Figure 8.
Nonlinear stiffening in prestress measurements. (A) Filamin networks with RF = 0.003 and L = 1 (squares), 5 (triangles), 15 μm (solid circles); RF = 0.005 with L = 15 μm (diamonds); and RF = 0.01 with L = 15 μm (open circles, bundled network). K′ is independent of prestress, σo, for small prestresses before beginning to increase with σo at a critical stress, σc. Networks with higher RF and L stiffen more and support larger stresses before breaking. (Line) Linear scaling predicted by the model. (B) Rigidly cross-linked network with L = 15 μm and RB = 0.0003 (diamonds), 0.001 (inverted triangles), 0.003 (triangles), 0.03 (circles), and 0.3 (squares). These networks also display stiffening behavior, but the maximum stiffness and stress are roughly the same for every sample. (Line) The σo3/2 scaling predicted by the affine thermal model.