Minerals assemble themselves into exquisite nanoscale flower bouquets.
The shapes that materials in nature take on are determined by some simple rules of chemistry. Basically, if you can change a solution’s temperature, the amount of CO2 or its pH—that is, its acidity and alkalinity—you can actually alter the way a material grows. In an elegant study conducted by chemists at Harvard, tiny floral structures have been fashioned by manipulating these conditions in a beaker containing chalk, glass and water.
“When you look through the electron microscope, it really feels a bit like you’re diving in the ocean, seeing huge fields of coral and sponges,” described lead researcher Wim Noorduin in a Harvard press statement. “Sometimes I forget to take images because it’s so nice to explore.”
The scientists used an instrument called a scanning electron microscope (SEM) to see the tiny structures self assemble. They noticed some interesting patterns that occurred as a result of changing the conditions in the beaker. For example, when the concentration of carbon dioxide was increased, the minerals developed a “broad leafed” structure and reversing the pH gradient created curved, ruffled petal shapes. Each individual flower is roughly fifty micrometers high, which is around the width of a strand of human hair.