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Potential solution to oil spills: Gelling of oil floating on water
Research in collaboration with Prof. George John, City College of NY (2009)

A class of non-toxic sugar-derived organic molecules synthesized by our collaborators can selectively gel a layer of oil floating on water. As shown in the movie, gelation can be done without using heat or shear. Such gelators may find application in the treatment and remediation of oil spills. Moreover, once the oil-gel has been mopped up, the oil can be recovered by distillation. For details, see our paper in Angew. Chem. (2010).

Reversible gelling and ungelling of oil
Research of Hee-Young Lee, Seung-Won Ko and Kevin Diehn (2009)

This movie shows how we can convert a liquid oil, such as kerosene, into a gel, and then convert the gelled oil back to a liquid. In the movie, a gelling agent is squirted onto liquid oil and in a few minutes, the oil spontaneously gets gelled. Thereafter, an ungelling agent (ethanol) is added to the gelled oil, whereupon it is transformed back to its initial liquid state. The science behind this behavior is discussed in our Langmuir (2010) paper.

Tuning the viscosity of a fluid using light
Research of Aimee Ketner and Rakesh Kumar (2007)

Is it possible to switch a fluid from a thick jelly-like state to a thin water-like solution by shining light? And moreover, can such a fluid be made using simple, cheap chemicals? We show that this can be done in our our JACS (2007) paper, where the "recipe" for the fluid depicted in this movie is given. In the movie, our photoresponsive fluid is shown to be initially very viscous, but it becomes very thin and pourable upon UV irradiation.

Targeting of magnetic capsules from a flowing fluid
Research of Jae-Ho Lee and Matt Dowling (2006)

We have developed biopolymer capsules with embedded magnetic nano-particles for use in targeted drug delivery. Here, the ability to target these capsules to a given location from a flowing fluid is demonstrated with large capsules (~ mm size). The capsules are flowing in water from left to right when they are arrested and directed by a magnet..

Persistence of shear-induced birefringence in a wormy micellar fluid
Research of Brad Frounfelker and Gokul Kalur (2004)

Wormy micelles are flexible, polymer-like chains formed by self-assembly of surfactants. When sheared, the chains align and the sample becomes birefringent, but this usually goes away when the shear is stopped. This movie shows an unusual micellar fluid that remains intensely birefringent long after the shear is stopped. The phenomenon is explained in our paper in Langmuir (2009).

© 2007 Srinivasa Raghavan |
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