Our group leads the world in research in electroacoustics, a unique new technique which was invented in the School of Chemistry to measure concentrated colloidal suspensions. Electroacoustics involves the generation of ultrasound from the electrical double layer of the colloidal particle. The technology enables measurements of the size and charge of colloidal particles that have never been possible before, which lead to new observations and new control over colloidal processes. There are many fundamental and applied projects that exploit this technique.
Water at hydrophobic interfaces
Our electroacoustic measurement of the surface charge density on oil droplets in water in 2004 led to our theoretical explanation in 2009 why air bubbles, oil drops and even Teflon surfaces all become negatively charged in water by the preferential adsorption of hydroxide ions. More experiments are required to test this new theory of the hydrophobic effect.
On-water' catalysis (with Dr. Chris McErlean)
The presence of hydroxide ions at the oil-water interface paradoxically explains why acid-catalysed organic reactions proceed faster when conducted in aqueous emulsions. Further tests of our mechanism proposed in 2010 were conducted and provided additional evidence in support of the acid-catalysis explanation, contrary to the prevailing hydrogen bonding model. Collaboration with Professor Leo Radom and Dr Bun Chan led to further, theoretical support for the acid catalysis.
The adsorption of hydroxide ions at the oil-water interface means that, as water drops in oil become smaller, the interior of the drops become acidic. Microfluidic techniques can be used to observe this effect and then to exploit it by using the drops as microreactors for synthesis.
- Beattie, JK and Djerdjev, AM. The pristine oil/water interface: Surfactant-free hydroxide-charged emulsions. Angewandte Chemie International English Edition, 43 (27), 3568-71, 2004. DOI: 10.1002/anie.200453916
- Gray-Weale, A and Beattie, JK. An explanation for the charge on water’s surface. Phys. Chem. Chem. Phys., 11 (46), 10994-11005, 2009. DOI: 10.1039/b901806a
- Beattie, JK and Djerdjev, AM and Warr, GG. The surface of neat water is basic. Faraday Discussions, 141 (1), 31-39, 2009. DOI: 10.1039/b805266b
- Beattie, JK; McErlean, CSP and Phippen, CBW. The mechanism of on-water catalysis. Chemistry: A European Journal, 16 (30), 8972-8974, 2010. DOI: 10.1002/chem.201001705.
For further information, please contact:
School of Chemistry
University of Sydney NSW 2006
Phone: +61 2 9351 2297