Synthesis of Blend Polymer (PVA / PANI)/Copper (1) Oxide Nanocomposite: Thermal Analysis and UV-Vis Spectra Specifications

Abstract

Copper (1) oxide nanoparticles together with matrix polymers of polyvinyl alcohol (PVA) and polyaniline (PANI) composite films were synthesized, as these materials are of importance in optoelectronic applications. ‎Nanoparticles of Cu₂O were produced by chemical precipitation. Polymerization of aniline was carried out through polymerization in an acidic medium. Structural, thermal, and optical properties of PVA+PANI/Cu₂O nanocomposite were inspected by x-ray diffraction (XRD), scanning electron microscopy (SEM), fourier-transform infrared (FTIR), differential scanning calorimeter (DSC) and ultraviolet-visible spectroscopy (UV-Vis spectroscopy). X-ray diffraction peaks at 29.53°, 36.34°, and 42.22° indicated the presence of cuprous oxide nanoparticles, having high dispersions and limited size distributions. The estimated average size of Cu₂O nanoparticles was ~ 17.1525 nm. A characteristic peak at around 2θ = 18.5° was attributed to periodical parallel and perpendicular polymer chains, which denoted the formation of PANI. SEM results indicated the symmetrical dispersion of Cu₂O nanoparticles inside the hybrid polymer of PVA and PANI matrix, being potentially useful for encapsulation and acting as a good capping agent. FTIR results established the formation of PANI and Cu₂O with nanocrystalline nature. DSC results revealed the appearance of one single peak of T_g which decreased with Cu₂O content of 4% wt, followed by an increase of that value by increasing Cu₂O content up to 16%wt. Thermogram analysis of the PANI and PVA embedded with Cu₂O form showed an exothermic peak at (240-292)℃ affiliated to the cross-linking reaction, while the T_m value of prepared nanocomposites is just about close to that of PVA polymer. The results indicated that there is an increase in thermal stability due to the presence of Cu₂O NPS within the matrix of polymers. The distinguishing peaks at 330, 347, and 457 nm which refer to PANI are assigned to π−π* electron transitions among the benzenoid rings. The high absorption intensity of the peak at 470 nm for the blended PVA+PANI  having 12% wt of  Cu₂O NPS is assigned due to the inter-band transitions for electrons of the core copper as well as copper oxide. This points out that the increasing quantity of Cu₂O NPs leads to increases in the amounts of highly oxidized structures in PANI and decreases in the doping electrons and length of conjugation throughout the incorporation of Cu₂O NPs into PANI matrix. Depending on the practical results, it can be said that these polymeric nanocomposites can be efficiently used in photovoltaic technology applications.