Abstract
Polymer nanocomposites (PNCs) films of polyvinyl pyrrolidone (PVP) and carboxymethyl cellulose (CMC) filled with multiwalled carbon nanotubes and silver nanoparticles (MWCNTs/Ag NPs) were prepared by the solution casting method. The XRD spectra depicted the semi-crystalline structure of the resulting films, and the degree of crystallinity (Xc%) value reduced from 27.34% for blend to 19.15% for PNCs formed by filling PVP/CMC with MWCNTs and 1 wt.% of Ag NPs. The FTIR absorption spectra display a shift in peak positions and intensity variations when MWCNTs/Ag NPs concentrations increase. The TEM indicated the spherical morphology of Ag NPs with an average size range of 5–43 nm and the multi-walled structure of MWCNTs with an inner diameter range of 4–45 nm. UV–Vis–NIR spectroscopy indicated that the hybrid nanofiller improved the optical absorbance and refractive index of the host matrix. The SPR peak of Ag NPs was determined, and the optical band gap was calculated using two different approaches. The addition of 0.5 wt.% MWCNTs/1 wt.% Ag NPs narrowed the allowed direct optical bandgap of the blend from 5.16 to 3.04 eV. Using the frequency dependent electrical conductivity and electric modulus, the dynamic ion activity and the type of relaxation process of the PNCs films were investigated. The spectra of the dielectric constant (ε′), and dielectric loss (ε′′) were also obtained at different filling levels, where the ε′ value of these PNCs samples increased by about 10.65 times at a frequency of 10 Hz due to the dominant contribution of interfacial polarization at the interfaces of several conductivity ingredients within the PNCs over the frequency range 0.1 Hz to 10 Hz. The value of DC conductivity (σdc) of PVP/CMC/MWCNTs/1 wt.% Ag NPs sample reached 1.74 × 10–8 S/cm, raising by nearly two orders of magnitude due to the increase of charge carriers and formation of three-dimensional pathways which assist the charges to hop from clusters to neighbors within the PVA/CMC matrix. The obtained experimental results confirm that these PNCs films are candidates for antireflection coatings, integral thin film capacitors, energy storage and flexible nanodielectric for frequency operating conventional/microelectronic devices.