A different orientation

A

researcher and her colleagues announced recently in the journal

that they have created self-assembling mixtures of nanoparticles and polymer layers that spontaneously assume different orientations. Their findings have applications in such areas as chemical sensing, data storage, and photonic materials.

While self-assembling processes are common in biological systems, such multiple-step processes are difficult to engineer synthetically. Previous research required intervention at each step of the process, but Anna Balazs, Robert Von der Luft Professor in the Department of Chemical and Petroleum Engineering in Pitt's School of Engineering and her team created a two-step process that only requires one intervention.

"What is unique about this study is that it has two interlocking self-assembling steps," said Balazs, who is also a researcher in Pitt's Institute for NanoScience and Engineering. "This is one-stop shopping."

The researchers began with thin films of copolymers - two types of polymer joined together - spread onto a surface. When equal amounts of each polymer are present, the copolymers arrange themselves into layers. If one polymer has an affinity for the surface the film is on, the layers will run parallel to the surface (horizontally); if neither of them "likes" that substrate, the layers will be vertical.