在三维剪切的叶片半相中,结构和质之间的关系
1Department of Chemical Engineering, Indian Institute of Science, Bangalore 560 012, India. kumaran@iisc.ac.in.
Soft matter
|July 4, 2023
概括
模拟显示了剪切流如何影响层状半相形成. 材料特性和剪速控制结构,缺陷形成和粘度,指导质行为量身定制.
科学领域:
- 材料科学 材料科学 材料科学
- 计算化学计算化学
- 类风病学 类风病学 类风病学
背景情况:
- 对材料科学来说,了解两性分子的自我组装到有序结构,如状半相,至关重要.
- 切割流是一种常见的加工条件,它对软材料的结构和性能产生重大影响.
- 之前的研究已经探讨了剪切效应,但需要对不同流量条件下的进化动态进行详细的基于模拟的洞察.
研究的目的:
- 通过使用 mesoscale 模拟,研究从剪切流下的无序状态到层状半相的演化.
- 阐明材料参数,切割速率,以及由此产生的结构排序和质性质之间的关系.
- 为定制材料特性和流量条件提供指导,以实现所需的质行为.
主要方法:
- 介面尺度模拟使用度场 (ψ) 模型来区分水友和疏水成分.
- 使用兰道-金兹堡自由能量函数,加上对正弦调制 (波长λ) 的术语.
- 解决基于模型H方程的动态方程,以分析结构和学.
主要成果:
- 扩散时间 (λ2/D) 和逆应变速率 (γ̇−1) 之间的相互作用决定了结构进化和学.
- 在低的埃里克森数下,有缺陷的有序层形成,导致由于高层刚度而增加粘度.
- 在高的埃里克森数下,剪切变形先于层形成,导致层层无序,粘度过低.
结论:
- 这项研究表明,剪切流可以诱导状半相位形成,由此产生的结构和质是可调的.
- 缺陷形成和剪切下的动态是影响粘度的关键因素.
- 这些发现为通过明智地选择材料参数和剪切条件来控制材料自组装和质性质提供了实际见解.
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