Arguably the most significant assumption in the theory is that aggregation only occurs between two single chains to give an aggregate of size two. This is not the case for the simulations studied in this work, in which many aggregates form containing more than two chains (see Fig. ). In addition, the definition of τ c as the time taken for the concentration of single chains to fall to 25% of the original concentration, although consistent with the notion that the aggregation time scale should correspond to when most chains are in aggregates, is somewhat arbitrary. However, according to the theory in ESI Section S9, the specific choice of this proportion (x) of single chains used to define τ c is not expected to affect the scaling of c † with N, although c † at a given N is predicted to scale with (x -1 -1).