FIGURE 3.

Various pulling curves for multistrand connections. (A) Two molecules with the same pattern of sacrificial bonds but different free contour length of molecules. The molecules get loaded in parallel and the force is distributed between the two strands. Since molecule 1 is shorter than molecule 2, the sacrificial bonds on molecule 1 will be loaded to the bond-breaking force first. After the hidden length from the weakest sacrificial bond on molecule 1 is released, the second molecule has the shorter free contour length. Therefore the next bond that breaks is the weakest sacrificial bond on molecule 2. The total registered force curve is a superposition of these two curves. (B) Two molecules in parallel where one molecule has domains with sacrificial bonds and hidden length and the other molecule has no sacrificial bonds but acts as an exponential spring. The sacrificial bonds on molecule 1 will break in the order of their bond strengths. In the force curve, they will appear as small spikes on a larger slope. (C) Multiple molecules with different lengths bound between the surfaces with equal bond strengths. The length increase between neighboring molecules is constant. The molecules are loaded in parallel; the pulling force is distributed over all molecules. If the distributed force on one molecule exceeds the binding force or the breaking force of that molecule, that connection will break. Each molecule breaks at the same distributed force, but this force occurs at different pulling lengths. The pulling curve shows a steep increase and a successive drop of the following peaks where each peak is followed by a lower peak. (D) Same as panel C but with molecules where the length is not equally spaced. Depending on the length distribution of the molecules, a peak can be followed by either a lower peak or a higher peak.