Evaluation of conductivity of nanostructured polyaniline/cellulose nanocrystals (PANI/CNC) obtained via in situ polymerization

Abstract Cellulose nanocrystals (CNC) have a wide range of applications due to the high aspect ratio, crystallinity and mechanical properties in addition to being renewable and biodegradable. Polyaniline (PANI) is a conductive polymer that has attracted extensive attention due to low density and high electrical conductivity. However, polyaniline in the bulk form has some limitations in terms of use because of its chemical nature as a consequence of secondary hydrogen bonds that reduces conformability and mechanical strength. Aiming at the applicability of polyaniline as films or gels, this work combines two types of materials: cellulose nanocrystals (CNC) and polyaniline through an in situ polymerization of PANI in CNC suspensions to create a nanostructured material. Thermal stability (TGA), particle size (Zeta-sizer), physical and chemical characteristics (FTIR, UV-vis), the process of polymerization (Voc) as well as conductivity was evaluated according to the different PANI/CNC ratios (R = 0.05, 0.1, 0.2, 0.3 and 0.4). Results show that particle size, thermal stability and time of polymerization increase with CNC concentration, indicating that cellulose nanostructure works as a backbone to PANI deposition. FTIR and UV-vis show the evolution of the main characteristics absorption bands around 1220 cm−1 , 1487 cm−1 and 1594 cm−1 (IR) and 381∼391 nm, respectively while the PANI/CNC ratios increase. Otherwise, conductivity values of the nanostructured PANI/CNC with the higher content of PANI is 8.9 × 10−1 S/cm−1 compared to 3.63 S/cm−1 to neat polyaniline, showing to be a great alternative of nanostructured material.