Nitash Balsara
Professor of Chemical Engineering

Nanotechnology is considered an emerging field, but it promises to revolutionize everything around us. Derived from the Greek word for midget, “nano” means 10-9, a billionth part. A nanometer (nm), for example, is one billionth of a meter. To get an idea of the scale involved, the diameter of a human hair is 200,000 nm.

However, nanotechnology is not just the study of the very small, it is also technology: the practical application of science. Although they have long been fascinated with atoms, only recently have scientists acquired the ability to manipulate them precisely. Today, researchers painstakingly assemble nanodevices a single molecule at a time. But to be useful, a device would have to contain millions of clusters arranged in just the right configuration. In order to achieve this, scientists are focusing on devices that can assemble themselves based on inherent molecular properties.

Self-Assembling Structures
Self-assembly of nanostructures is dependent upon the availability of a suitable surfactant that can stabilize the interface between the structure and the medium. Using simple chemical reactions, we synthesize polymers and then apply physical principles to achieve specific shapes from the polymer molecules. Oil and water can be mixed to form organized nanostructures such as micelles, vesicles and bilayers. The rich phase behavior found in aqueous systems is due to the availability of different types of amphiphilic molecules (molecules that have a polar water-soluble group attached to a water-insoluble hydrocarbon chain). In contrast, relatively few surfactants are able to stabilize interfaces between non-aqueous phases. Our research in Tan Hall focuses on this shortcoming.

Reducing Landfill
Our long-term goal is to generate a wide variety of surfactants that can stabilize interfaces between normally unmixable polymers. This research could also have a considerable impact in the waste management business, because most commercially important polymers and plastics do not mix with each other. This is a huge problem in recycling. There is an urgent need to solve this problem; with every passing year, we accumulate more unrecycled polymer waste, and the absence of a coherent solution is a growing concern.

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Surfactants at work: polyethylene bubbles in a polypropylene matrix, stabilized by a polymeric surfactant. (Courtesy of the Balsara group.)

 

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