Microstructural and optical properties of polyvinyl alcohol/manganese chloride composite film

Films of pure polyvinyl alcohol (PVA) and its manganese chloride filled polymer composite film (MPVA) were prepared and their optical properties were evaluated. XRD, UV-vis, and FTIR analyses reveal that there is strong interaction between polyvinyl alcohol and manganese chloride. Interchain separation (R) for pristine PVA and MPVA composite films was found as 5.60 and 4.69 , respectively, thus showing polymer chains are more compact in MPVA. Optical band gap of polyvinyl alcohol was reduced on incorporation of manganese chloride in polyvinyl alcohol to cause approximately 2.5-fold increase in optical conductivity. Refractive index of MPVA was found to be higher than that of PVA in the visible range up to 710 nm but beyond that it became lower than that of PVA. Abbe Number was decreased on incorporation of manganese chloride to PVA with concomitant increase in dispersion energy. Urbach energy (E-u) for PVA and MPVA was found to be 0.70 and 0.82 eV, respectively. AFM study reveals formation of sunflower like assembled texture at nano-scale level in MPVA film and it exhibits a higher root mean square (RMS) roughness and absorbance than those of pristine PVA film. Average oscillation wavelength ((0)) was found to be close to the respective absorption edge; and MPVA showed higher oscillation strength (S-0) than that of PVA. POLYM. COMPOS., 40:E765-E775, 2019. (c) 2018 Society of Plastics Engineers