Water–Chloroform Interface Assisted Microstructure Tuning of Polypyrrole–Silver Sheets

The liquid–liquid interface of two immiscible solvents remarkably controls the morphology of polymeric nanostructures as compared to the polymerization in single solvent systems. The polymerization of pyrrole in the water–chloroform medium using silver nitrate (AgNO3) as oxidant yields polypyrrole/silver (PPy/Ag) sheets. The water–chloroform interface acts as a template for the growth of PPy/Ag hybrids into sheets by preventing the secondary growth of silver associated pyrrole oligomers in a three-dimensional (3-D) manner. On the contrary, the 3-D growth of pyrrole oligomers into spherical shapes at the water–chloroform interface is observed when ammonium persulfate (APS) is used as the oxidant. Transmission electron microscopic and scanning electron microscopic images reveal the sheetlike morphology of PPy/Ag with a relatively uniform distribution of Ag NPs (∼100 nm) on PPy sheets. The ratio of aqueous–organic bisolvent and the concentration/type of oxidant have a distinct effect on morphology, crystallinity, and electrical properties of PPy/Ag sheets. The dispersed PPy/Ag sheets are stable in moderately polar solvents up to 2 weeks. The electrochemical behavior of PPy/Ag sheets is confirmed by H2O2 sensing capability through cyclic voltammetry experiments. The antibacterial activity toward E. coli and S. aureus is quantitatively assessed using the minimum bactericidal concentration (MBC) determination.