Study the characterization and thermoelectrical properties of the polyvinyl alcohol / Polyaniline polymer blend thick films

This study investigated the impact of the introduction of Polyaniline (PANi) on the structural, thermal stability, electrical, and thermoelectric properties of polyvinyl alcohol (PVA)_1-x Polyaniline (PANi)_x blend composites, (where x = 0, 10, 20, and 30 wt.%). The prepared blends were synthesized via the casting technique. The process of polymerizing polyaniline (PANi) was executed in a methodical and ordered manner. The obtained films from these blends are analyzed to assess their surface characteristics and structural morphology through elemental analysis, scanning electron microscopy (SEM), and Fourier-transform infrared spectroscopy (FTIR), as well as their thermal properties via thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The PVA hydrogen bonding facilitates the uniform dispersion of PANi among the chains of PVA, which increases the amorphous structure of the prepared films. The surface of the pure PVA film is characterized by a smooth surface. However, a mixture of nanofibers with slightly white porous spongy morphology patches appeared in the PANi-doped films. Furthermore, the incorporation of PANi into the PVA matrix improves the thermal stability of the prepared films. The impact of PANi on the electrical properties, Seebeck Coefficient, and thermal conductivity of the prepared composites is evaluated using the four-probe direct technique and laser flash measurements. SEM images reveal a heterogeneous distribution of conductive PANi particles within the continuous PVA matrix. A notable aspect of this investigation is the significant increment in the DC electrical conductivity of the blend films at room temperature, which increases from 2.08 × 10^^-12 S/m for the pure PVA film to 0.08 S/m for the film containing 30 wt.% PANi. The Seebeck Coefficient decreases with loading the PANi due to the increase in the charge carrier concentration. Concurrently, there was a slight enhancement in thermal conductivity, increasing from 0.1304 W m^-1 K^-1 to 0.362 W m⁻¹ K^-1 for the 0 wt.% and 30 wt.% films, respectively. The findings suggest a polymer blend with significant potential for thermoelectrical applications, exhibiting high electrical and low thermal conductivity, which is advantageous for thermoelectric applications.