Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Multifunctional coatings. Charged up and ready to connect

24.10.2013
An innovative strategy produces positively and negatively charged polymer chains ideal for generating multifunctional coatings

Gelatin, a well-known food ingredient, belongs to a class of molecules called polyampholytes that contain both positively and negatively charged components. When a polyampholyte is dissolved in liquid, this electronic structure imparts remarkable properties such as pH-dependent viscosity; it can also form a hydrogel.


Polymers formed from ionic precursors have an unusual chemical reactivity that could find application in antifouling coatings for ships.
© andrej67/iStock/Thinkstock

Now, Satyasankar Jana, Anbanandam Parthiban and co-workers from the A*STAR Institute of Chemical and Engineering Sciences in Singapore have developed a polyampholyte with multiple capabilities — including the ability to turn ordinary plastics into novel coating materials, thanks to unexpectedly strong interactions between the polymer’s charged sites1.

Mixing cationic and anionic salts known as ion pair comonomers (IPCs) is one of the best ways to synthesize polyampholytes. Most IPCs are made from unsaturated molecular ions with very similar chemical reactivity. This approach generates long, charge-neutral chains with application in fields such as chromatographic protein separation.

Jana, Parthiban and co-workers, however, implemented a different strategy. They investigated polymerization of IPCs with unequal chemical reactivity: a cationic nitrogen-bearing ring known as vinylimidazole and a styrenesulfonate. The intense positive charges within vinylimidazole-based polymers mean that these polymers are frequently employed as ion-conductive materials; the weaker styrenesulfonate anion, on the other hand, finds use in surfactants and polyelectrolytes.

The team suspected that these IPCs, which turn into mobile ionic liquids at high temperatures, could create polyampholytes with asymmetric charge properties and unusual molecular interactions never encountered before.

By using free radical reactions to construct the vinylimidazole-based polyampholytes, the researchers observed that their hunch was correct: the polymers assembled into chains with immobilized cationic and anionic units. In fact, the strong intermolecular forces in these polyampholytes rendered them insoluble in both organic and aqueous solvents. Switching to a more controlled chain-transfer polymerization method yielded asymmetric chains with improved solubility characteristics.

The team exploited the active charge properties of their polymers to turn lightweight poly(methyl methacrylate), or PMMA, plastics into ionically cross-linked materials. Mixing a small proportion of the asymmetric polyampholyte into PMMA formed a three-dimensional polymer network as the ionic sites reacted with one another and with the acrylic chains. The authors note that this kind of ionic cross-linking can have beneficial impacts on the stiffness and fracture behavior of PMMA, and opens the door to other applications.

The highly ionic nature of these polymers makes this approach useful for possible antifouling materials and layer-by-layer coating technology,” says Jana. “We are also trying to synthesize novel substances with this procedure, such as ionically cross-linked hydrogels.”

The A*STAR-affiliated researchers contributing to this research are from the Institute of Chemical and Engineering Sciences

Associated links
http://www.research.a-star.edu.sg/research/6783
Journal information
Jana, S., Vasantha, V. A., Stubbs, L. P., Parthiban, A. & Vancso, J. G. Vinylimidazole-based asymmetric ion pair comonomers: Synthesis, polymerization studies and formation of ionically crosslinked PMMA. Journal of Polymer Science Part A: Polymer Chemistry 51, 3260–3273 (2013)

A*STAR Research | Research asia research news
Further information:
http://www.research.a-star.edu.sg/research/6783
http://www.researchsea.com

More articles from Materials Sciences:

nachricht Argon is not the 'dope' for metallic hydrogen
24.03.2017 | Carnegie Institution for Science

nachricht Researchers make flexible glass for tiny medical devices
24.03.2017 | Brigham Young University

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Argon is not the 'dope' for metallic hydrogen

24.03.2017 | Materials Sciences

Astronomers find unexpected, dust-obscured star formation in distant galaxy

24.03.2017 | Physics and Astronomy

Gravitational wave kicks monster black hole out of galactic core

24.03.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>