Materials World Network: Study of Macromolecular Ferrofluids

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The Materials World Network for the Study of Macromolecular Ferrofluids brings together an international team of chemists, physicists and engineers to address the design, synthesis and properties of nanostructured polydimethylsiloxane (PDMS) ferrofluids, and to investigate control over the magnetophoretic mobility of their droplets in hydrophilic, immiscible, viscous media. The team includes J. S. Riffle and R. M. Davis, Depts. of Chemistry and Chemical Engineering, VA Tech, Blacksburg, VA, USA and T. G. St. Pierre and R. C. Woodward, School of Physics, and M. A. Saunders, Center for Microscopy and Microanalysis, the University of Western Australia, Perth, AU.The ultimate goals are to employ gradient magnetic fields to maneuver hydrophobic magnetic droplets through aqueous media, and to apply forces with the droplets. The motion and behavior of ferrofluid droplets in an immiscible viscous medium under the influence of magnetic field gradients are complex. To obtain optimal response to applied magnetic fields and field gradients requires optimal design of ferrofluid viscosity, surface tension, magnetic susceptibility, and droplet size. These parameters are determined by the molecular compositions, nanoparticle sizes, dispersant and carrier molecular weights, dispersion characteristics within the droplets with and without a magnetic field, interfacial tension between the fluid and the medium, and the complex fluid properties. Well-defined PDMS-magnetite nanoparticle complexes will be prepared and dispersed in PDMS carriers, with and without the aid of special block copolymer surfactants, to understand their structure-property relationships. One potential application is the use of biocompatible PDMS ferrofluids for applying a magnetic force from inside the eye on a detached retina to press it into place against the underlying choroid, and also to close a hole in the retina. There are also other potential applications of nanostructured ferrofluids in biotechnology such as magnetic field-directed drug carriers, fluids for remote treatment of arterial aneurysms, or liquid ball valves for temporarily closing nanometer to micron size openings. The outcomes of the research are also expected to have potential as ferrofluid-based actuators, electromagnetic micropumps, and fluid based valves and sealing systems. Graduate and undergraduate students will be trained with the teamwork skills and the creativity for tackling complex multi-disciplinary research problems in a global setting. This award is co-funded by the East Asia Pacific Program of the Office of International Science and Engineering.