| 研究実績の概要 |
We report a zwitterionic block copolymer composed of N-isopropylacrylamide and N,N-dimethyl-N-(3-(methacrylamido)propyl) ammoniopropane sulfonate monomers which self-assembles into different structures depending on the solution temperature. As the temperature is increased from 20 °C to 70 °C, the solubility of the polymer switches direction from insoluble to soluble to insoluble to soluble. During this process, the polymer self-assembly changes from polymersomes to micelles. These extraordinary transitions are possible because of the hydrophilic-hydrophobic ratio of the polymer blocks and the presence of a carbonyl group attached to the end of the poly(N-isopropyl acrylamide) chain. Additionally, one of these transitions can be controlled by the pH of the solution thanks to the protonation-deprotonation of the carbonyl and the charge neutralization of the ammonium moieties. The present work opens the possibility of designing polymers with temperature driven self-assembly properties that could be used for biomedical applications.
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