Challenge to enhance the mechanical property of polymeric materials by introducing bio-inspired folding structure

Research Project

Project/Area Number	18K19105
Research Category	Grant-in-Aid for Challenging Research (Exploratory)
Allocation Type	Multi-year Fund
Review Section	Medium-sized Section 35:Polymers, organic materials, and related fields
Research Institution	The University of Tokyo
Principal Investigator	Yoshie Naoko 東京大学, 生産技術研究所, 教授 (20224678)
Project Period (FY)	2018-06-29 – 2021-03-31
Project Status	Completed (Fiscal Year 2020)
Budget Amount *help	¥6,500,000 (Direct Cost: ¥5,000,000、Indirect Cost: ¥1,500,000) Fiscal Year 2020: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000) Fiscal Year 2019: ¥2,210,000 (Direct Cost: ¥1,700,000、Indirect Cost: ¥510,000) Fiscal Year 2018: ¥2,210,000 (Direct Cost: ¥1,700,000、Indirect Cost: ¥510,000)
Keywords	高分子材料物性 / 生体模倣 / 強靭化 / 動的結合 / 架橋ポリマー / 分子内架橋 / 機械特性 / 筋肉
Outline of Final Research Achievements	Muscle proteins have intramolecular folding structure driven by transient hydrogen bonds. The folded structure is unfolded upon external stress, efficiently dissipating energy to avoid fracture of the molecule. Inspired by this mechanism in nature, we aimed to develop a general methodology for toughening of artificial polymeric materials based on intramolecular folding structure. We introduced strong hydrogen-bonding groups into a block copolymer-type thermoplastic elastomer to induce intramolecular crosslinking. The mechanical properties of the polymers with intramolecular folding structure were examined by uniaxial tensile tests, which revealed the enhancement effect of intramolecular folding on mechanical performance of crosslinked polymers. We expect that the concept of intramolecular folding developed here will serve as a basis for enhancing mechanical functionalities of various polymeric materials.
Academic Significance and Societal Importance of the Research Achievements	本研究により、分子内折りたたみ構造の導入が、高分子材料の新たな力学特性向上手段となり得ることを示す先駆的な知見が得られた。高分子の三次元網目からなる架橋高分子は産業上重要な材料であり、その力学的信頼性の向上は常に重要な課題である。今後、より多様な高分子種・結合種を用いた折りたたみ構造を実現・検証することで、優れた力学機能を有する材料の開発につながると期待される。