Impact of natural melanin doping on the structural, optical and dielectric characteristics of the PVP/CMC blend. Issue 1 (31st December 2023)

• Record Type: Journal Article
• Authors: El-naggar, A. M.; Heiba, Zein K.; Kamal, A. M.; Alzahrani, Khalid E.; Abd-Elkader, Omar H.; Mohamed, Mohamed Bakr
• Is Part Of: Journal of Taibah University for science. Volume 17:Issue 1(2023)
• Publication Date: 2023-12-31
• Subjects: PVP/CMC -- Melanin -- optical -- dielectric; Science -- Periodicals; Science; Periodicals; 505
• DOI: 10.1080/16583655.2023.2190731
• Languages: English
• ISSNs: 1658-3655

Abstract

Abstract : Undoped and doped polyvinyl pyrrolidone/ carboxymethyl cellulose (PVP/CMC: 50/50%) blended polymers with melanin were formed. X-ray diffraction analysis confirmed the amorphous nature of all blends. Scanning electron microscopy results confirmed the smooth and homogeneous surface of the undoped and doped PVP/CMC blend with melanin. The optical parameters and fluorescence spectra of the PVP/CMC blend were investigated as functions of melanin content. The direct optical band gap ( Eg ) for the used melanin is 2.86 eV. The direct and indirect Eg values for the PVP/CMC blend are 5.1 and (4.9, 3.2) eV, respectively. The direct and indirect Eg values were reduced to (4.5, 3.23) and (2.2, 1.33) eV as the amount of melanin became 3 wt % in the doped blend. The effect of melanin doping on the dielectric constant, dielectric loss, AC conductivity, complex impedance, Nyquist plot of the complex impedance, and electric modulus of the PVP/CMC blend was also studied.