Nanotechnology Now

Our NanoNews Digest Sponsors





Heifer International

Wikipedia Affiliate Button


android tablet pc

Home > Press > Dripping faucets inspire new way of creating structured particles: Researchers find new method for making spherical particles, from nanoscale to pinhead-sized — including complex beach-ball-like shapes

This illustration shows how a molten fiber, because of a phenomenon known as Rayleigh instability, naturally breaks up into spherical droplets. Researchers from MIT and UCF have figured out how to use this natural tendency as a way to make large quantities of perfectly uniform particles, which can have quite complex structures.
Image: Yan Liang/Fink Lab
This illustration shows how a molten fiber, because of a phenomenon known as Rayleigh instability, naturally breaks up into spherical droplets. Researchers from MIT and UCF have figured out how to use this natural tendency as a way to make large quantities of perfectly uniform particles, which can have quite complex structures.

Image: Yan Liang/Fink Lab

Abstract:
Researchers at MIT and the University of Central Florida (UCF) have developed a versatile new fabrication technique for making large quantities of uniform spheres from a wide variety of materials — a technique that enables unprecedented control over the design of individual, microscopic particles. The particles, including complex, patterned spheres, could find uses in everything from biomedical research and drug delivery to electronics and materials processing.

Dripping faucets inspire new way of creating structured particles: Researchers find new method for making spherical particles, from nanoscale to pinhead-sized — including complex beach-ball-like shapes

Cambridge, MA | Posted on July 18th, 2012

The method is an outgrowth of a technique for making long, thin fibers out of multiple materials, developed over the last several years at MIT by members of the same. The new work, reported this week in the journal Nature, begins by making thin fibers using this earlier method, but then adds an extra step of heating the fibers to create a line of tiny spheres — like a string of pearls — within these fibers.

Conventional fabrication of microscopic spherical particles uses a "bottom-up" approach, growing the spheres from even tinier "seeds" — an approach that is only capable of producing very tiny particles. This new "top-down" method, however, can produce spheres as small as 20 nanometers (about the size of the smallest known viruses) or as large as two millimeters (about the size of a pinhead), meaning the biggest particles are 100,000 times larger than the smallest ones. But for a given batch, the size of the spheres produced can be extremely uniform — much more so than is possible with the bottom-up approach.

Yoel Fink, a professor of materials science and director of MIT's Research Laboratory of Electronics, whose group developed the earlier method of producing multimaterial fibers, explains that the new method can also produce multimaterial spheres consisting of different layers or segments. Even more complex structures are possible, he says, offering unprecedented control over particle architecture and composition.

The most likely short-term uses of the new process would be for biomedical applications, says Ayman Abouraddy, a former postdoc in Fink's lab who is now an assistant professor at UCF's College of Optics and Photonics. "Typical applications of nanoparticles today are for controlled drug delivery," he says. But with this new process, two or more different drugs — even ones that are ordinarily incompatible — could be combined inside individual particles, and released only once they've reached their intended destination in the body.

More exotic possibilities could arise later, Abouraddy adds, including new "metamaterials" with advanced optical properties that were previously unattainable.

The basic process involves creating a large polymer cylinder, called a "preform," containing an internal semiconductor cylinder core that is an exact scaled-up model of the final fiber structure; this preform is then heated until it is soft enough to be pulled into a thin fiber, like taffy. The internal structure of the fiber, made of materials that all soften at the same temperature, retains the internal configuration of the original cylinder.

The fiber is then heated further so that the semiconducting core forms a liquid, producing a series of discrete spherical droplets within the otherwise continuous fiber. This same phenomenon causes a diminishing stream of water from a faucet to eventually break up into a stream of droplets, famously captured by MIT's Harold "Doc" Edgerton in his stroboscopic images.

Abouraddy says that during a visit to ancient temples in his native Egypt, he found an inscription showing that even long ago, people were aware of this degradation of a stream of water into droplets — caused by a process now known as Rayleigh instability.

In the new fabrication process developed by Abouraddy and Fink's team, these droplets "freeze" in place as the fiber solidifies; the preform's polymer sheath then keeps them locked in place until it is later dissolved away. This overcomes another problem with traditional production of nanoparticles: their tendency to clump together.

In principle, Abouraddy says, the discovery of this process for forming particles could have come many years ago. But even after theorists had predicted that such instabilities could form in the process of drawing fibers, the new discovery came by accident: Joshua Kaufman, a student of Abouraddy's, was trying to produce fibers, but his experiment "failed" when the fiber kept breaking up into droplets.

