Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > 2-d blueprint into novel 3-d nanostructures

Self-assembling block copolymers extend photolithography to three dimensions

From 2-d blueprint, material assembles into novel 3-d nanostructures

Madison, WI | Posted on January 27, 2006

An international team of scientists affiliated with the University of Wisconsin-Madison Nanoscale Science and Engineering Center has coaxed a self-assembling material into forming never-before-seen, three-dimensional nanoscale structures, with potential applications ranging from catalysis and chemical separation to semiconductor manufacturing.

Led by UW-Madison chemical and biological engineering professors Paul Nealey and Juan de Pablo and colleagues at Georg-August University in Germany and the Paul Scherrer Institute in Switzerland, the team has discovered that materials known as block copolymers will spontaneously assemble into intricate 3-D shapes when deposited onto particular 2-D surface patterns created with photolithography.

The result, published in the Jan. 27 issue of Physical Review Letters, demonstrates a promising strategy for building complex, 3-D nanostructures by using standard tools of the semiconductor industry, says Nealey. Those tools, particularly lithography, already allow the making of devices with dimensions substantially smaller than 100 nanometers, or a hundred-thousandth of a centimeter.

But photolithography is also limited, he says, because as practiced today it is essentially a two-dimensional process.

"What we've done by using self-assembling block copolymers is to extend photolithography to three dimensions," says Nealey. "And the structures we've fabricated are completely different from the same block copolymer materials in the bulk."

Also important to manufacturing, the new 3-D nanostructures are stable, well defined and nearly defect-free over large areas. They also align perfectly with the underlying lithographic pattern-a key requirement for any device or application based on them.

"This research shows that lithography combined with block copolymers is more versatile and powerful than we thought. We can now create completely new structures that will no doubt have new properties and new applications," says de Pablo. "Exactly what those structures will be is anybody's guess; here we demonstrate a complicated one. But the important thing is they open up a new field of exploration, both for these materials and this technology."

The specific structures the team produced were composed of two tightly interwoven, yet completely independent, networks of channels and passages-all at the scale of atoms. "What we have are two interpenetrating meshes, both of which are completely continuous. And yet you could travel through one from end to end without ever entering the other," says de Pablo.

The networks are also in perfect register with the photolithographic pattern underneath, which tells scientists exactly where each channel ends and gives them ready access to channel openings. A gas, for example, might be introduced through the openings to react with a catalyst deposited on the walls of the network. Nanoscale materials have massive surface areas compared to their volumes; thus, catalysis would be extremely efficient.

Another use would be chemical separation of substances of different sizes. "This process gives us exquisite control over the dimensions of pores," says de Pablo. "So, we could easily make membranes that are permeable to substances smaller than the length scale of the material."

The researchers study specific block copolymers consisting of long chains of two different types of molecules, which alternate with each other in blocks. At high temperature, block copolymers are molten and randomly mixed. But when cooled down, the material spontaneously assembles into alternating layers of molecules.

This work was supported by the National Science Foundation Nanoscale Science and Engineering Center at the University of Wisconsin and the Semiconductor Research Corporation.

Paul Nealey
(608) 265-8171

Copyright University of Wisconsin-Madison

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.

Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

Self Assembly

First multicellular organism inspires the design of better cancer drugs September 15th, 2016

A versatile method to pattern functionalized nanowires: A team of researchers from Hokkaido University has developed a versatile method to pattern the structure of 'nanowires,' providing a new tool for the development of novel nanodevices September 9th, 2016

Location matters in the self-assembly of nanoclusters: Iowa State University scientists have developed a new formulation to explain an aspect of the self-assembly of nanoclusters on surfaces that has broad applications for nanotechnology September 8th, 2016

Smarter self-assembly opens new pathways for nanotechnology: Brookhaven Lab scientists discover a way to create billionth-of-a-meter structures that snap together in complex patterns with unprecedented efficiency August 9th, 2016


KaSAM-2016: International Conference on Material Sciences has successfully concluded in Pokhara of Western Nepal October 24th, 2016

Move over, solar: The next big renewable energy source could be at our feet October 20th, 2016

Smashing metallic cubes toughens them up: Rice University scientists fire micro-cubes at target to change their nanoscale structures October 20th, 2016

Study explains strength gap between graphene, carbon fiber: Rice University researchers simulate defects in popular fiber, suggest ways to improve it October 19th, 2016


When quantum scale affects the way atoms emit and absorb particles of light: Exact simulation lifts the 80-year-old mystery of the degree to which atoms can be dressed with photons October 24th, 2016

Nanoantenna lighting-rod effect produces fast optical switches October 24th, 2016

New nanomedicine approach aims to improve HIV drug therapies October 24th, 2016

New method increases energy density in lithium batteries: Novel technique may lead to longer battery life in portable electronics and electrical vehicles October 24th, 2016

The latest news from around the world, FREE

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

Nanotechnology Now Featured Books


The Hunger Project