From Nano Scale Silver Particles to Metallic Bulk Sizes: Increase of Silver Ion Reduction Rate in Chitosan:AgNO₃ Polymer electrolyte Mediated by Titanium Dioxide Filler

Synthesis of silver ion conducting polymer composites and its optical, electrical and morphological properties were conducted. In the study various amounts of titanium dioxide (TiO₂) was added to the chitosan:silver nitrate (CS:AgNt) system. The appearance of SPR peak for CS:AgNt system and CS:AgNt doped with 1 wt.% TiO₂ and disappearance of SPR peak for the system incorporated with 5 wt.% TiO₂ reveals the formation of silver particle from nano scales to bulk metallic sizes. The optical microscope images reveal the formation of silver particles with bulk metallic sizes at wt.% TiO₂ filler . The SEM images show silver particles with small sizes for CS:AgNt and CS:AgNt incorporated with 1 wt.% TiO₂. To make sure the reduction process of silver ions to metallic silver particles the impedance spectroscopy has been carried out. The decrease of dielectric constant and DC conductivity at high TiO₂ concentration was correlated with the results of UV-vis and morphological achievments. Shifting of tanδ loss peak towards the lower frequency side at 5 wt.% TiO₂ is an evident for the decrease in conductivity. The results of the present work reveals that silver ion conducting polymer electrolytes mediated by TiO₂ filler are not suitable for electrochemical device application. Distinct peaks become visible in Mi spectra whereas no peaks can be seen in dielectric loss spectra.