The size of an aggregate, N agg , was defined the number of chains that it contained. Fig. shows the growth over time t of the average aggregate size, ⟨N agg (t)⟩, in each solvent. For 20mers in the poor and intermediate solvents, aggregation initially occurred rapidly, with the average aggregate size approaching three chains in the intermediate, and four chains in the poor solvent, after 3 µs. In the better ("good") solvent, aggregation occurred much slower, with the average aggregate size remaining under 2 chains, indicating the presence of many unaggregated chains. The time dependence appears to be roughly independent of chain length at the same φ V N 1/2 (see ESI Fig. ), but shows a strong dependence on concentration, which will be discussed further in Section 3.3.