Ultraslow relaxation and hidden phase transition behavior of ultrathin glassy polymers.

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K05617
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Biological physics/Chemical physics/Soft matter physics
• Research Institution: Kwansei Gakuin University
• Principal Investigator: Takahashi Isao 関西学院大学, 理工学部, 教授 (10212010)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 高分子 / 薄膜 / ガラス転移 / 緩和現象 / シンクロトロン放射光

Outline of Final Research Achievements

For glass-forming polymers, surface morphology and thickness were precisely measured with surface-sensitive X-ray scattering techniques so as to detect phase transition behavior emerged on glass transition of ultrathin films. For semicrystalline polymers, details on crystallization of thin polymers from glassy state, e.g., surface morphology, crystallinity and surface/interface-induced preferred orientation were characterized at synchrotron radiation facility. Information obtained by X-ray are combined with that by atomic force microscopy so as to clarify some of the unsolved problems including slow relaxation peculiar to thin glassy layers. Followings are intensively studied: (1) Phase transition expected to be hidden beneath glass transition; (2) Relaxation in thickness of glass layers that is very different from relaxation in volume of glassy materials; (3) Novel ultrathin crystal engineering platform based on glassy thin films.

Free Research Field

ソフトマターの表面・薄膜構造

Academic Significance and Societal Importance of the Research Achievements

研究成果の概要に記した項目（１）については今回の研究期間内に試料表面における電子密度関数の相関の温度変化についてのデータを得ることが出来たわけであるが、これは長年にわたり議論されてきたガラス転移の本質を理解するための一助となるものと期待される。（２）については分子間相互作用などが異なるタイプの高分子に調査対象を広げて緩和測定を行うことで、ガラスに対する、特に薄膜ガラスに対する我々の見解を部分的に改めざるを得ないと考えさせられるレベルの知見を得た。（３）についてはガラス化した薄膜の結晶化技術に大きな進展が見られ、長年未解明であったソフトマター結晶の構造解析に成功したということを記しておきたい。