Eco-friendly enhanced microwave synthesis of polyaniline/chitosan-AgNP composites, their physical characterisation and antibacterial properties

Abstract

An eco-friendly enhanced microwave (MW) method was used to prepare antibacterial polyaniline/chitosan-silver nanoparticle (PANI/Ch-AgNP) composites at room temperature through the chemical in situ polymerisation of aniline using potassium iodate (KIO3) as oxidising agent and different molecular weight chitosans (Chs) in the presence of 10 wt% of AgNP in the starting reaction mixture for the period of 10 min. The comparable analysis of physical, morphological and antibacterial properties PANI/Ch-AgNP samples synthesised by a classical chemical synthesis (CS) and enhanced MW method showed that AgNP influenced the aniline polymerisation in the presence of Ch biopolymer in the PANI-based composite. Enhanced crosslinking of Ch with PANI with some porous nanostructures was observed in MW PANI/Ch-AgNP 1:1 composites. Furthermore, a predominant Ch morphology was noticed in all CS PANI/Ch-AgNP 1:1 samples which indicates that in classical synthesis method the presence of AgNP constraints PANI fibre formation and reduces electrical conductivity in these composites in comparison with the ones prepared by MW method. All PANI/Ch-AgNP 1:1 composites exhibited better bactericidal (bacterial killing) efficacy against both types of bacteria than any of the Chs or PANI control samples. These results suggested that facile, scalable, and low-cost enhanced MW method can be used for tuning PANI formation conditions favouring the particular physical properties of PANI/Ch-AgNP composites.