Fig. 2. SEM images of the 3D multi-tori mesostructures at short annealing times.

Twenty microliters of a decane solution of PFS₅₅-b-PI₅₀₀ seeds (c = 0.2 mg ml⁻¹) was added to 1 ml of acetone/decane mixture. The solution was then left to equilibrate at 35°C, and an aliquot of PFS₂₆-b-PS₃₀₆ dissolved in THF (8 μl, c = 10 mg ml⁻¹) was injected. The solution was then annealed at 35°C. Samples were taken out from the solution and deposited on a TEM grid 30 s (A to C) and 5 min (D to F) after injection of PFS₂₆-b-PS₃₀₆ unimer. The yellow arrows in (C) and (F) point at holes forming in the drupelets. Scale bars, 20 μm (A, B, D, and E) and 2 μm (C and F).