- Post Doctoral
MIT Unit Affiliation:
- Chemical Engineering
Post Doc Sponsor / Advisor:
Date PhD Completed:
Top 3 Areas of Expertise:
Expected End Date of Post Doctoral Position:
My key research contributions focus on smart and stimuli responsive materials as a sophisticated approach to controlling the physicochemical properties of colloidal systems suitable for specialized applications ranging from drug delivery and biomedical engineering to separations and advanced coatings. I have extensive experience in the synthesis of ionic liquids, surfactants, polymers and nanoparticles and the generation of various colloidal systems which I characterize using small-angle neutron scattering (SANS), light scattering and surface tensiometry. I have applied these techniques to prepare the first magnetic ionic liquid surfactants, which attracted world-wide media coverage.
Other research includes:
1) ionic liquid drug formulations
2) the synthesis of novel CO2-reactive ionic liquid surfactants for CO2 sequestration, and reversible DNA compaction
3) supercapacitor design using novel ionic liquids
4) spin-glasses from surfactant micelles
5) Water puification using liquid/liquid extraction and electrochemistry
Surfactants comprise one of the largest volume commodity chemicals in the world and have multifarious uses from pharmaceuticals, agrochemicals, food, fuel and lubricant additives, paints and inks as well as detergents and cleaning agents. The ability to control surfactants once they are in solution is of great importance not only for scientific reasons but also because of environmental and economic interest. To this end, surfactants sensitive to changes in pH, temperature, CO2, light and redox have already been developed. This thesis investigates a new class of surfactants designed to be magnetically active, whereby the composition and physico-chemical properties of a system may be perturbed simply by the switching “on” and “off” of a magnetic switch and with no significant energy input.
The thesis demonstrates that these new magneto-responsive surfactants behave like conventional surfactants but are now bifunctional allowing for new magnetic approaches where previously magnetic nanoparticles have been employed. For example, the magnetic properties makes it easier to round up and remove the surfactant from a system once it has been added. By developing the first nanoparticle-free magnetic emulsions the potential for further applications in environmental clean ups (e.g. oil spills), water treatment or drug delivery have been demonstrated. In addition to this, the combination of surfactant adsorption and intrinsic magnetism has allowed for the control and manipulation of biomolecules without the need for magnetic nanoparticles.
This work explores both the fundamental properties of these novel surfactants and also takes significant steps to optimize the surfactants for potential applications.
Top 5 Awards and honors (name of award, date received):
5 Recent Papers:
Brown, P., et al., (2016) "Magnetic surfactants as molecular based-magnets with spin glass properties", J. Phys.: Condens. Matter. - Accepted
Brown, P., et al., (2015) "Magnetic Surfactants and Polymers with Gadolinium Counterions for Protein Separations", Langmuir, 32, 699-705
Brown, P., et al., (2015) "Magnetic Surfactants", Curr. Opin. Coll. Int. Sci., 20, 140-150.
Ranka M., Brown P., Hatton, T. A., (2015) "Responsive Stabilization of Nanoparticles for Extreme Salinity and High Temperature Reservoir Applications", Appl. Mater. Inter., 7, 19651-19658.
Brown, P., et al., (2015) "Enhanced gravimetric CO2 capacity and viscosity for ionic liquids with cyanopyrrolide anion", AiChE J., 61, 2280-2285.