Structure and effects of gold nanoparticles in bacterial cellulose–polyaniline conductive membranes
Bacterial cellulose (BC) and poly(aniline) (PANI) composites were successfully synthesized by in situ polymerization of aniline by ammonium persulphate (APS) in the presence and absence of gold nanoparticles. The composites were fully characterized by different techniques such as SEM and AFM (morphology), Raman and FTIR spectroscopy (chemical structure), EFM (electrical conductivity), thermogravimetric analysis (thermal stability), cyclic voltammetry (charge diffusion) and UV-vis (optical properties). The surface roughness is higher in composites and the polymers interact with each other by strong hydrogen bonds, providing high thermal stability in the BC/PANI composite. The phenazine structure was not present in this composite during synthesis; nevertheless, the local conductivity increased even further in the presence of AuNPs, inducing the interchain redox reactions leading the phenazine structures after electrochemical cycling. The electrical conductivity of composites is highly influenced by the APS in the polymerization step, as observed by EFM. Also, the presence of AuNPs leads to easier diffusional processes through the solid material, as observed by more defined voltammetric waves.