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NASA challenges ‘makers’ to design 3-D printed habitats for deep-space exploration

One concept for a 3D-printed Moon habitat (credit: NASA)

NASA and the National Additive Manufacturing Innovation Institute (America Makes) are holding a new $2.25 million competition, the 3-D Printed Habitat Challenge, to design and build a 3-D printed habitat for deep space exploration, including the agency’s journey to Mars.

The program is designed to advance the additive construction technology needed to create sustainable housing solutions for Earth and beyond. The idea is to avoid taking along materials and equipment for building a habitat on a distant planet, which would take up valuable cargo space.

The first phase of the competition calls on participants to develop state-of-the-art architectural concepts that take advantage of the unique capabilities 3-D printing offers. A prize purse of $50,000 will be awarded at the 2015 Maker Faire in New York.

“The future possibilities for 3-D printing are inspiring, and the technology is extremely important to deep space exploration,” said Sam Ortega, Centennial Challenges program manager. “This challenge definitely raises the bar from what we are currently capable of, and we are excited to see what the maker community does with it.”

Robot prints a road in front of a hangar for a lunar lander (credit: Behnaz Farahi/NASA)

The second phase of the competition is divided into two levels. The Structural Member Competition (Level 1) focuses on the fabrication technologies needed to manufacture structural components from a combination of indigenous materials (such as Moon regolith) and recyclables, or indigenous materials alone. The On-Site Habitat Competition (Level 2) challenges competitors to actually fabricate full-scale habitats using indigenous materials or indigenous materials combined with recyclables. Both levels are open for registration Sept. 26, and each carries a $1.1 million prize.

Winning concepts and products will help NASA build the technical expertise to send habitat-manufacturing machines to distant destinations, such as Mars, to build shelters for the human explorers who follow. On Earth, these capabilities may be used one day to construct affordable housing in remote locations with limited access to conventional building materials.

 

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3D-printed aerogels enable new energy-storage and nanoelectronic devices

Lawrence Livermore researchers have made graphene aerogel microlattices with an engineered architecture via a 3D printing technique known as direct ink writing (credit: Ryan Chen/LLNL)

Lawrence Livermore National Laboratory researchers have made novel graphene aerogel microlattices with an engineered architecture, using a 3D printing technique known as “direct ink writing.” The research, which could lead to better energy storage, sensors, nanoelectronics, catalysis, and separations, is described in an open-access paper in the April 22 edition of the journal Nature Communications.


Lawrence Livermore National Laboratory | How we 3D-print aerogel

The 3D printed graphene aerogels have high surface area, excellent electrical conductivity, are lightweight, have mechanical stiffness and exhibit supercompressibility (allowing for up to 90 percent compressive strain), and show a ten times improvement over bulk graphene materials and much better mass transport.

Aerogel is a synthetic porous, ultralight material derived from a gel, in which the liquid component of the gel has been replaced with a gas. It is often referred to as “liquid smoke.”

3D printing with graphene oxide (GO) inks

SEM image of a 3D printed graphene aerogel microlattice. Scale bar: 100nm. (credit: Cheng Zhu et al./Nature Communications)

The graphene oxide (GO) inks are prepared by combining an aqueous GO suspension and silica filler to form a homogenous, highly viscous ink. These GO inks are then loaded into a syringe barrel and extruded through a micronozzle to pattern 3D structures.

“Adapting the 3D printing technique to aerogels makes it possible to fabricate countless complex aerogel architectures for applications such as mechanical properties and compressibility, which has never been achieved before, ” said engineer Cheng Zhu, a co-author of the journal article.

Previous attempts at creating bulk graphene aerogels produced a largely random pore structure, excluding the ability to tailor transport and other mechanical properties of the material for specific applications such as separations, flow batteries, and pressure sensors. “Making graphene aerogels with tailored macro-architectures for specific applications with a controllable and scalable assembly method remains a significant challenge that we were able to tackle,” said engineer Marcus Worsley, a co-author of the paper.

