Volume 93 Issue 9 | p. 29 | Concentrates
Issue Date: March 2, 2015

Pop-Up Liquid Crystals

Thermal or chemical stimuli prompt liquid-crystal elastomers to transform from flat sheets to three-dimensional objects
Department: Science & Technology
Keywords: liquid crystal, elastomer

A soft material made of liquid crystals attached to an elastic polymer goes from a flat sheet to a three-dimensional object in response to heat or a chemical stimulus (Science 2015, DOI: 10.1126/science.1261019). The material, known as a liquid-crystal elastomer (LCE), could find use in aerospace, medicine, or consumer goods, for example, as packaging material or as a tunable antenna. Liquid crystals are materials that have a fluctuating orientation, like a liquid, but are also aligned, like a crystal. Changes in the optical polarization of the liquid block or transmit light, leading to images on liquid-crystal display television sets. To make that shift one that takes shape in three dimensions, a team at the Air Force Research Laboratory, led by Timothy J. White, used light to pattern and align azobenzene-based liquid crystals and then polymerized them into poly(β-amino ester) networks. Depending on the initial patterning, the resulting LCEs can take on various shapes, such as a conical actuator or a molecular hinge.

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A flat LCE shape shifts into mountains when heated.
Credit: Science
A patterned liquid crystal elastomer takes on a three-dimensional shape when heated.
 
A flat LCE shape shifts into mountains when heated.
Credit: Science
 
Chemical & Engineering News
ISSN 0009-2347
Copyright © American Chemical Society

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