ScienceShot: Chalk + Glass = Beauty

16 May 2013 3:51 pm

  • Credit: Image courtesy of Wim Noorduin

    Microbouquet. The "flowers" in this false-color SEM image were grown by nucleating the growth of green stems within purple vases and then changing growth conditions to open the stems into petals (blue).

  • Credit: Image courtesy of Wim Noorduin

    Combo flower. These "flowers" are made by first growing the corallike structure at the bottom (red), then nucleating green spirals within the coral’s folds. Finally, a pulse of added CO2 causes the spirals to flare out into petals (purple).

  • Credit: Image courtesy of Wim Noorduin

    Rose by another name. Changing the conditions of how glass and chalk grow allowed the formation of complex coral shapes atop a spiral, creating what looks like a rose in this false color SEM image.

  • Credit: Image courtesy of Wim Noorduin

    Instant forest. Exposing an aqueous solution containing barium chloride and waterglass (sodium silicate) to CO2 in the air creates a landscape of microscopic "flowers."

Over the years, materials researchers have managed to assemble a handful of simple shapes, such as rods, spheres, and tetrapods, by growing materials from the bottom up an atom at a time. But the ability to grow complex shapes on demand has been limited. Now, scientists have discovered a simple set of design rules for controlling how two different materials—basically chalk and glass—assemble together. Turn the knobs of a solution’s pH, temperature, or the amount of CO2 present and you can alter the way the material grows, changing, for example, from a spiral that resembles a stem, to what looks like a leaf, or even a blooming flower. By turning those dials at just the right time, the researchers grew a variety of luscious-looking blooms that resemble tulips, crocuses, and roses. Discovering similar design rules for magnetic, metallic, and electronic materials, the researchers say, may allow them to pattern catalytic materials and electronic devices over entire surfaces—for making things like cheap solar cells—by simply controlling the conditions under which they are grown.

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