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Pen-on-Paper Flexible Electronics

Royal Society of Chemistry
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Silver Nanoparticle Inks

Conformal Printing of 3D Electrically Small Antennas

Electrically small antennas (ESA) find use in a wide variety of communications platforms - e.g. mobile phones an other handheld devices, RFID, aerospace and defense systems - but their construction requires advances in printing as well as a robust antenna design so that their operating frequency, size, and system impedance could be easily varied.

Researchers have now demonstrated the conformal printing of electrically small antennas on spherical shapes with a key performance metric (radiation quality factor or Q) that very closely approaches the fundamental limit dictated by physics. more...

New Silver-based Nanoparticle Ink Could Lead To Better Flexible Printed Electronics

A new ink developed by researchers at the University of Illinois allows them to write their own silver linings.

The ink, composed of silver nanoparticles, can be used in electronic and optoelectronic applications to create flexible, stretchable and spanning microelectrodes that carry signals from one circuit element to another. The printed microelectrodes can withstand repeated bending and stretching with minimal change in their electrical properties. more...

A Nanoparticle Glue Gun

Flexible printed electronics and solar-cell arrays promise to be cheaper and more versatile than their rigid counterparts. But their components still need to be linked by tiny metal electrodes in order to get electrons flowing through a device. A new silver-nanoparticle ink could be just the thing for printing high-performance electrical connections for flexible devices. More...

Materials science: Solar cells go round the bend

With high oil prices sparking a surge of interest in alternative energy sources, solar cells have become the subject of intense research. Much of this effort focuses on finding new designs that open up fresh applications. John Rogers and colleagues now report just such a development (J. Yoon et al. Nature Materials 2008) -tiny, ultrathin cells made of silicon that, when fixed in arrays on a flexible substrate, create large, bendy solar cells. More...

A New Flexibility With Thin Solar Cells

Photovoltaic cells, the basic building blocks of solar panels, are more efficient and less costly than ever. But manipulating cells (which are usually made of semiconductor materials) and incorporating them into different panel designs is not necessarily easy. More...

Photonic Materials

Germanium Inverse Woodpile Structure with a Large Photonic Band Gap

May 21, 2007 -- Paul Braun, a University Scholar and a professor of materials science and engineering, and Jennifer Lewis, the Thurnauer Professor of Materials Science and Engineering and interim director of the Frederick Seitz Materials Research Laboratory, have created a germanium inverse woodpile structure that has one of the widest photonic band gaps ever reported. More...

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innovations report

Sol-Gel Inks

Printing 3-D Nanostructures With Sol-Gel Inks

Using a wet chemical process known as sol-gel, researchers at the University of Illinois at Urbana-Champaign, US have developed a method for printing three-dimensional structures of metal oxides with nanoscale features. More...

Sol-gel Inks Produce Complex Shapes With Nanoscale Features

New sol-gel inks developed by researchers at the University of Illinois can be printed into patterns to producage three-dimensional structures of metal oxides with nanoscale features. More...

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Microfluidic Networks / Self-Healing

SciAm 50 - Material World

Cut your finger, and your body starts mending the wound even before you have had time to go and find a Band-Aid. Synthetic materials are not so forgiving, but Nancy R. Sottos, Scott R. White and their colleagues at the University of Illinois at Urbana-Champaign are looking to change all that. They developed a self-healing plastic that contains a three-dimensional network of microscopic capillaries filled with a liquid healing agent. When the material is cracked, the released fluid is hardened by particles of a catalyst that are also sprinkled through-out. The new material can repair minor cracks up to seven times at each location, improving on the group’s previous system (in which the fluid was located in individual pockets) that could repair only one injury at each place. More...
SciAm 50 Awards

Self-Healing Plastic

ScienCentral News and WBKO - Even high tech machines like the space shuttle need the occasional repair. But what if materials like plastics could repair themselves? As this ScienCentral News video reports, scientists are doing just that by imitating how our bodies work to heal small wounds. More...

New Composite Material Built to Repair Itself, Much Like Human Skin

June 19, 2007 -- Creation of polymer composites that can seal tiny cracks as they appear has long been a goal of chemists and engineers. Such materials could be useful in airplane wings, for example, which can develop cracks under the stress of flight. Scientists at Illinois are reporting progress toward that goal. More...

Plastic That Heals Itself

June 11, 2007 -- Researchers at the University of Illinois at Urbana-Champaign (UIUC) have made a polymer material that can heal itself repeatedly when it cracks. It's a significant advance toward self-healing medical implants and self-repairing materials for use in airplanes and spacecraft. More...

Plastics That Seals Its Own Cracks

July 2007 -- Plants and animals can repair themselves thanks to circulatory systems that carry healing agents to wounded tissue. Researchers at the Univ. of Illinois have created a new plastic that fixes itself the same way. The material is embedded with channels about as wide as a human hair. More...

Lab on a Chip

May 2005 -- Our work in direct-write assembly of microfluidic channels was featured in the Royal Society of Chemistry's journal, Lab on a Chip (Volume 5, Number 6, June 2005). The article highlighted the innovative fabrication process of microfluidic channels using a fugitive inks.