In contrast, “3D printing allows for intelligently designing the pore structure of the aerogel, permitting control over mass transport (aerogels typically require high pressure gradients to drive mass transport through them due to small, tortuous pore structure) and optimization of physical properties, such as stiffness,” he said. “This development should open up the design space for using aerogels in novel and creative applications.”

The work is funded by the Laboratory Directed Research and Development Program.

Abstract of Highly compressible 3D periodic graphene aerogel microlattices

Graphene is a two-dimensional material that offers a unique combination of low density, exceptional mechanical properties, large surface area and excellent electrical conductivity. Recent progress has produced bulk 3D assemblies of graphene, such as graphene aerogels, but they possess purely stochastic porous networks, which limit their performance compared with the potential of an engineered architecture. Here we report the fabrication of periodic graphene aerogel microlattices, possessing an engineered architecture via a 3D printing technique known as direct ink writing. The 3D printed graphene aerogels are lightweight, highly conductive and exhibit supercompressibility (up to 90% compressive strain). Moreover, the Young’s moduli of the 3D printed graphene aerogels show an order of magnitude improvement over bulk graphene materials with comparable geometric density and possess large surface areas. Adapting the 3D printing technique to graphene aerogels realizes the possibility of fabricating a myriad of complex aerogel architectures for a broad range of applications.

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First large-scale graphene fabrication

ORNL’s ultrastrong graphene-based material features layers of graphene and polymers  (credit: ORNL)

Fabrication size limits — one of the barriers to using graphene on a commercial scale — could be overcome using a new method developed by researchers at the Department of Energy’s Oak Ridge National Laboratory (ORNL).

Graphene, a one-atom-thick material that is about 100 times stronger than steel by weight, has enormous commercial potential but has been impractical to employ on a large scale, mainly because of size limits and expense.

Now, using chemical vapor deposition, a team led by ORNL’s Ivan Vlassiouk has fabricated polymer laminate (layered) composites containing 2-inch-by-2-inch graphene sheets created from large continuous sheets of single-layer graphene. They were also able to produce graphene-based fibers.

Outperforming current composite materials

Graphene-polymer fiber (credit: ORNL)

The new process eliminates flake dispersion and agglomeration (sticking together) problems. The process has potential to outperform current state of the art composite materials in both mechanical properties and electrical conductivity.

The process also uses 50 times less actual graphene in the polymer, compared to current state-of-the-art samples — a key to making the material competitive in the market, Vlassiouk said.

If the ORNL team can reduce cost and demonstrate scalability, graphene could be used in aerospace (structural monitoring, flame-retardants, anti-icing, conductive), the automotive sector (catalysts, wear-resistant coatings), structural applications (self-cleaning coatings, temperature control materials), electronics (displays, flexible printed electronics, thermal management), energy (photovoltaics, filtration, energy storage) and manufacturing (catalysts, barrier coatings, filtration).

The findings are reported in the journal Applied Materials & Interfaces. Scientists at New Mexico State University were also involved in the research, which was supported by ORNL’s Laboratory Directed Research and Development program.

Abstract of Strong and Electrically Conductive Graphene-Based Composite Fibers and Laminates

Graphene is an ideal candidate for lightweight, high-strength composite materials given its superior mechanical properties (specific strength of 130 GPa and stiffness of 1 TPa). To date, easily scalable graphene-like materials in a form of separated flakes (exfoliated graphene, graphene oxide, and reduced graphene oxide) have been investigated as candidates for large-scale applications such as material reinforcement. These graphene-like materials do not fully exhibit all the capabilities of graphene in composite materials. In the current study, we show that macro (2 inch × 2 inch) graphene laminates and fibers can be produced using large continuous sheets of single-layer graphene grown by chemical vapor deposition. The resulting composite structures have potential to outperform the current state-of-the-art composite materials in both mechanical properties and electrical conductivities (>8 S/cm with only 0.13% volumetric graphene loading and 5 × 103 S/cm for pure graphene fibers) with estimated graphene contributions of >10 GPa in strength and 1 TPa in stiffness.