Unified Understanding of Polymer Dynamics under Elongation and Shear

2021 Fiscal Year Final Research Report

• Project/Area Number: 19H02775
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 35020:Polymer materials-related
• Research Institution: Kyoto University
• Principal Investigator: Watanabe Hiroshi 京都大学, 化学研究所, 教授 (90167164)
• Co-Investigator(Kenkyū-buntansha): 松宮 由実 京都大学, 化学研究所, 准教授 (00378853)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: A型 Rouse 鎖 / 非平衡ダイナミクス / 摩擦低下 / 熱揺動力変化 / 非線形弾性効果 / 流動誘電緩和 / 流動拡散 / 非線形レオロジー

Outline of Final Research Achievements

For the standard molecular model for unentangled polymers, i.e., Rouse model, the equation of motion was fully analyzed for general cases of flow-dependent local friction z, spring stiffness k, and Brownian force intensity B, with z and B exhibiting tensorial nonlinearities. The dielectric loss e" reflecting the end-to-end fluctuation of the chain as well as the diffusivity under flow and rheological properties (viscosity and first normal stress difference coefficient) were analytically expressed in terms of z, k, and B to reveal characteristic features under flow, for example, lack of dielectric mode broadening under flow occurring in the velocity direction but acceleration of the relaxation in that direction. These analytical expressions enable experimental evaluation of z, k, and B, thereby serving as the very fundamental basis of molecular understanding of nonlinear flow behavior of polymers.

Free Research Field

ソフトマターの分子レオロジー

Academic Significance and Societal Importance of the Research Achievements

本研究は, 非絡み合い高分子の非線形レオロジー挙動の分子論的基盤を世界に先駆けて構築したものである。特に, 本研究が高分子鎖の摩擦係数, 弾性強度, 熱揺動力強度を実験的に評価することを可能とし, 高分子物理学に大きな進展をもたらしたことは, 学術的に大きな意義を持つ。さらに、本研究の成果は, 高分子樹脂の成形加工性を制御する基盤となり, 現在社会に不可欠の高分子産業にも大きく貢献する。