Optimization of the sequential polymerization synthesis method for polypyrrole films

• We prepared polypyrrole films using a novel electrochemical polymerization method.
• We studied the effect of current density, temperature and solvent washing method.
• Increased film conductivity, mechanical strength and electroactivity were observed.
• The films were used as electromechanical actuators.

Polypyrrole (PPy) is widely used as an electroactive material and is most often synthesized using electrochemical polymerization. Recently, a new electropolymerization method [1] was introduced that involved preparing the PPy as a sequential series of electrodeposited layers with solvent washing in between each deposited layer. This method enabled high quality PPy free-standing films to be prepared in a relatively short time. The purpose of the present study was to investigate the effect of the polymerization current density on the mechanical and electrical properties of the sequentially polymerized (SEP) PPy films. It was found that a low current density (0.1 mA/cm2) and low temperature (−31 °C) produced polypyrrole films of significantly higher conductivity and excellent mechanical properties when compared with films made at higher current densities either using the SEP method or by conventional, continuous electrodeposition.