Dynamics of elastic surfactants

漂浮在液体表面的薄而柔韧的物体的自然例子包括树叶、纤维和昆虫。该奖项旨在了解这些柔性细丝和薄片附着在液体界面上的过程。除了推进这些无处不在的自然过程背后的基础物理学之外，这种理解将为使用薄片和细丝作为表面屏障来分离两种液体奠定基础。虽然这种表面活性剂的功能传统上是通过部署适当的分子或纳米颗粒来实现的，但使用薄片来包裹和保护液体货物，或将有毒液滴与周围环境隔离开来，具有显著的优势。将为初中和高中科学教师组织一个关于流体和柔性弹性材料的图案形成的年度讲习班，该专题与本奖项的主题密切相关。这是一项结合实验和理论的研究，旨在探索高柔性固体片在流体-流体界面上的吸附动力学。提出的研究研究弹性毛细现象的新的动力学方面，即弹性片或长丝在粘性界面上的吸附动力学。解决与这一基本动力学步骤相关的谜题暴露了柔性元素界面动力学中的一些基本问题。先前对流体-结构相互作用的研究主要集中在剪切力和毛细力通过柔性元件内的弯矩来平衡的情况下，该奖项将解决高度可弯曲物体的重要但尚未探索的情况，其中流体产生的力自然比弯曲刚度大得多。研究生和本科生都将参与研究，并有机会接触到理论和实验成果。此外，还将通过组织有针对性的暑期学校，对研究生和本科生进行相关科学主题的培训。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Natural examples of thin, flexible objects floating at the surface of a fluid include leaves, fibers, and insects. This award seeks to understand the phenomena surrounding the process of attachment of these flexible filaments and sheets to the liquid interface. Apart from advancing the fundamental physics behind these ubiquitous natural processes, this understanding will lay a foundation for the use of sheets and filaments as surface barriers that allow the separation of two liquids. While this surfactant function is traditionally achieved in technological processes by deploying appropriate molecules or nanoparticles, using sheets to wrap and protect a liquid cargo, or sequester a toxic droplet from its surroundings, offers significant advantages. An annual workshop on pattern formation in fluids and flexible elastic materials, a topic closely aligned with the themes of this award, will be organized for middle- and high-school science teachers.This is a joint experimental and theoretical research to explore dynamics of the adsorption of highly flexible solid sheets at fluid-fluid interfaces. The proposed research study novel dynamical aspects of elasto-capillary phenomena on the dynamics associated with the adsorption of an elastic sheet or filament to a viscous interface. Addressing the puzzles associated with this essential kinetic step lay bare some fundamental issues in interfacial dynamics of flexible elements. While previous studies of fluid-structure interaction have focused on regimes where shear and capillary forces are balanced by bending moments within a flexible element, this award will address the important, but unexplored regime of highly bendable objects where fluid-generated forces are naturally much larger than the bending rigidity. Both graduate and undergraduate students will participate in the research and have the benefit of exposure to theoretical and experimental efforts. In addition, outreach efforts to train both graduate and undergraduate students in the associated science topics will be conducted by organizing targeted summer schools.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.