AsianScientist (Sep. 29, 2017) – By precisely controlling the order of polymer chains, scientists in Japan have opened up possibilities for synthesizing new materials. They published their method in the journal Nature Communications.
Manufactured polymers are ubiquitous in our 21st Century lives. The large molecules—long chains of smaller molecules bonded together, are used in the production of synthetic clothing, rubbers and glues and anything made of plastic.
However, the material properties exhibited by manmade polymers rely on the sequence order of individual molecules making up the polymer chain. Material scientists have thus far relied on mixing solutions together to form polymers. For example, a polymer chain made up of A, B, and C molecules could potentially take the form of A-B-C-B-A or A-C-A-B-B and so on. Each different polymer could possess vastly different properties, which may or may not be of use to society.
In this study, researchers from Hiroshima University developed a way to precisely define polymer-chain order, opening up the exciting potential of developing currently unimaginable materials. The researchers took their cue from nature, where structurally well-defined biopolymers are the norm.
For example, slight variations in DNA that change the order of a small number of organic molecules can give rise to the diverse spectrum of life. Hence, the scientists developed a self-sorting strategy that regulates the order that the molecules take when forming long chain polymers.
The new molecule-linking process can be imagined as three distinct railway wagons, each possessing two unique couplers at either end that only permit them to be hitched in a particular order. When the correct order is achieved, a train of unlimited length and complete regularity is possible.
Solutions made up of these new molecules, mixed in stages, formed couplet solutions. Molecule 1 bonded with molecule 2 to form a solution made up of 1-2 molecules. Molecule 2 bonded with molecule 3 forming a 2-3 solution, and molecule 3 bonded with molecule 1 to form a 3-1 solution.
When these 1-2, 2-3, and 3-1 couplet molecules were then mixed in solution, they self-sorted to form a long chain polymer in the form of (1-2-3-1-2-3)n. This represents a regular polymer sequence that is predetermined and self-sorting.
Professor Takeharu Haino of Hiroshima University pointed out that the resulting polymer is not simply a molecule, but a molecular complex—a supermolecule. This new supermolecule production method completely and accurately predicts the makeup of the end-product and can be manipulated and redesigned to give new manmade polymers with properties that could prove very useful for society.
The article can be found at: Hirao et al. (2017) Sequence-controlled Supramolecular Terpolymerization Directed by Specific Molecular Recognitions.
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Source: Hiroshima University; Photo: Shutterstock.
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