PHILADELPHIA Directed assembly is a growing field of research in nanotechnology in which scientists and engineers aim to manufacture structures on the smallest scales without having to individually manipulate each component. Rather, they set out precisely defined starting conditions and let the physics and chemistry that govern those components do the rest.
An interdisciplinary team of researchers from the University of Pennsylvania has shown a new way to direct the assembly of liquid crystals, generating small features that spontaneously arrange in arrays based on much larger templates.
The study was led by Shu Yang, associate professor in the School of Engineering and Applied Science's departments of Materials Science and Engineering and Chemical and Biomolecular Engineering; Kathleen Stebe, Engineering's vice dean for research and professor in Chemical and Biomolecular Engineering; and Randall Kamien, professor in the School of Arts and Sciences' Department of Physics and Astronomy. Apiradee Honglawan of Yang's lab, Daniel Beller of Kamien's group and Marcello Cavallaro Jr. of Stebe's lab also contributed to the research.
They came together through Penn's Materials Research Science and Engineering Center, which recently received a $21.7 million National Science Foundation grant to support this kind of interdisciplinary research. Stebe and Kamien are leaders of the Center's sub-group focused on elasticity in soft materials and knew they had the expertise on hand to do groundbreaking work with liquid crystals.
Their work was published in the Proceedings of the National Academy of Sciences.
Crystals are materials that have molecules arrayed in regular three-dimensional patterns; liquid crystals contain some, but not all, of these patterns, and their molecules can flow around one another and change the direction they face. This behavior allows defects, places on the surface where the molecular orien
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University of Pennsylvania