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Simulation of nucleation dynamics at the lamellar-cylinder transition in diblock copolymer melts.

机译:模拟二嵌段共聚物熔体中层状-圆柱状转变的成核动力学。

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摘要

We simulate the time-dependent Landau-Brazovskii equation in three dimensions, focusing on the kinetics of the nucleation mechanism of the lamellar-cylinder transition in a diblock copolymer melt. The underlying microstructure leads to a complicated droplet interface structure, an orientation-dependent interfacial velocity and non-spherical nuclei. In part, our motivation is to show that our simulation method is a viable way of studying nucleation. We compare our phase diagram with predictions by Wickham et al. J. Chem. Phys (2003), finding good agreement, supporting the use of a single mode approximation for the density field at weak segregation. We find critical droplets which compare well with the theory near coexistence but the theory breaks down for small droplets. Our growing droplets adopt a lens-shape with a major axis normal to lamella. The aspect ratio is better described by a ratio of growth velocities than equilibrium theory. We go beyond the static theory to find orientation-dependent interfacial velocities which are constant for large droplets and depend linearly on quench depth in the nucleation regime.
机译:我们在三个维度上模拟了时间相关的Landau-Brazovskii方程,重点研究了二嵌段共聚物熔体中层状-圆柱体转变成核机理的动力学。底层的微观结构导致复杂的液滴界面结构,与方向有关的界面速度和非球形核。我们的动机部分是为了证明我们的仿真方法是研究成核的可行方法。我们将相位图与Wickham等人的预测进行了比较。 J.化学Phys(2003),找到了很好的一致性,支持在弱偏析下对密度场使用单模近似。我们发现临界液滴可以与近乎共存的理论相比较,但是对于微小的液滴,该理论会崩溃。我们生长的液滴采用长轴垂直于薄片的透镜形状。与平衡理论相比,用生长速度的比率更好地描述了纵横比。我们超越了静态理论,找到了与取向有关的界面速度,该界面速度对于大液滴而言是恒定的,并且在成核机制中线性依赖于淬火深度。

著录项

  • 作者

    Spencer, Russell.;

  • 作者单位

    University of Guelph (Canada).;

  • 授予单位 University of Guelph (Canada).;
  • 学科 Chemistry Physical.;Computer Science.;Physics Condensed Matter.
  • 学位 M.Sc.
  • 年度 2011
  • 页码 65 p.
  • 总页数 65
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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