Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Colloidal inks form self-supporting scaffolds through robocasting

20.06.2002


A new way to assemble complex, three-dimensional structures from specially formulated colloidal inks could find use in advanced ceramics, sensors, composites, catalyst supports, tissue engineering scaffolds and photonic materials.



As will be reported in the July 9 issue of the journal Langmuir, scientists have developed colloidal, gel-based inks that form self-supporting features through a robotic deposition process called robocasting. A computer-controlled robot squeezes the ink out of a syringe, almost like a cake decorator, building the desired structure layer by layer.

"Our goal is to make designer materials that can’t be made by conventional forming techniques," said Jennifer Lewis, a professor of materials science and engineering and of chemical engineering at the University of Illinois at Urbana-Champaign.


The work is a collaboration between Lewis, Illinois graduate student James Smay, and Joseph Cesarano, a staff scientist at the U.S. Department of Energy’s Sandia National Laboratories in Albuquerque, N.M. Cesarano pioneered the concept of robocasting several years ago and implemented it as an alternative "rapid prototyping" method for producing ceramic components. The Illinois-Sandia group is advancing the technique to finer scales and designing special inks that can form self-supporting features.

"The directed assembly of fine-scale, three-dimensional structures containing spanning elements required the development of concentrated colloidal, gel-based inks," Lewis said. "These inks must first flow through a very fine deposition nozzle and then quickly ’set’ to maintain their shape while simultaneously bonding to the underlying layer."

The researchers have created structures with features as small as 100 microns (about the diameter of a human hair) and have spanned gaps as large as 2 millimeters.

The elastic properties and the viscous response of the ink can be "tuned" by tailoring the strength of the interparticle attractions, Lewis said. Because of the dynamic nature of the resulting gel, the particle network forms very quickly after the ink is pushed through the syringe, providing the desired shape retention.

Through careful control of colloidal forces, the researchers not only can produce complex shapes that can’t be made by conventional molding or extrusion processes, they also can build in complexity with respect to chemical composition.

"The robotic deposition equipment has the capability of handling multiple inks and dispensing them simultaneously," Lewis said. "As the relative rates of deposited ink are regulated, structures can be built that have compositional variations in them."

Inks are housed in separate syringes mounted on the robotic deposition apparatus and can be mixed or deposited independently. The ink exits the nozzle as a continuous, rod-like filament that is deposited onto a moving platform, yielding a two-dimensional pattern. After a layer is generated, the stage is raised and another layer is deposited. This process is repeated until the desired structure is produced. The machine’s motion is controlled by a computer program called RoboCAD, developed by Smay. The software allows users to rapidly design and build complex, three-dimensional structures by simply designing layers as two-dimensional drawings.

"Ink can be made from nearly any particulate material that can be suspended in solution, as long as the interparticle forces can be tuned to yield the desired viscoelastic response," Lewis said. "We have made inks out of silica, alumina, lead zirconate titanate, and hydroxyapatite (the basic inorganic constituent of bone) colloidal particles. We also can deposit polymeric, metallic, and semiconducting colloidal inks."


The National Science Foundation and the Department of Energy funded this work

James E. Kloeppel | EurekAlert!

More articles from Materials Sciences:

nachricht The stacked colour sensor
16.11.2017 | Empa - Eidgenössische Materialprüfungs- und Forschungsanstalt

nachricht Counterfeits and product piracy can be prevented by security features, such as printed 3-D microstructures
16.11.2017 | Karlsruher Institut für Technologie (KIT)

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

Im Focus: Wrinkles give heat a jolt in pillared graphene

Rice University researchers test 3-D carbon nanostructures' thermal transport abilities

Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

NASA detects solar flare pulses at Sun and Earth

17.11.2017 | Physics and Astronomy

NIST scientists discover how to switch liver cancer cell growth from 2-D to 3-D structures

17.11.2017 | Health and Medicine

The importance of biodiversity in forests could increase due to climate change

17.11.2017 | Studies and Analyses

VideoLinks
B2B-VideoLinks
More VideoLinks >>>