Tuesday, May 29th: Topological defects in active nematics

Event Date: 

Tuesday, May 29, 2018 - 4:00pm

Event Location: 

  • KITP Main Seminar Room (1003 Kohn Hall)
  • Physics Colloquium

The laws of equilibrium statistical mechanics impose severe constraints on the properties of conventional materials assembled from inanimate building blocks. Consequently, such materials cannot exhibit autonomous motion or perform macroscopic work. Inspired by the remarkable properties of the biological cytoskeleton which is driven away from equilibrium by a conserved set of protein nanomachines, our goal is to develop soft active materials assembled from the bottom-up, using animate energy-consuming building blocks such as molecular motors and microtubule filaments. Released from the constraints of the equilibrium, these internally driven gels, liquid crystals and emulsions are able to change-shape, crawl, flow, swim, and exert forces on their boundaries to produce macroscopic work. We first describe structural and dynamical properties of 2D active nematic liquid crystals. In particular, we describe how circular confinements induce transition from a chaotic dynamics to coherent circularly flowing states. Subsequently, we describe methods to assemble 3D active nematic liquid crystals and our ongoing efforts to characterize both the structure and dynamics of the topological defects found in these materials. Our results illustrate how active matter can serve as a platform for testing theoretical models of non-equilibrium statistical mechanics, developing a new class of soft machines and potentially even shedding light on self-organization processes occurring in living cells.