Nav: Home

Catalyst switching means four become one

November 07, 2019

By juggling four different chemical reactions in a single flask, researchers at KAUST have combined four polymers to form a single multicrystalline substance. Materials that seamlessly combine multiple polymers potentially merge the best aspects of each material.

The versatile new approach for creating these "multicrystalline multiblock polymers," developed by Nikos Hadjichristidis from the KAUST Catalysis Center and his team, in collaboration with Yves Gnanou, could lead to a whole new family of advanced polymer materials.

Polymers are long chain molecules made by connecting together small molecule "monomeric units," like a string of identical beads on a necklace. Recently, researchers have developed ways to make "double-crystalline" copolymers in which one part of the chain is made from one kind of monomer and the other part is made from another. "Double-crystalline block copolymers have myriad applications, such as for energy storage, tissue engineering and drug delivery," says Viko Ladelta, a member of Hadjichristidis's team.

Adding an even greater number of different polymer sections has the potential to produce materials with even more advanced properties. "But the synthetic procedures are very demanding," Ladelta explains. "It was difficult to perform even the synthesis of double-crystalline block copolymers, due to the incompatibility of the monomers and catalysts." Making materials that incorporate four different monomers in four chemically different blocks-- tetra-crystalline tetrablock quarterpolymers--leads to even greater incompatibility.

Hadjichristidis and his team have developed a trick, called catalyst switching, to help overcome the incompatibility problem. Most organic catalysts that are used for a polymer-forming reaction, called ring-opening polymerization, are either acids or bases. By adding one type of monomer to the polymer chain under basic conditions, then adjusting the pH and using a second catalyst to add the next monomer, it is possible to create multiblock polymers in a single reaction pot. "This strategy saves time and also avoids the risk of any contamination of the polymer," Ladelta says.

Hadjichristidis's group have previously used catalyst switching between organic catalysts to create double-crystalline and triple-crystalline polymers. Now, for the first time, the team has shown it is possible to adjust the pH, then switch from an organic to a metal catalyst, to make a tetracrystalline tetrablock quarterpolymer.

"Our plan is to expand the scope of the catalyst switch strategy to other types of polymerization," Ladelta says. "We will synthesize more complex multicrystalline polymers and collaborate with polymer physicists to understand the physical properties to guide us toward real-world applications."
-end-


King Abdullah University of Science & Technology (KAUST)

Related Polymers Articles:

Polymers to the rescue! Saving cells from damaging ice
Research published in the Journal of the American Chemical Society by University of Utah chemists Pavithra Naullage and Valeria Molinero provides the foundation to design efficient polymers that can prevent the growth of ice that damages cells.
Mixing the unmixable -- a novel approach for efficiently fusing different polymers
Cross-linked polymers are structures where large molecular chains are linked together, allowing exceptional mechanical properties and chemical resistance to the final product.
Theoretical tubulanes inspire ultrahard polymers
Rice University engineers print 3D blocks based on theoretical tubulanes and find they're nearly as hard as diamond.
New synthesis method yields degradable polymers
MIT chemists have come up with a way to make certain drug-delivery polymers more readily degradable by adding a novel type of building block to the polymer backbone.
Bottom-up synthesis of crystalline 2D polymers
Scientists at TU Dresden and Ulm University have succeeded in synthesizing sheet-like 2D polymers by a bottom-up process for the first time.
Secret messages hidden in light-sensitive polymers
Scientists from the CNRS and Aix-Marseille Université have recently shown how valuable light-sensitive macromolecules are: when exposed to the right wavelength of light, they can be transformed so as to change, erase or decode the molecular message that they contain.
Successful application of machine learning in the discovery of new polymers
As a powerful example of how artificial intelligence (AI) can accelerate the discovery of new materials, scientists in Japan have designed and verified polymers with high thermal conductivity -- a property that would be the key to heat management, for example, in the fifth-generation (5G) mobile communication technologies.
How to capture waste heat energy with improved polymers
By one official estimate, American manufacturing, transportation, residential and commercial consumers use only about 40 percent of the energy they draw on, wasting 60 percent.
Researchers can now predict properties of disordered polymers
Thanks to a team of researchers from the University of Illinois at Urbana-Champaign and the University of Massachusetts Amherst, scientists are able to read patterns on long chains of molecules to understand and predict behavior of disordered strands of proteins and polymers.
Synthesis of helical ladder polymers
Researchers at Kanazawa University synthesized helical ladder polymers with a well-defined cyclic repeating unit and one-handed helical geometry, as they reported in the Journal of the American Chemical Society.
More Polymers News and Polymers Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Teaching For Better Humans 2.0
More than test scores or good grades–what do kids need for the future? This hour, TED speakers explore how to help children grow into better humans, both during and after this time of crisis. Guests include educators Richard Culatta and Liz Kleinrock, psychologist Thomas Curran, and writer Jacqueline Woodson.
Now Playing: Science for the People

#556 The Power of Friendship
It's 2020 and times are tough. Maybe some of us are learning about social distancing the hard way. Maybe we just are all a little anxious. No matter what, we could probably use a friend. But what is a friend, exactly? And why do we need them so much? This week host Bethany Brookshire speaks with Lydia Denworth, author of the new book "Friendship: The Evolution, Biology, and Extraordinary Power of Life's Fundamental Bond". This episode is hosted by Bethany Brookshire, science writer from Science News.
Now Playing: Radiolab

Space
One of the most consistent questions we get at the show is from parents who want to know which episodes are kid-friendly and which aren't. So today, we're releasing a separate feed, Radiolab for Kids. To kick it off, we're rerunning an all-time favorite episode: Space. In the 60's, space exploration was an American obsession. This hour, we chart the path from romance to increasing cynicism. We begin with Ann Druyan, widow of Carl Sagan, with a story about the Voyager expedition, true love, and a golden record that travels through space. And astrophysicist Neil de Grasse Tyson explains the Coepernican Principle, and just how insignificant we are. Support Radiolab today at Radiolab.org/donate.