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| Hauptseite > Publikationsdatenbank > Straight rods, hold the twist: Rheology of dense suspensions of helices vs. rods |
| Hauptseite > Publikationsdatenbank > Straight rods, hold the twist: Rheology of dense suspensions of helices vs. rods |
| Conference Presentation (After Call) | FZJ-2026-03956 |
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2026
Abstract: The stiffness of dense packed rods depends on many factors such as the volume fraction ϕ, contour length L and persistence length l_p. The weight of each of these factors is difficult to determine as they are interconnected, L is often not known. Here we use re-polymerized flagella from bacteria to produce straight rods (l_p→∞) with fixed diameter d and variable L, as tuned by the use of initiators and detected by fluorescence microscopy. We polymerize the rods on the rheometer to produce an unperturbed sample before performing a frequency sweep. ϕ is chosen such that that ϕ L/d≫5.3 , which means that the rods are overpacked and intrinsically frustrated. We find a true plateau modulus, which scales as G_0^'∝L^3. When straining the sample we observe an immediate increase of the differential modulus K. This suggests that G_0^' is set by the number of encounters with other rods when a rotation is induced by shear, each of which will induce a bending of the test-rod.
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