Novel Fabrication and Characterization Methods for Conducting Polymer Nanostructures and Microstructures

To develop devices based on conducting polymers for the benefit of humanity - such as, for example, artificial muscles and lab-on-a-chip diagnostics - we require the ability to reliably fabricate and understand these materials at the micro and nano scales. In this thesis I present research towards that goal, by developing novel experimental techniques for the fabrication and characterization of poly(3,4-ethylenedioxythiophene) (PEDOT) and polyaniline (PANI), two prominent conducting polymers. Many of the strategies presented herein are based on miniaturized pipettes driven by scanning ion conductance microscopy (SICM), with some complementary techniques also explored. I begin this thesis work by describing the construction of a low-cost SICM, and its further development to include novel modifications that enable its application to conducting polymers. One of these is the first SICM-based measurement of the ion flux that underpins PEDOT actuation, an important issue in artificial muscles and micropumps. Another is the first electrochemical fabrication of microscale PEDOT and PANI structures and arrays. This approach is then extended to map the activity of the resulting microstructures using modified SICM-based protocols. For example, it is demonstrated that pipette-defined cyclic voltammetry can yield highly localized characterization of microstructures, an important topic for biosensor applications. Indeed, this technique is demonstrated herein for the characterization of a PEDOT nanowire based DNA sensor. Finally, complementary studies on PANI nanostructures are also presented. The first synchrotron radiation studies of PANI nanotube self-assembly is undertaken, revealing crystallinity at critical early stages of the reaction. Furthermore, focused ion beam and electron microscopy techniques are used to perform studies on the electrical properties on individual PANI nanostructures. Both of these have relevance for potential integration with the aforementioned SICM-based techniques. Altogether, these methodological innovations and resulting findings represent significant advances in the burgeoning field of pipette-localized conducting polymer fabrication and characterization. I conclude the thesis with implications discussed for future fundamental research and device applications.

Name thesis:degree_name

PhD

Level thesis:degree_level

Doctoral

Grantor dc:publisher

ResearchSpace@Auckland

Year dc:date.issued

2012

Author dc:creator

• Laslau, Cosmin

Advisors dc:contributor.advisor

• Travas-Sejdic, J
• Williams, D

Statement dc:rights

• Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. Previously published items are made available in accordance with the copyright policy of the publisher.

Licence dc:rights.uri

• https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htm

Handle dc:identifier.uri

https://hdl.handle.net/2292/19604

OAI identifier oai:identifier

oai:researchspace.auckland.ac.nz:2292/19604