Synthesis and characterisation of nanocellulose-based polyaniline conducting films

In this paper, a relatively new concept of using nanocellulose as matrix material in a composite system has been explored. The functionality of the composite has been enhanced by using polyaniline (PANI) as a functional component. These tunable electrically conducting biocomposites have potential applications in anti-static, electromagnetic interference shielding, sensors, electrodes, and storage devices. Nanocellulose was extracted by hydrolysing bleached flax yarn with sulphuric acid (60 wt.%) at 55 °C for 1 h under vigorous stirring. Thin composite films of nanocellulose with PANI inclusions at different loadings were manufactured using in situ polymerisation where aniline-HCl was polymerised with ammonium peroxydisulfate (APS) as oxidant in aqueous nanocellulose suspension. Thin composite films showed improved combination of flexibility and conductivity. These films could be bent by 180° without breaking. The dependence of electrical conductivity on the concentration of polyaniline (0, 10, 20, 30 wt.%), was investigated. It was found that the conductivity of a film increased significantly with the increase in PANI content from 10% to 30%. The conductivity of the nanocomposite containing 30 wt.% reached 1.9 × 10−2 S/cm, which shows promise in the application of paper-based sensors, flexible electrode and conducting adhesives. The composite film showed improved thermal stability above 300 °C by 15% less weight loss at 500 °C compared to pure nanocellulose films. The morphologies, microstructures, thermal stability properties of the nanocomposite films were also investigated.