Synthesis, Properties and Applications of Conducting Polymer Nano- Objects

Abstract

Two different approaches are used to produce conducting polymer nano-objects. One is a “top-down” approach which involves laser ablation of conducting polymer films using laser light interference patterns (direct laser interference patterning, DLIP) to produce various surface shapes, including nanowires and nanodots. Polyaniline(PANI) and polypyrrole (PPy) nanostructures could be easily produced by ablation of films, previously formed by in-situ polymerization of the aromatic monomers. The other is a “bottom-up” approach involving the controlled nucleation and growth during monomer polymerization. This is achieved by performing the polymerization at the interface of two immiscible solvents. Both kinds of nanomaterials are characterized using dynamic light scattering, TEM, EDAX, FTIR, UV-vis and fluorescence spectroscopy. The structures are studied by SEM-FIB, optical and fluorescence microscopy along with water contact angle. It is shown that nanometric sized structures can be made by both methods. The chemical structures are quite similar or identical to that of the bulk polymer. While PANI nanofibers are dispersed in acid media, due to the surface charge related with chain protonation, they agglomerate in neutral media. In the interest of biological applications, different soluble polymers are used to help disperse the nanofibers at neutral pH. Both the dispersing agent and PANI nanofibers have to be innocuous to biological cells and higher organisms, like frog larvae. The successful intake of PANI nanofibers into cancer line cells and frog larvae prompts its application as NIR radiation absorbers in photothermal or photoacoustic tumor therapy and/or tomography.