Physicists Narayanan Menon, Benny Davidovitch and Christopher Santangelo, with polymer scientist Thomas Russell, recently won a three-year, $1 million Keck Foundation grant to develop the basic science needed to spontaneously deliver ultrathin films to fluid interfaces. The W.M. Keck Science and Engineering program funds “endeavors that are distinctive and novel in their approach. It encourages projects that are high-risk with the potential for transformative impact.”
As Menon explains, he and his collaborators will build upon their previous successes to tackle a handful of new problems, each more difficult than the last. The researchers are particularly interested in creating films that start out crumpled but can instantly expand to create a super thin barrier between two materials when deployed. For example, “imagine throwing a crumpled ball at a wall and when it hits, the ball instantly unfurls and paints the wall with a barrier sheet 10,000 times thinner than paper,” Menon says. “We have preliminary experiments that indicate the feasibility of this approach, but we need many further experiments and theoretical work to understand and control how such a film spontaneously and explosively unfurls when it is placed between two liquids.”
The research will integrate the skills of the four investigators: Menon’s lab studies the behavior of a variety of soft materials, Russell is a recognized expert on interfacial materials and assembly, and Davidovitch and Santangelo are theorists with a background in the role of geometry and mechanics in the formation of patterns. They will use high-speed microscopy, quantitative image analysis, advanced materials synthesis,computer simulation and theoretical analysis to harness a range of applications.
Menon notes that he and colleagues face several scientific challenges including the dynamics of uncrumpling, interactions between crumpled objects dispersed in a fluid, elasticity of heterogeneous and anisotropic films, and the mechanics of an interface laden with a mosaic of elastic sheets. But resulting new “solid surfactants” could be used to bandage leaks or cracks, impart chemical function or isolation to an interface, provide mechanical rigidity to a fluid surface or shrink-wrap drops.
“It’s a big challenge that we see as made up of many intermediate hurdles before we arrive at a self-deploying interfacial material,” Menon points out. Practical applications might include sequestering an oil spill, for example, or biomedical applications such as drug delivery.
Much of the grant money will be used to hire graduate students and postdoctoral researchers who will conduct experiments over the next three years. The last Keck award made to UMass Amherst was over a decade ago, Menon notes, and helped seed the nanoscience effort on campus. “We hope that this Keck award similarly contributes to building a vibrant community of scientists here, applying sheets as surface-active materials.”
Image: UMass Amherst researchers say the major enabling insight is that a sheet, initially crumpled while suspended in one fluid, spontaneously and explosively unfurls at the surface of the fluid, acting as a surfactant between two immiscible fluids.To advance this approach, several scientific challenges must be tackled, including the dynamics of uncrumpling.