Dresden 2020 – wissenschaftliches Programm
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CPP 95.4: Hauptvortrag
Donnerstag, 19. März 2020, 15:45–16:15, ZEU 222
Active Polymeric Liquid Crystals Under Confinement — •Juan de Pablo — University of Chicago, Chicago, USA
Polymeric materials that comprise mechano-chemically active components are able to undergo spontaneous structural rearrangements that generate internal stresses and motion. These stresses can be particularly large in the case of liquid crystalline polymers, where elasticity becomes important. When confined, at intermediate to high concentrations such materials form nematic phases that are riddled with defects that serve as attractors for solutes or colloidal particles, and can be used for directed transport. Going beyond passive nematic systems, introducing internal activity in the form of molecular motors leads to the emergence of new structural and dynamical features that are not found in materials at rest. This lecture will focus on the relationship between structure, activity, and motion in confined lyotropic liquid crystalline polymeric systems that include colloidal particles. More specifically, results will be presented for actin and tubulin suspensions, where activity is generated by kinesin or myosin motors. A distinctive feature of these biopolymers is that characteristic contour lengths can range from hundreds of nanometers to tens of microns, thereby making them amenable for study by optical microscopy. By relying on molecular and meso-scale models, it is possible to arrive at a comprehensive description of these suspensions that helps explain the connections between molecular structure, the formation and shape of distinct topological defects, the localization of particles in such defects, activity, and defect dynamics.