Craftsmen tile walls or floors by hand; but how can you get an ordered monolayer onto a substrate when the “tiles” are microscopically small instead of big and easy to handle? Previously, self-assembly processes have been the method of choice for this scale. Korean researchers have now come to the realization that even such tiny components can be arranged in a “do-it-yourself” method. As they describe in the journal Angewandte Chemie, their manually produced monolayers of microcrystals are qualitatively superior to the self-assembled variety.
How small can components be such that they can still be glued to a surface by hand? And conversely, how big can microscale components be such that they can still be arranged by self-assembly? Which method is best in the size range in which both techniques work? These questions have been investigated by a team led by Kyung Byung Yoon at Sogang University in Seoul. To find answers, they carried out experiments with variously sized zeolite crystals. Zeolites are aluminosilicate minerals with a wide range of applications in many technical fields.
The powdered zeolite was applied by simply rubbing it on with a finger (with and without wearing a latex glove). Alternatively, they were applied in solution, and ultrasound was used to kick-start the self-assembly process. The “glue” between the “mini-tiles” and the substrate was the attraction between oppositely charged groups of atoms, hydrogen bonds, and chemical bonds between reactive groups of atoms.
The experiments demonstrated that self-assembly only works for particles smaller than about 3 µm. Hand-application works for crystals as small as 0.5 µm in diameter. In the overlapping range (0.5 to 3 µm), hand application is preferable to self-assembly for quality: the packing is denser and the microcrystals are oriented more regularly. Whereas self-assembly produces individual crystals grown at a 90° angle onto the monolayer, such “parasites” are simply rubbed off by hand. There are other “handy” advantages of the manual process as well: it is simpler, doesn’t require a solvent or special equipment, runs more smoothly, and allows treatment of larger surfaces.
Author: Kyung Byung Yoon, Sogang University, Seoul (Korea), http://www.sogang.ac.kr/bbs/faculty/2profile.php?para=101191
Title: Manual Assembly of Microcrystal Monolayers on Substrates
Angewandte Chemie International Edition 2007, 46, No. 17, doi: 10.1002/anie.200604367
| Angewandte Chemie
Further information:
http://pressroom.angewandte.org.
http://www.sogang.ac.kr/bbs/faculty/2profile.php?para=101191
http://www.wiley.co.uk
Further reports about: > monolayer > self-assembly
One step closer to reality
20.04.2018 | Max-Planck-Institut für Entwicklungsbiologie
The dark side of cichlid fish: from cannibal to caregiver
20.04.2018 | Veterinärmedizinische Universität Wien
University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.
Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.
Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.
Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...
Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.
The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...
Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.
Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...
In the fight against cancer, scientists are developing new drugs to hit tumor cells at so far unused weak points. Such a “sore spot” is the protein complex...
Anzeige
Anzeige
Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"
13.04.2018 | Event News
Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018
12.04.2018 | Event News
IWOLIA: A conference bringing together German Industrie 4.0 and French Industrie du Futur
09.04.2018 | Event News
Magnetic nano-imaging on a table top
20.04.2018 | Physics and Astronomy
Start of work for the world's largest electric truck
20.04.2018 | Interdisciplinary Research
Atoms may hum a tune from grand cosmic symphony
20.04.2018 | Physics and Astronomy