Structural, optical, and electrical characterization of chitosan: methylcellulose polymer blends based film

Solid polymer blend system based on chitosan (CH) and methylcellulose (MC) have been prepared through solvent casting technique and characterized by X-ray diffraction (XRD), UV-Visible, and impedance spectroscopy. The XRD data revealed the increase of amorphous domains of polymer blend matrix comparing to that of the pure polymers. The estimated optical band gap energy of CH:MC blends with 75:25 weight ratio showed a minimum value of 5.135 eV, companion with the maximum value of tail of localized state. Electrical conductivity analysis indicates that the blend samples have a larger conductivity compared to that of pure polymer samples. The highest room temperature dc conductivity was achieved for CH:MC blends with 75:25 weight ratio. Thus, the optical and electrical results confirm the same result. Temperature-dependence dc conductivity study follows Arrhenius model. The highest conducting composition has the lowest activation energy (0.46 eV). The frequency dependence of the ac conductivity follows Jonscher's power law and indicates that the correlated barrier hopping is the most apposite mechanism for conduction in the present system. The asymmetric peak of the imaginary part of electric modulus obtained from the dielectric analysis suggests a non-Debye type relaxation.