Ian Wark Research Institute
ARC Special Research Centre
ARC Special Research Centre
Research Area: Chemistry, biochemistry, biotechnology and sensors
Degree: Honours
Supervisor: A/Prof Rossen Sedev
Description: Gold, platinum and quartz surfaces, as examples, can be chemically modified with self-assembling pyrimidine molecules, attached to long alkyl chains terminated by an appropriate functional group as thiol. When irradiated with light of specific wavelengths these surfaces undergo substantial reversible wetting changes over a number of cycles. Neither the liquid phase nor the solid phase needs to be altered in order to bring about a large change in contact angle. The pyrimidine molecules that we have utilized are C-5 modified uracils that are able to dimerise when irradiated with light of a specific wavelength. The wetting behaviour is brought about by changes in the surface charge and/or conformational changes that are highly dependent on the functionality of the pyrimidine groups. Surfaces patterned with monolayers incorporating these responsive molecules exhibit different wetting properties depending upon the wavelength of light the surface is exposed to. Functionality or the molecular structure of the surface coating and wettability are strongly linked.
The use of sensitisers to cause photosplitting of the dimer will be actively explored, along with molecules that respond to magnetic forces. We wish to exploit this behaviour and learn more about how to design molecules and surfaces for specific purposes. This may include directed liquid movement on surfaces, surface encapsulation processes for drug delivery etc. Applications such as molecular recognition, biosensors, optical imaging and computer data storage beckon. Active cooperation with national laboratories, as well as with international partners in Asia and Europe, will take place. The project could lead on to doctoral studies.
References
1. S Abbott, J Ralston, GD Reynolds and RA Hayes, 'Reversible Wettability of Photoresponsive Pyrimidine Coated Surfaces', Langmuir, 15, No. 26, 8923-8928, (1999).
2. N Richards, A Quinn, J Ralston, G Reynolds and R Sedev, 'Light and Electric Potential Induced Reversible Wetting on Structured Surfaces', Functional Fillers and Nanoscale Materials, Edited by J Kellar, M. Herpfer and B. Moudgil, SME, 41-57, 2003.
