Figure 3. In-situ and ex-situ SAXS data of intermediates and MSCs.

(a) In-situ profiles showing the evolution of the intermediate in the induction period, with the overall diameter increasing from 1.05 nm at 30 °C (blue circular symbols) to 1.28 nm at 90 °C (green triangular symbols) and 1.54 nm at 150 °C (red squared symbols). Inset shows the model of monodisperse intermediates. (b) Ex-situ SAXS profiles for the 130 °C/30 min Intermediate 2 (dispersed in dry toluene with the 1–4 volume ratio of sample to toluene, grey star symbols), MSC-371 (in 0.5 ml OTA for 10 min, blue circular symbols), MSC-417 (in the mixture of 0.2 ml OTA, 0.2 ml ethanol and 0.1 ml toluene for 60 min, green triangular symbols) and MSC-448 (in the mixture of 0.1 ml ethanol and 0.4 ml toluene for 10 min, red square symbols). Each of the three MSC dispersions was prepared from the same 130 °C/30 min sample in toluene shown in Fig. 4b (grey) of 0.5 ml. The diameters of the three types of MSCs (D₁, primary structure) are 0.97, 1.39 and 1.65 nm, respectively. The overall diameters of the MSC aggregation (D₂, secondary structure) are 19.48, 21.77 and 24.24 nm, respectively. Inset shows the model of MSCs and their aggregation. The concentration of the in-situ sample is higher than those of the ex-situ samples. Details can be found in Methods.