MechE Colloquium: Using drops to structure materials

My group aims at fabricating soft materials whose mechanical properties closely resemble those of natural counterparts. To achieve this goal, we are developing microfluidic processes to control the micrometer-length scale structure and local composition of soft materials.

Abstract:
Nature produces materials that exhibit exceptional mechanical properties. For example, the mussel byssus is a hydrogel-based tissue with a combination of strength and toughness that remains unmatched by manmade hydrogel-based counterparts. A clear difference between natural and manmade hydrogels is their structure: Natural hydrogels possess a well-defined, often hierarchical structure whereas manmade hydrogels are typically composed of randomly aligned polymers. These differences in structure might in parts be related to the different processing routes: While nature often uses drops to store reagents and release them at well-defined locations, we most frequently produce bio-mimetic materials by mixing reagents in bulk. Inspired by nature, my group is developing drop-based processes that offer superior control over the micrometer-scale structure of materials, thereby offering new possibilities to tune their mechanical properties. In my talk, I will present examples of the use of emulsion drops to produce capsules with thin shells and tuneable mechanical properties and their assembly into more macroscopic granular hydrogels with well-defined structures and adjustable mechanical properties.

Bio:
Esther Amstad studied material science at ETH in Zurich where she also carried out her Ph.D. thesis under the supervision of Marcus Textor (2010). As a Postdoctoral fellow, she joined the experimental soft condensed matter group of David A. Weitz at Harvard University (2011-2014) where she developed new microfluidic drop makers and used these drops to produce capsules with tunable permeability. Since June 2014, she heads the Soft Materials Laboratory (SMAL) at the institute of materials at EPFL as a tenure track assistant professor.