The predicted values of c † (including hydrodynamic interactions) under conditions corresponding to those used in the work of ref. 10 (30mers, c ≈ 5 g/L) and ref. 12 (180mers, c < 1 g/L) can help explain the contrasting observations in these studies. For such as those used in ref. 10 for which extended rod-like aggregates were observed, the critical concentration is predicted to be approximately 1 g/L, well below the concentrations used in the experiments. At concentrations of 5 g/L (roughly corresponding to the concentrations used in the simulations conducted in this work) multi-chain aggregation is therefore expected to dominate single-chain collapse, giving rise to the observed rod-like aggregates. The effect of concentration on the behaviour of a number of different systems that are otherwise identical is given in the ESI in Fig. , highlighting that more rapid aggregation, and the formation of larger aggregates, is indeed observed at higher concentrations, with the conccentration dependence of the aggregation rate with eqn (4). Extrapolating the observed chain length dependence (Fig. ) to longer chains (e.g. 180mers, consistent with ref. 12), single-chain folding is expected to be the dominant pathway at concentrations up to approximately 2.4 g/L. These concentrations are above those used in the experiments of up to 1 g/L. The predicted folding behaviour is therefore consistent with the experimental observations for these longer chains at lower concentrations. This kinetic effect, by which the relative rates of single chain folding and multi-chain aggregation are important for predicting the aggregate structure, reconciles the apparent discrepancy between the experimental studies, and highlights the importance of both concentration and chain length for achieving the desired thin-film morphology.