AskNature

The Challenge

Most crystals such as snowflakes grow in a reliable, consistent, symmetry. This symmetry arises from having a unit cell that consistently repeats throughout the crystalline flake. Although this is useful in most instances, it is challenging for scientists and engineers to control crystal growth, which can impede their ability to solve specific problems.

Innovation Details

The crystal growth chemically manipulates the macromolecular structure so that this translational symmetry is broken when the molecule crystallizes. It uses “bottle-brush” shaped polymers as the crystal’s structural system, which provides scientists a way to control the different types of growth.

“What we’ve discovered is a way to chemically manipulate the macromolecular structure so that this translational symmetry is broken when the molecule crystallizes,” Li said. “This means we can control the overall shape of the crystal as it forms.”

Biomimicry Story

Translational symmetry is found in mineral crystals and snowflakes. The crystals have a repeated unit cell that manifests itself into macroscopic crystals. Other examples of translational symmetry can be found in viral capsid structures and in the honeycombs of bees.

See Related Strategy

Biological Strategy

Controlled Crystal Symmetry

Calcareous sponge

Crystals in glass sponges exhibit controlled growth due to biologically induced reduction in calcitic crystal symmetry.

Biological Strategy

Capsid Proteins Self-assemble to Form Stable Shell

Capsids, the containers housing viral DNA, are stable, self-assembling structures because they rely on the net strength afforded by a combination of weak attractive or repulsive forces arising from the relative position of proteins making up the container