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Materials scientists at MIT have discovered that interfaces within materials can be patterned as a means of controlling the properties of composites and that such control of internal patterns can lead to significant improvements in the performance of the resulting materials.

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Hidden patterns
Since patterned surfaces are popular among researchers seeking to induce surfaces to repel water or adhere to other things, or to modify materials’ electrical properties, materials scientists at MIT have added a new wrinkle to research on the patterning of surfaces. Most research has focused on patterns on the outer surfaces of materials, but a team in MIT’s Department of Materials Science and Engineering have begun to explore the effects of patterned surfaces deep within materials — specifically, at the interfaces between layers of crystalline materials.

While much research has aimed to create layered composites with desired strength, flexibility, or resistance to vibrations, temperature changes, or radiation, actually controlling the surfaces where two materials meet within a composite is a tricky process, the researchers explained. Further, these aren’t thought of as surfaces, and if they are they are thought of as a uniform surface, but as it turns out, most interfaces are not uniform.

To control the properties of these materials, it is essential to understand and direct these nonuniform interfaces, the MIT team asserted. As such, the team took classical equations used to describe average properties of surfaces and adapted them to instead describe variations in these surfaces location by location.

The ability to simulate, and then control, how defects or variations are distributed at these interfaces could be useful for a range of applications including production of thermoelectric devices. Similarly, the creation of pathways for diffusion within a material could help improve the efficiency of devices such as lithium-ion batteries and fuel cells

Interfaces between solid materials are surfaces with intricate, internal structure (shown on the left). To control that structure, and to use it for specific applications, researchers model it a simplified way (shown on the right). (Source: MIT)

Interfaces between solid materials are surfaces with intricate, internal structure (shown on the left). To control that structure, and to use it for specific applications, researchers model it a simplified way (shown on the right). (Source: MIT)