2025-10-06 北海道大学
DXB法の概略図。ナノ粒子を含む高分子材料に対してX線を照射し、時分割のＸ線回折像を取得した。その際に、ナノ粒子の自発的な回転によりX線回折強度が揺らぎ、その強度揺らぎに対して自己相関関数解析を用いることで、粒子の回転の速さを推定する。
＜関連情報＞
- https://www.hokudai.ac.jp/news/2025/10/x-2.html
- https://www.hokudai.ac.jp/news/pdf/251006_pr2.pdf
- https://pubs.acs.org/doi/10.1021/acs.nanolett.5c03840
時分割X線回折のゆらぎから明らかになった、ポリマー材料中のナノ粒子の回転ダイナミクス Fluctuation of Time-Resolved X-ray Diffraction Reveals the Rotational Dynamics of Nanoparticles in Polymer Materials
Tatsuya Arai,Masahiro Kuramochi,Kazuhiro Mio,Hiroshi Sekiguchi,Sakae Tsuda,Daisuke Sasaki,Tomoyasu Aizawa,and Yuji C. Sasaki
Nano Letters Published: September 14, 2025
DOI:https://doi.org/10.1021/acs.nanolett.5c03840
Abstract
Polymer nanocomposites, consisting of a polymer matrix and nanoparticles, are key materials in modern soft matter science. Because their macroscopic properties are closely linked to nanoscale dynamics, developing techniques to observe nanoparticle motion is essential. Here, we present novel methods to analyze the rotational dynamics of crystalline nanoparticles in various polymers using conventional time-resolved X-ray diffraction (TR-XRD). In the first approach, diffraction intensity fluctuations caused by nanoparticle rotation were analyzed via autocorrelation functions to extract relaxation times, defined as the duration for a diffraction spot to traverse a single pixel of the detector. The relaxation times varied significantly depending on the material’s rigidity and temperature. Second, two-time correlation analysis applied to TR-XRD data revealed time-dependent changes in nanoparticle dynamics during polymer phase transitions. These methods expand the utility of TR-XRD beyond structural analysis, offering a powerful tool to probe nanoscale rotational motion across a wide range of materials from liquids to solids.
