Surveying the Free Energy Landscapes of Soft Matter Systems

在许多软物质系统中，最小自由能构型的稳定性和从一种状态到另一种状态的转变途径起着核心作用。液晶器件通常利用两种或两种以上（元）稳定状态的存在，并且由于仅在器件切换状态时才需要电源，因此具有很大的技术价值。在超疏水表面的许多应用中，一个主要的障碍是所谓的悬浮状态缺乏稳定性，即气体缓冲被困在表面波纹之间。脂质双分子层的形状转变在细胞运输以及细胞对外界刺激的反应中起着重要作用。在这些例子和许多其他例子中，关于系统自由能景观的详细信息是非常需要的，包括可能的最小能量配置，以及过渡态，能量势垒和不同局部最小值之间的过渡路径。因此，本项目的目的是开发一套数值技术和相应的软件，以调查连续介质软物质系统的自由能景观。潜在的应用包括，但不限于，湿润现象，液晶和膜的问题。事实上，所开发的技术将是通用的，允许不同的物理模型和复杂的边界条件实现和计算相对容易。

: In many soft matter systems the stability of minimum free energy configurations and the transition pathways from one state to another play a central role. Liquid crystal devices often exploit the existence of two or more (meta-)stable states and are of great technological interests because power is only needed when the devices switch states. A major obstacle in many applications of superhydrophobic surfaces is the lack of stability of the so-called suspended states, where gas cushions are trapped in between the surface corrugations. Shape transformations of lipid bilayers play an important role in cellular transport as well as how cells react to external stimuli. In these examples and many others, detailed information on the free energy landscapes of the systems is very desirable, including the possible minimum energy configurations, as well as the transition states, energy barriers, and transition pathways between different local minima. The aim of this project is thus to develop a set of numerical techniques, and correspondingly software, to survey free energy landscapes of continuum soft matter systems. Potential applications include, but are not limited to, problems in wetting phenomena, liquid crystals and membranes. In fact, the developed techniques will be versatile, allowing different physical models and complex boundary conditions to be implemented and calculated with relative ease.