectric constant is higher for boehmite embedded PVA/CG than the virgin blend and this is obviously due to the additional contribution from space charge polarization that exists between the polymer blend matrix and boehmite. 39 The highest dielectric constant is observed for PVA/CG/7 wt% boehmite at 100 Hz, which is 4.2 times more when compared to a virgin PVA/CG blend. This could be due to the better dispersion and interfacial interaction boehmite at this particular loading which will improve the parallel dipolar ordering of polar groups in the polymer system.…”

“…The conducting network is disturbed by the formation of agglomerates at higher nanofiller content and thus the free charge carriers are reduced. 39 This probably leads to decreased conductivity beyond 7 wt% loading. The graph shows a low and high frequency dispersion region along with a frequency independent plateau in the mid frequency range.…”