Novel polyaniline nanostructures based on nano-templating for sensing applications

Principal Researcher: Dr. Ewa Kazimierska

Various Nanostructures of Polyaniline (SEM images)

Recently emerged and very fast growing science of nanotechnology is continuously calling for new types of materials. Increased demand for such new materials and development of techniques that make their properties accessible has attracted our interest to conducting polymer nanostructures. Conducting electroactive polymers combine the electronic properties (magnetic, conducting and optical) of metals with those of conventional organic polymers. They are easily fabricated from their monomers and deposited onto a conductive surface of a given substrate in the form of bulk films by electrochemical or chemical polymerization. Polyaniline (PANI) is one type of intelligent conducting polymer. When synthesized at the nanoscale, PANI possess unique physical and chemical features, which are reflected by improved electronic, chemical, electrochemical, and mechanical properties when compared with its bulk counterpart. However, very little work has been performed investigating the physical properties of such materials or how these properties are dependent on the particle size.

The initial objective of this research is to prepare new, novel, PANI composites and nanoporous structures and films using a nano-templating methodology at length scales approaching 10 nm. Polystyrene (PS) nanoparticles used as templates are deposited to the electrode substrate initially. Depending on the charge of the (PS) nanoparticles, the growth of the polyaniline can be very finely controlled. Positively charged aniline electropolymerizes around negatively charged PS to create core-shell, or even hollow sphere structures of PANI upon removal of the template. Or in the case of positively charged PS nanoparticles, growth can be directed on the electrode substrate which, upon removal of PS, results in nanoporous and honeycomb structures.

The emphasis of my research is to work towards obtaining ever decreasing length scales in these polyaniline composites and nanoporous films, characterizing them in full, and looking to apply them in new types of sensing applications for the biomedical industry.