Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New polyelectrolyte inks create fine-scale structures through direct writing

25.03.2004


Direct-write assembly of 3-D micro-periodic structures. (a) Schematic illustration of the ink deposition process. (b) Three-dimensional periodic structure with a face-centered tetragonal geometry (filament diameter: 1 micron). Images courtesy Jennifer Lewis



Like spiders spinning webs, researchers at the University of Illinois at Urbana-Champaign are creating complex, three-dimensional structures with micron-size features using a robotic deposition process called direct-write assembly.

As reported in the March 25 issue of the journal Nature, Jennifer Lewis and her research team have developed novel inks that readily flow through micro-capillary nozzles and then rapidly solidify to retain their shape. Patterning such fine structures could be useful in applications such as drug-delivery, micro-fluidics, photonics and tissue engineering.

"This research builds upon our previous work with colloid-based inks, and represents a major step forward in both ink design and pattern resolution," said Lewis, a Willett Faculty Scholar and a professor of materials science and engineering and of chemical and biomolecular engineering at Illinois. "Because this new ink is based solely on polyelectrolyte mixtures rather than colloidal particles, we are able to produce three-dimensional periodic structures with feature sizes that are 100 times smaller than before."



The smallest feature size Lewis’ team has demonstrated so far is 500 nanometers. An entire three-dimensional structure can fit in the diameter of a human hair.

"The new inks are low-viscosity fluids created by combining oppositely charged polyelectrolyte complexes," Lewis said. "The ink viscosity can be tailored over a wide range to control its flow through fine deposition nozzles of varying diameter."

A spider creates its web by secreting a concentrated protein solution through its spinneret to produce fine silk filaments. "We drew inspiration from this natural process to guide our ink design," said graduate student Gregory Gratson, who helped develop the inks. "For example, we worked in a similar concentration range as spider-spinning dope, though our ink structure is significantly less complicated."

To produce the desired three-dimensional structure, the extruded ink is deposited into a coagulation reservoir containing deionized water and isopropyl alcohol, Gratson said. Solidification of the ink is induced by electrostatic interactions in a water-rich reservoir or by solvent-quality effects in an alcohol-rich reservoir. A careful balance is needed so that the extruded ink filament is elastic enough to maintain its shape while spanning the structure, but flexible enough to adhere to other filaments. Dispensed from a syringe by a computer-controlled, three-axis micropositioner, the polyelectrolyte ink exits the nozzle as a continuous filament that is deposited into a reservoir on the substrate surface, yielding a two-dimensional pattern. After the first layer is generated, the nozzle is raised and another layer is deposited. This process is repeated until the desired three-dimensional structure is produced.


The precisely patterned parts could be used as bio-scaffolds, micro-fluidic networks, sensor arrays or templates for photonic materials.

Graduate student Mingjie Xu is also a co-author of the paper. The U.S. Department of Energy and the U.S. Army Research Office MURI program funded this work.

James E. Kloeppel | UIUC
Further information:
http://www.news.uiuc.edu/news/04/0324inks.html

More articles from Materials Sciences:

nachricht Nagoya University researchers break down plastic waste
29.05.2017 | Nagoya University

nachricht A new tool for discovering nanoporous materials
23.05.2017 | Ecole Polytechnique Fédérale de Lausanne

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Strathclyde-led research develops world's highest gain high-power laser amplifier

The world's highest gain high power laser amplifier - by many orders of magnitude - has been developed in research led at the University of Strathclyde.

The researchers demonstrated the feasibility of using plasma to amplify short laser pulses of picojoule-level energy up to 100 millijoules, which is a 'gain'...

Im Focus: Can the immune system be boosted against Staphylococcus aureus by delivery of messenger RNA?

Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.

Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....

Im Focus: A quantum walk of photons

Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.

The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

 
Latest News

New insights into the ancestors of all complex life

29.05.2017 | Earth Sciences

New photocatalyst speeds up the conversion of carbon dioxide into chemical resources

29.05.2017 | Life Sciences

NASA's SDO sees partial eclipse in space

29.05.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>