Nano-engineering of conducting polymers /

Abstract

Oxidative interfacial and template polymerization approaches were developed to synthesize conducting polymer nanostructures for possible applications of these materials in charge storage devices like supercapacitors. Resulting nano-structured materials were characterized using scanning electron microscopy (SEM), fourier transform infrared coupled with attenuated total reflectance (FTIR-ATR), cyclic voltammeter, ultraviolet-visible-near infrared (UV-vis-NIR) spectrophotometer, multimeter and Brunaur-Emmett-Teller (BET) analyses. Two different methods were used to obtain desired nano-structured conducting polymers. In the first method, a homogeneous polypyrrole (PPy) nano-network structure was produced. Optimization results indicated that mole ratios of oxidant to monomer should be kept as 4:1 and surfactant to monomer as 3:1, 4:1 and 5:1 for the production of PPy nanofibers in networks. The average size of fibers and beads were measured as ca. 150 and 300 nm, respectively. The electrical conductivity measurements and electrochemical studies with cyclic voltammetry resulted in reasonable electroactivity of these PPy nano-networks. BET analyses resulted in a surface area greater than 500 m2/g. In the latter method, conductive nano-arrays of polypyrrole (PPy) (1), poly(Nmethylpyrrole) (P(NMPy)) (2), poly(thiophene) (PTh) (3) and poly(3,4- ethylenedioxythiophene) (PEDOT) (4) were aligned in one dimension (1D). Reaction conditions; such as, monomer concentrations, types of membranes and solvents for the synthesis of each polymer nanostructure were optimized. SEM images revealed that fiber diameters were in a range of 80-350 nm with 10-30 ´m length for conducting polymer nanotubules aligned unidirectionally. Characterization of P(NMPy) nanotubules with cyclic voltammetry indicated that template-synthesized materials are electroactive as desired.