Tiny crystal flowers grow in a beaker
Scientists at Harvard have coaxed microscopic crystal flowers to form in a beaker of fluid.
False-coloured, the flowers bloom almost smaller than the naked eye can see.
(Credit: Wim L. Noorduin, Harvard SEAS)
Scientists at Harvard have coaxed microscopic crystal flowers to form in a beaker of fluid.
When one thinks of the word "crystal", you think, perhaps, of wedges of quartz stone, ice crystals and salt — not organic, flowing forms or flowers. But, by manipulating chemical gradients in a beaker of fluid, postdoctoral fellow Wim L, Noorduin at the Harvard School of Engineering and Applied Sciences has managed to control the growth of barium carbonate crystals to form very controlled sculptures of flowers, with petals, stems and leaves.
How the crystal forms is dependent on the mixture of chemicals in a solution. As the chemical gradients react, the pH can change, causing the crystals to grow away from or towards the gradient — enabling Noorduin to coax the forms into leaves radiating outward, a ling, thin stem or the petals of the flower head.
To create the crystals, the team dissolved barium chloride and sodium silicate in a beaker of liquid. Carbon dioxide, naturally dissolving into the liquid, sets of a reaction that precipitates the formation of barium carbonate. Additionally, it lowers the pH balance immediately around the crystals, adding a layer of silica and allowing the crystals to continue to form.
The work, said Noorduin, is to help understand self assembly, which has potential as a means of revolutionising the manufacture of tiny electronics. "For at least 200 years, people have been intrigued by how complex shapes could have evolved in nature," he said. "This work helps to demonstrate what’s possible just through environmental, chemical changes."
The entire research paper, called "Rationally Designed Complex, Hierarchical Microarchitectures", can be read online in the journal Science.
