Research ArticleMATERIALS SCIENCE

Formation of 2D and 3D multi-tori mesostructures via crystallization-driven self-assembly

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Science Advances  15 Apr 2020:
Vol. 6, no. 16, eaaz7301
DOI: 10.1126/sciadv.aaz7301
  • Fig. 1 Examples of 3D multi-tori mesostructures.

    (A) Protocol followed to prepare the multi-tori mesostructures. (B to E) Representative SEM micrographs of spherical hollow mesostructures consisting of a network of toroids. The structures were obtained by the self-assembly of PFS26-b-PS306 in a mixture of 1.02 ml of acetone/decane (25/75, v/v%), containing 20 μl of PFS55-b-PI500 core-crystalline elongated micelles (c = 0.2 mg ml−1), and preheated at 35°C. An aliquot of PFS26-b-PS306 dissolved in THF (8 μl, c = 10 mg ml−1) was then injected, and the solution was annealed for 1 hour at 35°C and cooled to room temperature; TEM grids were prepared within 1 hour after heating. Scale bars, 10 μm (B to D) and 2 μm (E).

  • 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).

  • Fig. 3 Kinetic study of the formation of the toroids constituting the multi-tori mesostructures.

    Six vials were prepared. In each vial, 20 μl 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), 5 min (B), 10 min (C and D), 20 min (E), 30 min (F), and 1 hour (G and H) after injection of PFS26-b-PS306 unimer. The red arrows in (B) point at the elongated micelles that started to appear in the drupelets after 5 min of annealing. Scale bars, 100 nm (A, B, F, and H) and 200 nm (C to E and G).

  • Fig. 4 Understanding the formation of the 3D multi-tori mesostructures.

    SEM micrographs of (A) the edge of a broken 3D multi-tori mesostructured, (B) a broken toroid, and (C and D) the side view of toroids of 3D multi-tori mesostructures. (E) Schematic representation of a micrometer large bumpy shell. (F) Schematic representation of the formation of the toroids. Scale bars, 5 μm (A and C), 100 nm (B), and 500 nm (D).

  • Fig. 5 Effect of an aliquot of MEK on the morphology of 3D multi-tori mesostructures.

    (A to E) Representative SEM micrographs of spherical hollow mesostructures consisting of a network of toroids. The mesostructures were prepared by adding 20 μl of MEK to a mixture of 1.02 ml of acetone/decane (25/75, v/v%), containing 20 μl of PFS55-b-PI500 core-crystalline elongated micelles (c = 0.2 mg ml−1). The solution was preheated 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 for 1 hour at 35°C and cooled to room temperature. TEM grids were prepared within 1 hour after heating. Scale bars, 20 μm (A to D) and 5 μm (E).

  • Fig. 6 Effect of an aliquot of DMAc and ACN on the morphology of multi-tori mesostructures.

    Representative SEM micrographs of mesostructures consisting of a network of toroids. The mesostructures were prepared by adding (A to C) 10 μl of DMAc, (D and E) 20 μl of DMAc, or (F to H) 20 μl of ACN to a mixture of 1.02 ml of acetone/decane (25/75, v/v%), containing 20 μl of PFS55-b-PI500 core-crystalline elongated micelles (c = 0.2 mg ml−1). The solution was preheated 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 for 1 hour at 35°C and cooled to room temperature. The yellow arrows in (C) and (H) point at sections of the monolayer perpendicular to the TEM grid and protruding toward the reader. TEM grids were prepared within 1 hour after heating. Scale bars, 500 μm (A and F), 40 μm (B, D, E, and G), and 10 μm (C and H).

Supplementary Materials

  • Supplementary Materials

    Formation of 2D and 3D multi-tori mesostructures via crystallization-driven self-assembly

    Gerald Guerin, Menandro Cruz, Qing Yu

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