Construction of Artificial Higher-Order Structure of Crystalline Polymer Utilizing Non-Equilibrium Property

2021 Fiscal Year Final Research Report

• Project/Area Number: 17K05993
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Polymer/Textile materials
• Research Institution: Kyoto University
• Principal Investigator: Nishida Koji 京都大学, 工学研究科, 准教授 (80189290)
• Project Period (FY): 2017-04-01 – 2022-03-31
• Keywords: 結晶性高分子 / リングライト / ダークリング / 融点の逆転 / ギブズ-トムソン効果 / 非平衡性

Outline of Final Research Achievements

Polymer crystallite having ring-like morphology was obtained which termed “ring-lite” here. The ring-lite consists of the concentrically arranged crystalline and molten regions of a single-component polymer. The ring-lite is one of the consequences of the Gibbs-Thomson effect. On the other hand, a molten ring structure was also obtained. The latter structure was termed “dark-ring”, because it appears like a black circle when observed by polarizing microscope. Contrary to the appearance of ring-lite due to “normal” Gibbs-Thomson effect, the dark-ring was obtained by the inversion of the melting point when a specific heating rate was applied.
The ring-lite and dark-ring have a structure in which the crystalline region and the molten region are reversed. These “artificial” higher order structures of crystalline polymer were obtained by utilizing a non-equilibrium property of the polymeric material.

Free Research Field

高分子構造，高分子物性

Academic Significance and Societal Importance of the Research Achievements

リングライトの形成は，ギブズ-トムソン効果の可視化という意義を有する．純物質の融点は不変と考えられがちであるが，ギブズ-トムソン効果を効果的に利用することで，結晶性高分子の融点が制御可能であるということをリングライト形成の可視化により示せたことになる．
また，融点の反転現象の可視化は，本来低融点であるはずの領域が高融点化するという特異な現象であり，工業的には結晶性高分子材料の耐熱化への応用も期待される．
リングライトとダークリングは，学術雑誌の表紙を飾るほど，“美しい”構造であり，サイエンスの成果が専門外の方への啓蒙につながれば幸いである．