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A D V A N C E D M A T E R I A L S & P R O C E S S E S | O C T O B E R 2 0 1 7 1 2 COUNTERINTUITIVE COMPOSITES MIMIC NATURE While adding a softer substance to a solid typically decreases its elastic modulus, researchers at Rice University, Houston, and the Indian Institute of Sci- ence at Bangalore, found that infusing a polymer with tiny bubbles of liquid had the opposite effect. The team modeled their counterintuitive composite on bi- ological structures that employ both solid and liquid components to create a combination of stiffness and flexibil- ity, such as spinal discs composed of a tough outer cartilage layer covering a soft, jelly-like interior, and the skin of some deep-sea aquatic creatures that contains myriad microscopic oil-filled chambers. To make the material, the team encapsulated pockets of gallium—liq- uid at room temperature—in the clear, nontoxic, and flexible silicon-base polymer, polydimethylsiloxane (PDMS). Coin-size, 0.25-in. thick test samples containing droplets of different sizes and configurations were subjected to dozens of tests. A dynamic mechan- ical analysis instrument determined deformation under load and charac- teristics including stiffness, tough- ness, and elasticity were measured under various conditions. Finite el- ement modeling and hydrodynam- ic simulations rounded out the anal- ysis, which ultimately demonstrated that the liquid gallium gave the com- posite higher energy absorption and dissipation characteristics than plain PDMS or PDMS with air-filled pockets. Such composites could find applica- tion in high-energy absorption materi- als and biomimetic structures. rice.edu , www.iisc.ac.in . NEW DIRECTIONS IN FERRO- ELECTRIC NANOSTRUCTURE An international team led by sci- entists at Nagoya University, Japan, devised a new method to control the domain structure of ferroelectric ma- terials, a vital step in the development of next-gen- eration functional nano- scale devices. Ferroelec- tric materials contain re- gions in their crystal lat- tice that can be toggled by an electric field, chang- ing the position of atoms and switching polariza- tion direction. To organize the behavior of these do- mains, crystals are typi- cally grown on supporting substrates. In their exper- iments, the Nagoya-led Charge screening in ferroelectric Pb(Zr,Ti)O 3 nanorods is used to control their domain pattern. The c-domain fraction markedly increases as rod width decreases, while the a-domain formation prevails by metallization of its sidewall. EMERGING TECHNOLOGY Advanced materials manufacturer Ocsial, Luxembourg, and the Luxembourg government are collaborating to construct a new center for applied nanotechnology. The manufacturing and R&D complex will include a production facility for single-walled car- bon nanotubes with annual capacity of 275 tons. The facility’s first stage is slated to launch in 2020. ocsial.com . BRIEF team grew films of lead zirconate tita- nate on different substrates to induce different kinds of physical strain. They selectively etched parts of the films, leaving freestanding nanorods on the substrates, and used synchrotron x-ray radiation to probe the domain structure of individual rods. It was revealed that after etching, the contact area between the rods and the substrate was greatly reduced, al- lowing the surrounding air to influence their domain properties. In fact, the do- main structure of the nanorods was al- most completely flipped compared to the thin film. The team found that they could induce the rods to recover their original, substrate-determined domain structure by coating themwith metal to screen the effects of the environment. Until now, few effective methods were available for manipulating the domain structure of ferroelectric materials. en.nagoya-u.ac.jp . Nature inspired the design of silicone and gallium composites created at Rice University. Courtesy of Je„ Fitlow/Rice.