Blending up New Materials - Penn Engineering Blog

A researcher in a lab coat, goggles and nitrile gloves inspects a piece of complicated machinery. — Yale University graduate student Kristof Toth with the electrospray deposition tool he designed, built, and validated in collaboration with Gregory Doerk and Kevin Yager of Brookhaven Lab’s Center for Functional Nanomaterials and Chinedum Osuji of Penn Engineering’s Department of Chemical and Biomolecular Engineering.

The design of new materials is all about achieving the right mix of properties from their constituent parts, whether they’re atoms and molecules, or more complex structures, such as nanoparticles or polymers. But because the desired properties often stem from nanoscale features and patterns, the components can’t just be thrown into a kitchen blender.

With the necessary precision in mind, Chinedum Osuji, Eduardo D. Glandt Presidential Professor in the Department of Chemical and Biomolecular Engineering, has collaborated with researchers at the U.S. Department of Energy’s Brookhaven National Laboratory (BNL) and Yale University to develop a automated tool for creating structurally complex thin films. Three different components can be loaded into syringe pumps, mixed to specification, then sprayed as tiny electrically charged droplets onto a substrate. By coordinating the flow rates of the pumps and the motion of the substrate, the tool can create films with continuous gradients of the different components.

Assembling the components of a new material is only the start of the process, however, as its exact structure needs to be analyzed to make sure those components came together correctly. This is no small feat when the relevant features measure in the billionths of a meter.

To address this aspect, Osuji and his colleagues made some upgrades to their tool, as described by Ariana Manglaviti in the BNL Newsroom:

Now, the team has combined this electrospray deposition tool with the structural characterization technique of x-ray scattering. Together, these capabilities form a platform to probe how material structure changes across an entire composition space. The scientists demonstrated this platform for a thin-film blend of three polymers—chains made of molecular building blocks linked together by chemical bonds—designed to self-assemble into nanometer-scale patterns. Their platform and demonstration are described in a paper published today in RSC Advances, a journal of the Royal Society of Chemistry .

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Though the team focused on a self-assembling polymer system for their demonstration, the platform can be used to explore blends of a variety of materials such as polymers, nanoparticles, and small molecules. Users can also study the effects of different substrate materials, film thicknesses, x-ray beam focal spot sizes, and other processing and characterization conditions.

“This capability to survey a broad range of compositional and processing parameters will inform the creation of complex nanostructured systems with enhanced or entirely new properties and functionalities,” said co-author Chinedum Osuji, the Eduardo D. Glandt Presidential Professor of Chemical and Biomolecular Engineering at the University of Pennsylvania.

Read more at the BNL Newsroom.