Air Force Research Laboratory's Technology Horizons cover article: Funded by the Air Force Office of Scientific Research, a team of scientists developed a technique to fabricate three-dimensional microvascular networks embedded in epoxy. These miniscule networks could have many uses as compact fluidic elements in sensors, chemical reactors, and computers.

Scientists achieve 3-D plumbing on a chip

June 2003 -- Using special ink, heat, epoxy and UV-cured resins, researchers have developed a method for creating three-dimensional plumbing on a millimeter-size chip. More...

Mighty Micromixer

July/August 2003 -- At the University of Illinois at Urbana-Champaign, materials scientist Jennifer Lewis and structural engineering Scott White have developed three-dimensional networks of channels that make fluids flow in ways that today's flat wafers can only dream of. More...

Lost and Found

April 17, 2003 --Lost-wax casting is an ancient trick. A sculptor makes a model in wax of the statue he proposes to cast in, say, bronze. He slathers the wax with plaster, lets the plaster dry, heats the whole thing up to melt the wax, and then drains the wax out leaving a statue-shaped hole into which the liquid bronze can be poured. More...

Organic Ink Helps Scientists "Write" Tiny Fluid Factories

March 24, 2003 -- Researchers have developed a new method of "writing" tiny mazes of pipes in millimeter-size devices. Using special ink, they have successfully manufactured three-dimensional networks of channels that can be used to mix microscopic streams of fluid. The findings, published online today by the journal Nature Materials, could aid in the development of new biosensors or improved "labs-on-chips." More...

Polyelectrolyte Inks

Science & Vie

The French magazine Science & Vie highlighted our work (center right) as a nanoscience image of the year, in their 2004 year-in-review issue.

At the 2003 Fall MRS Meeting, Gregory Gratson received the Gold Award in the MRS Graduate Student Award competition for his presentation entitled "Bio-Inspired Polyelectrolyte Inks for Direct-Write Assembly of 3-D Micro-Periodic Structures". He was one of 15 selected for this prestigious award.

Minaturized 3-D Printing

March 27, 2004 -- A printing technique emulating the way spiders spin silk generates polymer microstructures a hundredth the size of those produced by existing three-dimensional printing technologies. The new fabrication scheme could prove to be a cheaper and more flexible route to building minature constructions, including scaffolds for growing replacement tissues and photonic crystals for optical computing. More...

Science & Technology Concentrates: Writing 3-D Structures

March 29, 2004 -- The "writing" methods for microfabrication are generally confined to two dimensions or plagued by wetting and spreading problems. Jennifer A. Lewis, professor of materials science and engineering at the University of Illinois, Urbana-Champaign, and graduate students Gregory M. Gratson and Mingjie Xu have come up with a method that allows them to write 3-D microperiodic structures directly by using concentrated polyelectrolyte inks. More...

Colloidal Inks

Chemistry Highlights 2002

Our work on directed assembly of 3-D periodic structures via robotic deposition of concentrated colloidal inks was recently selected as one of the top research developments in materials chemistry by Chemical & Engineering News' in their feature article entitled "Chemistry Highlights 2002" (December 16, 2002).

New Look for Colloids

November 2002 -- Jennifer Lewis and co-workers have developed techniques for assembling periodic 3D structures by directly 'writing' them with colloidal inks (Advanced Materials 14,1279–1283; 2002). More...

Self-supporting inks

September 2002 -- Three-dimensional structures have been fabricated using colloidal inks by researchers at the University of Illinois and Sandia National Laboratories [Langmuir (2002) 18(14), 5422-5428]. The structures include self-supporting or spanning elements and were built up layer by layer using a technique called robocasting. More...

3-D Structures From Stable Gels

July 1, 2002 -- Using colloidal gels--inks--as construction materials, researchers at the University of Illinois, Urbana-Champaign, and Sandia National Laboratory in Albuquerque have devised a procedure for building intricate three-dimensional structures with micrometer-sized features and overall dimensions of a few millimeters. The new method may lead to applications in advanced ceramics, photonic materials, catalyst supports, and other areas. More...

Safe Deposits

June 29, 2002 -- A technique developed by Jennifer Lewis and James Smay of the University of Illinois at Urbana-Champaign, and Joseph Cesarano of Sandia National Laboratories in Albuquerque, New Mexico, should allow materials scientists to exercise this sort of control in the future, using colloids. More...

Nanoparticle Halos

Nanoparticles stabilize colloids

January 7, 2002 -- Scientists have discovered a new mechanism for stabilizing suspensions of colloidal particles and have demonstrated a procedure for finely tuning the flow behavior of the suspensions. More...

Nanoparticles Stabilize Colloidal Crystals

October 2001 -- Ask those who have tried to produce photonic bandgap materials in the lab with colloidal suspensions, and you're likely to hear about the cracks that appear as the crystals dry. A discovery by a team of researchers at the University of Illinois may go a long way in solving that problem. More...