Yuji Higaki,* Masaya Takahashi, Takumi Masuda
"Phase Behavior of Double Zwitterionic Block Copolymers in Water: Morphology Transition through Concentration Dependent Selectivity of Water Partitioning"
Macromolecular Chemistry and Physics, in press DOI: 10.1002/macp.202200416
“What is the phase diagram of double zwitterionic block copolymers composed of a poly(carboxybetaine) and a poly(sulfobetaine)?”
This is the first paper mapping out phase diagrams of novel double zwitterionic diblock copolymers composed of a poly(carboxybetaine methacrylate) (PCB2) chain and a poly(sulfobetaine methacrylate) (PSB4) chain (PCB2n-b-PSB4m) in water. Phase diagrams were constructed with polymer concentration, f, and PSB4 volume fraction at 25°C. PCB2n-b-PSB4m aqueous solutions showed symmetric phase diagram above f = 0.55, indicating the water is nearly neutral to PCB2 and PSB4. The morphology transformed from the PCB2 columnar to lamellar to PSB4 columnar with decreasing f and the phase boundary exhibited a negative slope below f = 0.45. The lyotropic mesophase of double zwitterionic block copolymers is a unique molecular system that may be useful for biomedical applications where compartments for hydrophilic molecules are required.
Masaya Takahashi was in charge of this project. He systematically synthesized numerous block copolymers and mastered the technique of analyzing the phase separation of block copolymers by SAXS measurements, leading to the success of this project. Although he appears quiet and lazy at times, he can continue to work hard, actually, he has succeeded in obtaining a powerful body through continuous muscle training. It was my pleasure to have an adventure with him to unravel the nature of double zwitterionic block copolymers. I believe in his bright future at work and private life. Takumi Masuda has made a big contribution to data analysis and validation to complete this project. I appreciate his support and look forward to his further growth.
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