A simple trick generates custom-tailored pores. Maryam Radjabian has developed a surprisingly uncomplicated method for obtaining the desired pore size in block copolymer membranes. The results of her research were published in the distinguished international scientific journal Advanced Materials.
Whether it’s water treatment or virus and protein separation, porous membranes are utilised in many different separation functions. What is particularly fascinating and highly promising is isoporous membrane production from block copolymers.
Under suitable conditions, block copolymers can form highly ordered structures, ideally uniform pores, through self-assembly (see “Block Copolymer Information” below).
In order to develop effective membranes for special separation functions, the correct pore size is crucial. This objective presents the greatest challenge: how must the block copolymer be composed in order to obtain the desired pore size?
To date, for every newly developed isoporous membrane a special block copolymer was synthesized, which then resulted in the necessary pore size. In cooperation with the director of Geesthacht’s Institute of Polymer Research, Prof. Volker Abetz, Dr. Maryam Radjabian has now developed a time-saving and surprisingly simple method: by blending of two block copolymers, the pore size can be adjusted via the blending ratio.
The two block copolymers consist of the same monomers but differ in the number of repetition units in the blocks. A different pore size then arises in the particular membrane cast from each block copolymer. Dr. Radjabian’s concept of obtaining an average pore size by blending two block copolymers has been corroborated in experiments.
This opens up entirely new possibilities for designing new membranes. The scientist at the Institute of Polymer Research explains, “There is a substantial advantage in not having to synthesize a precisely suitable block copolymer to obtain the desired pore size, but in simply mixing two approximately suitable copolymers together.”
Block Copolymer Information:
Block copolymers consist of at least two types of monomers, each covalently linked together as polymer blocks (a group of the same monomers) in the form of a macromolecule. Because the blocks of macromolecules are selected so that they are not mixable (“immiscible”), self-assembly of the macromolecules takes place through rejection reactions (microphase separation).
Isoporous Membranes can be produced from a block copolymer solution under defined conditions by utilising the phase inversion principle. The foundations for this research were developed within the HZG-coordinated European Union project SELFMEM (2009-2012).
DOI: 10.1002/adma.201404309: Tailored Pore Sizes in Integral Asymmetric Membranes Formed by Blends of Block Copolymers, Maryam Radjabian, Volker Abetz
Advanced Materials 2015, 27, 352-355, (online 20 Nov.V 2014)
http://www.hzg.de/public_relations_media/news/058880/index.php.en - website HZG
http://dx.doi.org/10.1002/adma.201404309 -- Publication
Dr. Torsten Fischer | Helmholtz-Zentrum Geesthacht - Zentrum für Material- und Küstenforschung
New design improves performance of flexible wearable electronics
23.06.2017 | North Carolina State University
Plant inspiration could lead to flexible electronics
22.06.2017 | American Chemical Society
An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.
Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...
Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.
Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...
Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.
As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...
Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.
With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...
Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine
Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...
19.06.2017 | Event News
13.06.2017 | Event News
13.06.2017 | Event News
23.06.2017 | Physics and Astronomy
23.06.2017 | Physics and Astronomy
23.06.2017 | Information Technology