Mechanics of Colloidal Membranes

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The goal of this project is to study the mechanics of colloidal membranes---membranes comprised of colloidal particles such as filamentous viruses or DNA origami bundles. These membranes have life-like abilities reminiscent of cell membranes, such as the ability to heal themselves or assemble spontaneously into complex and controllable shapes. Many of the technological advances of the twentieth century were made possible by discoveries in materials engineering. The development of corrosion-resistant stainless steel, synthetic polymers such as nylon, semiconductors and integrated circuits, and liquid crystals used in displays have all had a profound impact on society and our quality of life. Each of these advances required the theoretical framework and experimental techniques necessary to understand and control the material properties of inanimate matter. Today we are at the beginning of a new era of bio-inspired materials engineering, as it is now just becoming possible to create and control materials consisting of biological components and with the distinctive properties of living matter. The PIs will develop the theoretical and computational tools to predict and control the mechanics of colloidal membranes and how colloidal membrane shape depends on the experimental conditions. The research approach has the potential to bridge the physics, math and engineering communities. Educational YouTube videos related to the research will also be created for outreach to the public.Colloidal membranes are promising for their potential as highly reconfigurable microscopic structures, and as analogs to biological materials such as lipid bilayer membranes. While colloidal membranes share many properties with lipid bilayer membranes, such as their fluidity, they also have their own unique aspects, including a low energy cost for having edges. The study of the mechanics of these objects is still in its infancy, and requires a multidisciplinary approach including elements from solid mechanics, statistical mechanics, liquid crystal physics, and differential geometry. The research team will carry out three specific tasks: (i) calculate the entropy-driven or chirality-driven instability and subsequent nonlinear evolution of flat disk-shaped membranes to rippled helical sheets and twisted ribbons, (ii) calculate the force vs. extension relation for membrane disks and helicoidal ribbons, and (iii) predict and classify the shapes of colloidal membranes of more complex topology, such as catenoids and other observed structures with multiple holes.