martes, 31 de diciembre de 2013

Dragonfly-Like Lenses Grown With Liquid Crystals

Image: A magnification showing the liquid crystal “flower” with a silica bead at the center that generated the pattern. Credit: University of Pennsylvania

Move over cultured pearls: Scientists have successfully grown liquid crystal flowers with grains of sand. These structures resemble insect eyes and could be used as complex lenses.

The researchers working on new nanotech dream of a day when all the complex, tiny parts can just manufacture themselves. Getting that to actually happen is called directed assembly, and a team from the University of Pennsylvania recently made a sweet step forward.

In the past they’d tried creating nanoscale structures using microposts that acted like a trellis to direct growth, according to a university press release. This time, they used silica beads, which are basically polished grains of sand, planted in a pool of transparent liquid crystal. This time they generated patterns of petal-shaped bumps that look like flowers. Each transparent petal can function as a lens.

Physics and astronomy professor Randall Kamien, who worked on the flowers, told Gizmag’s Lakshmi Sandhana that the process was similar to making rock candy, where a stick or string acts like a seed for sugar to make crystals naturally. ”We have just done this on a smaller scale,” Kamien said, “making smaller bits of ordered material cued by smaller elements, like our silica beads.

The research was led by a team that included Kamien, chemical and biomolecular engineering professor Kathleen Stebe, professor of materials science, engineering, chemical and biomolecular engineering Shu Yang, as well as lead author, grad student Daniel Beller. They published their work in the journal Physical Review X (abstract).

You might be wondering what the big deal is about growing a bunch of tiny lenses. It might not be as wearable as cultured pearls or as edible as rock candy, but Gizmag’s Sandhana pointed out that the technique could make producing complex dragonfly-like eyes containing millions of spherical lenses easier, faster and cheaper to achieve.

Picture being able to grow compound lenses that could cover a whole surface, lenses that can heal themselves, or even biosensors that could use the lenses to collect information. All that is a long way off but the scientists did tell Gizmag they think their lenses will go into liquid crystal displays within the next decade.

Nanoflowers Grow in Tiny Garden

Professor Shu Yang also suggested that their lens construction could be incorporated into futuristic metamaterials such as an acoustically invisible cloak. Given how far we are from a real invisibility cloak, I think we’re more likely to see a prosthetic eye with nearly X-ray capabilities first, similar to Mad-Eye Moody’s in the Harry Potter series. Heck, we’ve already got Google Glass.

ORIGINAL: Discovery
by Alyssa Danigelis
Dec 27, 2013

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