Starfish-Like Shells Could Lead to Advanced Technologies

Engineers from the University of Michigan have created starfish-like shells that could lead to advanced technologies, according to new research.

"We call them nanolobes. They look like little hot air balloons that are rising from the surface," Olga Shalev, a doctoral student involved in developing the design, said in a statement.

Described in the journal Nature Communications, nanoscale shapes are made out of boron subphthalocyanine chloride, a material often used in organic solar cells. They are round crystals with no facets, which in itself doesn't sound like much but is actually a breakthrough in the engineering world.

The design mimics the shells of echinoderm sea creatures such as brittle stars, which have rounded structures on their bodies that work as lenses to gather light into their eyes. In a lab, creating crystals of the same minerals, however, either results in a faceted shape with flat faces or a rounded shape lacking molecular order.

"In my years of working with these kinds of materials, I've never seen shapes that looked like these. They're reminiscent of what you get from biological processes," explained associate professor Max Shtein. "Nature can sometimes produce crystals that are smooth, but engineers haven't been able to do it reliably."

Researchers stumbled upon the new nanolobe design by accident, and have since then perfected the process.

The key to their success was the thickness of the material. At 800 nanometers thick, the repeating nanolobe pattern emerged every time, according to researchers.

Both the nanolobes' shape and the way they're made have promising applications, the authors add. The geometry could potentially be useful to guide light in advanced LEDs, solar cells and nonreflective surfaces.

A layer might also help a material repel water or dirt. And the process used to manufacture them - organic vapor jet printing - might lend itself to 3D-printing medications that absorb better into the body and make personalized pills and dosing possible.