Researchers have recently developed a method for imaging polymerization catalysis reactions which will aid industry professionals in analyzing the molecular composition of synthetic polymers. By better understanding these polymers, researchers will be able to optimize them for future applications.
The method, dubbed CREATS (Coupled Reaction Approach Toward Super-resolution imaging) by the researchers, allows for single monomer resolution imaging of the polymerization catalysis reactions through fluorescent signaling. Published in Nature Chemistry, the technique provides researchers the ability to differentiate monomers from one another.
“Synthetic polymers are made of monomer units linked together like a string of beads,” said Peng Chen, Professor of Chemistry in the College of Arts and Sciences (A&S). While simple polymers contain identical monomers more complex polymers, called copolymers, contain an array of monomers. The precise arrangement of these monomers dictates various properties of the polymer such as elasticity. The sequence of monomers also plays a role in natural polymers such as protein, which is constructed of 20 amino acid monomers in a specific sequence.
“In a natural polymer, nature has control,” Chen said. “In synthetic polymers, humans are making the arrangements, and the chemists generally don’t have that precise control.” Sequencing copolymers has previously proven difficult to sequence due to their heterogeneity. Sequencing requires a methodology that can resolve individual monomers due to the differences in the length, composition, and even sequence of the individual chains.
Utilizing CREATS allows the researchers to identify every monomer as it is added to the polymer, allowing researchers to determine the sequence of a polymer as it is made. “Every monomer that goes in gives off a puff of light,” Chen said. “The light is induced by a laser, and the puff of light has a color. In our case, it’s either green or yellow. By seeing whether it’s yellow or green, we see what monomer goes in.”
By combining existing methods to measure polymer properties with the new method of identifying the sequence and structure, the researchers can correlate the structure and function of a polymer. “If you know how sequence controls property, you can really think about designing whatever sequence you want to achieve a certain property,” Chen said. “This knowledge presumably can help people tailor their materials for a desired application.”