Publication Report, 12 August 2023

We have discovered a new type microphase separation system of double hydrophilic block copolymers driven by cononsolvency.

We are investigating the microphase separation of double hydrophilic block copolymer aqueous solutions as a novel nano-meter scale molecular compartment which is produced on demand through the molecular interaction control. Double hydrophilic diblock copolymers comprising a cononsolvency active poly(carboxybetaine methacrylate) (PCB2) and inactive poly(2-ethyl-2-oxazoline) (PEtOx) (PEtOx-b-PCB2) dissolved in water and ethanol but aggregated in their mixtures with a specific ethanol volume fraction (fEtOH) range owing to the cononsolvency of PCB2 chains. PEtOx-b-PCB2 produced well-ordered mesoscopic lattice structures in water–ethanol mixed solvents, and their morphologies and lattice distortion depended on the fEtOH and the polymer concentration. The controlled microphase separation, morphology transition, and collapse of biocompatible mesophases can pave the way for the design of stimuli-responsive molecular compartments.

Takumi Masuda was mainly in charge of this project. He is a brilliant student who has achieved the highest grades in our department. His outstanding concentration and continuous effort on research have led him to success of many projects. He takes good care of his juniors, friends, and also me, so is trusted by those around him. It is my pleasure to be able to work with him.

Mai Nakamura was the first student to tackle on this project and found out the cononsolvency-induced phase separation. We are convinced that this discovery and research results would not have been possible without her hard work and intelligence. I sincerely wish her the best.

This is the third publication for Masaya. We thank him for his accomplishments as a laboratory startup member. Well done!!

This is the first publication on Macromolecules, a journal of American Chemical Society specific in macromolecular science discipline, from the Higaki Lab, and I’m proud of all the students involved in the project.