Professor Richard Kaner
University of California Los Angeles, USA
Ric Kaner received a Ph.D. in Inorganic Chemistry from the University of Pennsylvania with Professor Alan MacDiarmid in 1984 followed by two and a half years of postdoctoral research at UC Berkeley. He joined UCLA in 1987 as an assistant professor, earned tenure in 1991 and became a full professor in 1993. He has received awards from the Dreyfus, Guggenheim, Packard and Sloan Foundations as well as the American Chemical Society for his work on new routes to refractory materials including high-temperature ceramics, intercalation compounds, fulleride superconductors, superhard materials and conducting polymers. His conjugated polymer research focuses on nanofibres of polyaniline and their use in sensors, actuators, molecular memory and flash welding. In 2005 he worked with Prof. Gordon Wallace at the University of Wollongong on a Fulbright sabbatical fellowship. To date he has published over 150 peer reviewed articles, 8 patents (with 7 more pending) and raised over $6 million in grant funds.
Synthesis, Collaborations And Applications Of Conducting Polymer Nanofibres
Richard B. Kaner, Christina Baker, Julio D’Arcy, Robert Kojima and Henry Tran
Department of Chemistry and Biochemistry and California NanoSystems Institute, UCLA, USA
By using either interfacial polymerization or rapidly mixing aniline, oxidant and acid, pure nanofibres of polyaniline can be produced.[1,2,3] The key to forming nanofibres is to suppress secondary growth that results in the agglomerated particles found in conventional polyaniline synthesis.[4] Not shaking or stirring the solutions after the initial reaction is also important.[5] Our methods are template-free and readily scalable. Stable and processable colloids are now available.[6] The synthesis of nanofibres of polyaniline derivatives (including collaborative work on polyaniline/PMAS nanocomposites with IPRI) has recently been accomplished by adding appropriate initiators.[7,8] The applicability of these ideas to form nanostructures
of polypyrrole and polythiophene will be discussed.
Polyaniline nanofibres exhibit an exceptional photothermal effect in which they instantaneously
melt and cross-link upon exposure to a camera flash.[9] This novel flash welding technique
can be used to form patterned nanofibre films, create polymer based nanocomposites and make asymmetric polymer membranes. These asymmetric structures can act as mechanical actuators (artificial muscles) when exposed to strong acids as demonstrated in collaboration with researchers at IPRI.
Polyaniline nanofibres are useful in many applications such as resistive-type sensors where their high surface area enable very rapid response times often less than two seconds.[10,11] Polyaniline
nanofibres can be modified to respond to many different vapors including toxic agents such as hydrogen sulfide. The key is using a metal salt such as CuCl2 which reacts with H2S to produce CuS and HCl. This process convertsa weak acid (H2S) into a strong acid (HCl) that in turn can be readily detected at very low concentrations.
Polyaniline nanofibres can be decorated with metal nanoparticles which not only can enhance sensor response but also leads to molecular memory devices.[12]
References
[1] Huang, J.; Virji, S.; Weiller, B.H.; Kaner, R.B. J. Am. Chem. Soc. 2003, 125, 314.
[2] Huang, J.; Kaner, R.B. J. Am. Chem. Soc. 2004, 126, 851.
[3] Huang, J.; Kaner R.B. Angew. Chem. Inter. Edition
2004, 43, 5817.
[4] Huang, J.; Kaner, R.B. Chem. Commun. 2006. 367.
[5] Li, D.; Kaner, R.B. J. Am. Chem. Soc. 2006, 128, 968.
[6] Li, D.; Kaner, R.B. Chem. Commun. 2005. 3286.
[7] Tran, H.; Kaner, R.B. Chem. Commun. 2006, in press.
[8] Masdarolomoor, F.; Innis, P.C.; Ashraf, S.; Kaner,
R.B.; Wallace, G.G.; Macromol. Rapid Commun. (in press).
[9] Huang, J.; Kaner, R.B. Nature Mater. 2004, 3, 783.
[10] Virji, S.; Fowler, J.D.; Baker, C.O.; Huang, J.; Kaner, R.B.; Weiller, B.H.; Small 2005, 1, 624.
[11] Virji, S.; Huang, J.; Kaner, R.B.; Weiller, B.H.; Nano Lett. 2004, 4, 491.
kaner@chem.ucla.edu
aholmes@unimelb.edu.au