Abouraddy, who knew about the theoretical possibility, immediately recognized that this "failure" was actually an important discovery — one that had eluded previous attempts simply because the process requires a precise combination of timing, temperature and materials. Kaufman is the lead author of the Nature paper.

"The ability to harness and control the fleeting fluid instability within a fiber has profound implications for future devices," Fink says, and could lead to a wide variety of uses. While the group has demonstrated the production of six-segment "beach ball" particles, in principle much more complex structures, made of a variety of materials, should also be possible, he says. Any material that could be drawn into a fiber could now, in principle, be made into a small particle.

The work was supported by the National Science Foundation, the Air Force Office of Scientific Research and the Army Research Office through MIT's Institute for Soldier Nanotechnologies.

Written by David Chandler, MIT News Office

####

For more information, please click here

Contacts:
Sarah McDonnell
MIT News Office

T: 617-253-8923

Copyright © MIT

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Imaging electric charge propagating along microbial nanowires October 20th, 2014

Design of micro and nanoparticles to improve treatments for Alzheimers and Parkinsons: At the Faculty of Pharmacy of the UPV/EHU-University of the Basque Country encapsulation techniques are being developed to deliver correctly and effectively certain drugs October 20th, 2014

Physicists build reversible laser tractor beam October 20th, 2014

Removal of Limitations of Composites at Superheat Temperatures October 20th, 2014

Govt.-Legislation/Regulation/Funding/Policy

Crystallizing the DNA nanotechnology dream: Scientists have designed the first large DNA crystals with precisely prescribed depths and complex 3D features, which could create revolutionary nanodevices October 20th, 2014

Imaging electric charge propagating along microbial nanowires October 20th, 2014

HP Supercomputer at NREL Garners Top Honor October 19th, 2014

First Canada Excellence Research Chair gets $10 million from the federal government for oilsands research at the University of Calgary: Federal government announces prestigious research chair to study improving oil production efficiency October 19th, 2014

Discoveries

Imaging electric charge propagating along microbial nanowires October 20th, 2014

Design of micro and nanoparticles to improve treatments for Alzheimers and Parkinsons: At the Faculty of Pharmacy of the UPV/EHU-University of the Basque Country encapsulation techniques are being developed to deliver correctly and effectively certain drugs October 20th, 2014

Physicists build reversible laser tractor beam October 20th, 2014

Removal of Limitations of Composites at Superheat Temperatures October 20th, 2014

Materials/Metamaterials

Removal of Limitations of Composites at Superheat Temperatures October 20th, 2014

Nanotechnology Improves Quality of Anti-Corrosive Coatings October 17th, 2014

Graphenea opens US branch October 16th, 2014

3DXNano™ ESD Carbon Nanotube 3D Printing Filament - optimized for demanding 3D printing applications in the semi-con and electronics industry October 16th, 2014

Announcements

Imaging electric charge propagating along microbial nanowires October 20th, 2014

Design of micro and nanoparticles to improve treatments for Alzheimers and Parkinsons: At the Faculty of Pharmacy of the UPV/EHU-University of the Basque Country encapsulation techniques are being developed to deliver correctly and effectively certain drugs October 20th, 2014

Physicists build reversible laser tractor beam October 20th, 2014

Removal of Limitations of Composites at Superheat Temperatures October 20th, 2014

Military

Crystallizing the DNA nanotechnology dream: Scientists have designed the first large DNA crystals with precisely prescribed depths and complex 3D features, which could create revolutionary nanodevices October 20th, 2014

Imaging electric charge propagating along microbial nanowires October 20th, 2014

1980s aircraft helps quantum technology take flight October 20th, 2014

Tailored flexible illusion coatings hide objects from detection October 13th, 2014

Research partnerships

Crystallizing the DNA nanotechnology dream: Scientists have designed the first large DNA crystals with precisely prescribed depths and complex 3D features, which could create revolutionary nanodevices October 20th, 2014

IRLYNX and CEA-Leti to Streamline New CMOS-based Infrared Sensing Modules Dedicated to Human-activities Characterization October 15th, 2014

Scientists Map Key Moment in Assembly of DNA-Splitting Molecular Machine: Crucial steps and surprising structures revealed in the genesis of the enzyme that divides the DNA double helix during cell replication October 15th, 2014

Unique catalysts for hydrogen fuel cells synthesized in ordinary kitchen microwave oven October 14th, 2014

NanoNews-Digest
The latest news from around the world, FREE





  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More














ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project







© Copyright 1999-2014 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE