With innovative measurement techniques and new ways to position the molecules, NIST researchers reported at the March Meeting of the American Physical Society how they have improved manipulation of so-called block copolymers—polymers made of a mixture of two or more different molecule building blocks that are tethered at a junction point—which can form arrays of tiny dots that could be used as the basis for electronic components that pack terabytes (1000 gigabytes) of memory in something as small as a pack of gum.
One of the challenges in polymer nanotechnology is how to control their self-assembly—a hard-to-control process for materials which require precision. An important recent NIST accomplishment has been in developing accurate measurements of thin film polymeric nanostructure in 3-D. (Ironically, while determining atomic structure is well-established, measuring the slightly larger internal structure of the polymers—on the order of 10 to 20 nanometers—is much harder.) Ron Jones, together with colleagues from NIST, the University of Maryland and IBM, has used NIST’s neutron scattering and reflectivity facility to deflect neutrons off block copolymer films from many different angles. By combining the many 2-D neutron scattering pictures into a single composite scattering pattern, this technique provides the first quantitative method for imaging the 3-D internal structure of thin film polymeric nanostructures using neutron scattering—a crucial tool to see if the nanoscale polymer structures are in their required positions.1
NIST researchers also have developed new insights on how best to nudge these self-assembling material into those positions. August Bosse will report on computer simulations that model how the polymers assemble when they are placed on templates lined with troughs separated by crests.2 When a heated zone is swept across the template, the polymer molecules assemble into almost defect free, well-aligned lines faster over the entire template, an important feature for nanotech manufacturing applications.3 Sangcheol Kim (working with a team that included researchers from the University of Maryland and IBM) has found that changing the surface chemistry of the template by making some parts hydrophillic and some parts hydrophobic also can elegantly control the dimension of the block-copolymer pattern relative to the chemical template.4
And last, with all this emphasis on precise placement, NIST researcher Kevin Yager, has learned that sometimes sloppier is better. By purposely roughening up his templates with a sprinkling of chemically modified nanoparticle silica, he has forced block copolymers into standing perpendicular to the template—a feat that is generally considered tough to manage but important for nanotech applications.5 Of course, the inner structure of the polymers are not orderly with this technique, but for those applications where only the surface needs to be smooth, this is an ideal, inexpensive way to achieve vertical structures.
Michael Baum | EurekAlert!
Only an atom thick: Physicists succeed in measuring mechanical properties of 2D monolayer materials
17.01.2018 | Universität des Saarlandes
Black hole spin cranks-up radio volume
15.01.2018 | National Institutes of Natural Sciences
What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...
For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.
Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...
At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.
No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...
Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.
Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...
The oceans are the largest global heat reservoir. As a result of man-made global warming, the temperature in the global climate system increases; around 90% of...
08.01.2018 | Event News
11.12.2017 | Event News
08.12.2017 | Event News
18.01.2018 | Medical Engineering
18.01.2018 | Ecology, The Environment and Conservation
17.01.2018 | Ecology, The Environment and Conservation