Dynamics of elastic surfactants

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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.