UCLA

Nanostructured conducting polymers such as polyaniline are promising candidates for next-generation electronics because of their low cost, mechanical flexibility, good solution processability, along with the low-dimensionality that is characteristic of nanoscale materials. Here, we further expand the attractive properties of polyaniline by copolymerizing it with a variety of substituted aniline monomers, with electron donating groups, electron withdrawing groups, or substituents that can enhance the solubility of the final polymer. The resulting copolymers combine the unique properties of the homopolymers such as the high electrical conductivity of polyaniline and the good processability/solubility of the polyaniline derivatives.

Scanning electron microscope (SEM) images reveal the nanofibrous nature of the copolymers with uniform diameters. The feeding ratios of aniline and aniline derivatives of one representative copolymer are elucidated from 1H-NMR studies. The different relative compositions of each copolymer also allow us to tune the electrical transport properties, the optical absorption, and the stability of the aqueous dispersion step-by-step, characterized by 2- probe resistance, UV-vis, and Zeta-potential measurements, respectively.

The resulting copolymers exhibit enhanced conductivity compared to the poorly conductive substituted-polyaniline homopolymers and better aqueous dispersion stability than their conventional bulk counterparts, rendering them suitable for many potential applications.