単一ポリマーのダイナミクスは,安定したシーアフローで
D E Smith1, H P Babcock, S Chu
1Department of Physics, Varian Building, Stanford University, Stanford, CA 94305, USA.
Science (New York, N.Y.)
|March 12, 1999
まとめ
シーアフローの個々の柔軟なポリマーは転がりを見せますが,長方形のフローで見られる急激なコイル-ストレッチの移行ではありません. 変動率はワイセンベルグ数とともに増加し,複雑な動態を示しています.
科学分野:
- ポリマー物理学 ポリマー物理学
- 整形外科医 整形外科医 整形外科医
- ソフトマター物理学 ソフトマター物理学
背景:
- 流動中のポリマーの振る舞いを理解することは,材料科学と流体力学にとって極めて重要です.
- 以前の研究では,アンサンブル平均や異なるフロータイプに焦点を当てることが多く,個々のポリマーダイナミクスの洞察を制限していました.
研究 の 目的:
- 安定したシーアフロー下で個々の柔軟なポリマーの構成動態を直接観察し,定量化するために.
- 分子拡張,切断率,およびポリマーのリラックス時間との関係を調査する.
主な方法:
- ビデオ光顕微鏡を用いて,個々のポリマー鎖を直接観察した.
- 分子拡張を測定し,剪定速度の関数として確率分布を分析した (ガンマ;).
- 2つの異なるリラックス時間 (tau) を有する研究されたポリマー.
主要な成果:
- 末端から末端への分子転落を示す,大きな非周期的な時間変動が観察されました.
- 伸縮フローとは異なり,シーアフローでは急激なコイル・ストレッチ・トランジションが見つかりませんでした.
- 転落する変動の速度は,ワイセンベルク数 (gamma;tau) により増加した.
結論:
- 個々の柔軟なポリマーは,伸縮フローと比較してシーアフローで異なるダイナミックな行動を示します.
- 分子転落は,シアフローにおけるポリマー構成に影響を与える重要な要因です.
- ワイセンベルグ数は,この体制におけるポリマー転落の動態を効果的に特徴づけています.
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