Thermal, dielectric and optical studies on cellulose acetate butyrate-gold nanocomposite films prepared by laser ablation

This work employed pulsed laser ablation to produce cellulose acetate butyrate-gold (CAB-Au) nanocomposite films and the evaluation of their structural and thermal characteristics using Raman, X-ray diffraction (XRD), thermogravimetric analysis (TGA), and Differential Scanning Calorimetry (DSC). In the frequency range 0.1-10 MHz, nanocomposite films' dielectric constant, loss, and electric modulus behavior were investigated as a function of temperature. The refractive index, finesse coefficient, Brewster coefficient, critical angles, dielectric function, and color properties of nano -composite films were examined in the wavelength range 190-800 nm. X-ray diffraction shows a strong Au diffraction signal in all samples, confirming Au NPs. The SEM micrograph shows Au embedded in CAB. The CAB-Au nanocomposites had higher thermal stabilities (Tm) than pure CAB, and the DSC thermograms showed a fluctuating glass transition temperature due to the dynamics of organic-inorganic interactions in the nanocomposite films. Dielectric dispersion is caused by hidden dipolar polarization. The CAB (5 min) sample had the highest ac conductivity as a function of frequency at various temperatures as the Au content in the Au/CAB composite rose. The simplest quantum mechanical tunneling (QMT) model also best explains the ac conduction property. We found a relationship between the nanocomposites' refractive index and the amount (extent of incorporation) of Au in the materials, with laser irradiation time determining the various color constants. Tauc plots reveal a permitted transition with an optical energy gap of 5.1eV for the polymer film and 4.75eV after 10 and 20 min of laser irradiation.(c) 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).