Fine-tuning of conductive and dielectric properties of polypyrrole/TiO₂ nanocomposite-coated polyamide fabric

Structural, conductive and dielectric properties of hybrid Polypyrrole (PPy)-TiO2 nanocomposite-coated polyamide fabric (PA-PPy/TiO2) synthesized by in-situ oxidative polymerization of pyrrole on the surface of polyamide in the presence of colloidal TiO2 NPs (d ~ 4.5 nm) have been studied. Raman spectra confirmed salt form of PPy in both neat PPy and PPy/TiO2-coated PA fabric and indicated its complete coverage. SEM/EDX analysis confirmed presence of TiO2 NPs and changes in granular structure of PPy deposited on the surface of PA fiber depending on the amount of TiO2 NPs. The PA-PPy/TiO2 nanocomposite sample with lowest content of TiO2 NPs (6.79 At.% Ti) showed highest conductivity (~10−6 S/cm) and dissipation factor (tan δ) in the entire frequency range. The lowest amount of TiO2 NPs in the PA-PPy/TiO2 nanocomposite induced two to four orders of magnitude higher tan δ value, compared to neat PPy covered PA fabric, depending on the frequency range. Frequency dependence of real (ϵ′) and imaginary part (ϵ″) of the complex permittivity for neat PA and PPy/TiO2-coated PA fabrics follow the trend of changes in dissipation factor for the same TiO2 NPs concentrations. The presence of TiO2 NPs could be exploited for tuning the conductive and dielectric properties of a conductive layer.