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:

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.
Polymers jump through hoops on pathway to sustainable materials
Recyclable plastics that contain ring-shaped polymers may be a key to developing sustainable synthetic materials.
Polymers to give early warning signs
Researchers at the University of Fribourg's Adolphe Merkle Institute (AMI) and Hokkaido University in Japan have developed a method to tailor the properties of stress-indicating molecules that can be integrated into polymers and signal damages or excessive mechanical loads with an optical signal.
The right polymers for the job
One of the most promising clean energy technologies just got even better.
More Polymers News and Polymers Current Events

Top Science Podcasts

We have hand picked the top science podcasts of 2019.
Now Playing: TED Radio Hour

Risk
Why do we revere risk-takers, even when their actions terrify us? Why are some better at taking risks than others? This hour, TED speakers explore the alluring, dangerous, and calculated sides of risk. Guests include professional rock climber Alex Honnold, economist Mariana Mazzucato, psychology researcher Kashfia Rahman, structural engineer and bridge designer Ian Firth, and risk intelligence expert Dylan Evans.
Now Playing: Science for the People

#540 Specialize? Or Generalize?
Ever been called a "jack of all trades, master of none"? The world loves to elevate specialists, people who drill deep into a single topic. Those people are great. But there's a place for generalists too, argues David Epstein. Jacks of all trades are often more successful than specialists. And he's got science to back it up. We talk with Epstein about his latest book, "Range: Why Generalists Triumph in a Specialized World".
Now Playing: Radiolab

Dolly Parton's America: Neon Moss
Today on Radiolab, we're bringing you the fourth episode of Jad's special series, Dolly Parton's America. In this episode, Jad goes back up the mountain to visit Dolly's actual Tennessee mountain home, where she tells stories about her first trips out of the holler. Back on the mountaintop, standing under the rain by the Little Pigeon River, the trip triggers memories of Jad's first visit to his father's childhood home, and opens the gateway to dizzying stories of music and migration. Support Radiolab today at Radiolab.org/donate.