Page 54 - Plastics News July 2023

polymers are held together by weak- searchers led by Professor Shiki Yagai when the closed-ended ring-shaped
er, reversible hydrogen bonds. They from Chiba University aimed to com- seed was used, it did not elongate
can reversibly assemble and disas- pare and study the impact of these two itself, but rather served as a surface
semble, are highly versatile, and can processes while delineating the role of where new molecules could attach
be used for developing targeted drug precisely controllable "seeded supra- and form clusters, like a platform for
delivery therapies, sensors to detect molecular polymerization." Their goal new structures.
pollutants, diagnostic markers, energy was to figure out how different seed This research shows that the type of
storage devices, personal care prod- shapes affect the formation of new su- seed used in self-assembling supramo-
ucts, and self-repairing and recyclable pramolecular polymers; their findings lecular polymers influences the way
materials. Their excellent recyclabil- were first published on May 10, 2023, the molecules assemble, and the final
ity makes them wonderful candidate and subsequently appeared in Volume shape of the formed structures. This
molecules for sustainable applications; 59, Issue 48 of Chemical Communica- opens up exciting possibilities for vari-
however, there is one roadblock—re- tions on June 18, 2023. Prof. Yagaitells ous applications, from self-repairing
searchers have yet to understand how us what motivated the team to pursue and more easily recyclable materials
to control their polymer growth. this topic of research: "Because of the to more advanced drug delivery sys-
There have, however, been advance- difficulty in controlling polymeriza- tems, sensing technologies, and en-
ments in this aspect. Researchers tion, supramolecular polymers have ergy storage devices. As Prof. Yagai
are now able to build "unlikely" pol- not yet reached the point of practical states, "By understanding these as-
ymers by triggering their assembly application even though three decades sembly processes, we can design and
with "seeds," enabling control their have passed since their establishment develop the next generation of more
polymer growth. There are two main as a concept." He is convinced, how- precise and environmentally friendly
mechanisms through which this seed- ever, that because of their versatility, polymers with tailored structures and
induced self-assembly occurs: primary further research in this area is likely properties. The practical application
nucleation or elongation, where the to lead to widespread applications of of supramolecular polymers will en-
polymer grows from its end, and sec- these self-organizing polymers in our able us to produce plastic materials
ondary nucleation, where new mol- daily lives. with lower energy consumption and
ecules join the polymer by sticking to For their experiments, the research- reduce the energy required for recy-
its surface. The distinction between ers used two supramolecular poly- cling."
these processes is important because mers as "seeds." While a closed-ended The ability to manipulate these versa-
it enables researchers to better con- ring-shaped seed was used in a previ- tile, self-assembling polymers at the
trol and manipulate the growth of ous study, an open-ended, helicoidal molecular level offers great potential
these unique polymers. Unfortunate- seed was newly prepared. They found for addressing complex challenges
ly, in most cases of seeded self-assem- that when the open-ended, helicoidal and creating innovative, sustainable
bly, primary and secondary nucleation seed was used, it acted as a template solutions in fields ranging from health-
can be difficult to tell apart. for the target molecules to attach care to environmental sustainability.
and grow longer. On the other hand,
To tackle this issue, a group of re-

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54 PLASTICS NEWS July 2023