Shape controlled filaments suspensions – rheology and dynamics
Thomas Gibaud (ENS Lyon)
The mechanical behavior of a suspension of rigid and semiflexible filaments has been studied in great detail. In comparison the effect of the filament geometry has been relatively unexplored. Here, we hijack flagellar filaments from their original purpose in order to develop a versatile model rod-like bio-colloid whose shape and length can be tuned. We present experimental results on the rheological behavior of suspensions of (1) straight, (2) curly and (3) semi-straight/semi-curly flagella with an identical average contour length. We find that (1) and (2) show an elastic behavior at intermediate time but that (3) remains elastic and does not flow at long times. Using fluorescence microscopy, we track individual filament and find that this elastic plateau is related to a cage in which the filament is trapped for a certain among of time. Taken together, this highlights the role of filament geometry in suspension mechanics.