"If you want a block copolymer that has a certain property, you pick the right phase for a given application of interest," explained Chris Bates, an assistant professor of materials in the UC Santa Barbara College of Engineering. "For the rubber in shoes, you want one phase; to make a membrane, you want a different one."
Only about five phases have been discovered in the simplest block copolymers. Finding a new phase is rare, but Bates and a team of other UC Santa Barbara researchers including professors Glenn Fredrickson (chemical engineering) and Craig Hawker (materials), Morgan Bates, staff scientist and assistant director for technology at the Dow Materials Institute at UCSB, and postdoctoral researcher Joshua Lequieu, have done just that.
Findings - Proceedings - National - Academy - Sciences
Their findings are published in the Proceedings of the National Academy of Sciences.
About 12 months ago, Morgan Bates was doing some experimental work on polymers she had synthesized in the lab, in an effort, she said, "to understand the fundamental parameters that govern self-assembly of block copolymers by examining what happens when you tweak block chemistry."
Possibilities - Chemistry - A - B - Blocks
There are endless possibilities for the chemistry of "A" and "B" blocks, according to Chris Bates. "Modern synthetic chemistry allows us to pick basically any type of A polymer and connect it with a different B block," he said. "Given this vast design space, the real challenge is figuring out the most crucial knobs to turn that control self-assembly."
Morgan Bates was trying to understand that relationship between chemistry and structure.
Parameter - Asymmetry - Blocks - Space - Process
"I had chemically tweaked a parameter related to what is called 'conformational asymmetry,' which describes how the two blocks fill space," she recalled of the process that led to the discovery. "We weren't necessarily trying to find a new phase but thought that maybe we'd uncover some new behavior. In this case, the A and B blocks that...
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