Tuning Synthetic Semiflexible Networks by Bending Stiffness

Abstract

The mechanics of complex soft matter often cannot be understood in the classical physical frame of flexible polymers or rigid rods. The underlying constituents are semiflexible polymers, whose finite bending stiffness ($\kappa$) leads to non-trivial mechanical responses. A natural model for such polymers is the protein actin. Experimental studies of actin networks, however, are limited since the persistence length ($l_{\text{p}}\propto \kappa$) cannot be tuned. Here, we experimentally characterize this parameter for the first time in entangled networks formed by synthetically produced, structurally tunable DNA nanotubes. This material enabled the validation of characteristics inherent to semiflexible polymers and networks thereof, i.e., persistence length, inextensibility, reptation and mesh size scaling. While the scaling of the elastic plateau modulus with concentration $G_0\propto c^{7/5}$ is consistent with previous measurements and established theories, the emerging persistence length scaling $G_0\propto l_{\text{p}}$ opposes predominant theoretical predictions.

arXiv comment5 pages, 4 figures, + Supplemental Information

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Cited by in corpus (5)

• Biopolymers: life's mechanical scaffolds
• Synergistic interactions between DNA and actin trigger emergent viscoelastic behavior
• The Role of Stickiness in the Rheology of Semiflexible Polymers
• Persistence length and plateau modulus of semiflexible entangled polymers in primitive chain network simulations
• Measuring structural parameters of crosslinked and entangled semiflexible polymer networks with single-filament tracing