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 from Brightsurf:

Seeking the most effective polymers for personal protective equipment
Personal protective equipment, like face masks and gowns, is generally made of polymers.

Ultraheavy precision polymers
An environmentally friendly and sustainable synthesis of ''heavyweight'' polymers with very narrow molecular weight distributions is an important concept in modern polymer chemistry.

FSU researchers help develop sustainable polymers
Researchers at the FAMU-FSU College of Engineering have made new discoveries on the effects of temperature on sustainable polymers.

Structural colors from cellulose-based polymers
A surface displays structural colors when light is reflected by tiny, regular structural elements in a transparent material.

Growing polymers with different lengths
ETH researchers have developed a new method for producing polymers with different lengths.

Exciting new developments for polymers made from waste sulfur
Researchers at the University of Liverpool are making significant progress in the quest to develop new sulfur polymers that provide an environmentally friendly alternative to some traditional petrochemical based plastics.

Polymers can fine-tune attractions between suspended nanocubes
In new research published in EPJ E, researchers demonstrate a high level of control over a type of colloid in which the suspended particles take the form of hollow, nanoscale cubes.

Functional polymers to improve thermal stability of bioplastics
One of the key objectives for contemporary chemistry is to improve thermomechanical properties of polymers, in particular, thermostability of bioplastics.

Fluorescent technique brings aging polymers to light
Modern society relies on polymers, such as polypropylene or polyethylene plastic, for a wide range of applications, from food containers to automobile parts to medical devices.

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.

Read More: Polymers News and Polymers Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.