Research ArticleMATERIALS SCIENCE

Artificial 3D hierarchical and isotropic porous polymeric materials

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Science Advances  11 May 2018:
Vol. 4, no. 5, eaat0713
DOI: 10.1126/sciadv.aat0713
  • Fig. 1 Self-assembly of PS636-b-PtBA250 into a hierarchical structure.

    (A) Optical image of a PS636-b-PtBA250 film cast from 20 wt % solution in 1:3 (wt %) THF/DMF on a glass plate. (B) Corresponding SEM cross-sectional image after 5 min of evaporation with details of a macrocavity and its fine mesoporous structure. (C) Plot of the average cavity diameter, measured by SEM, as a function of evaporation time (10, 20, and 30 s); effect of the addition of 6 wt % β-CD (calculated with respect to block copolymer amount) to the casting solution.

  • Fig. 2 Macroscale and mesoscale long-range order of hierarchical structures obtained from PS636-b-PtBA250 solutions in 1:3 (wt %) DOX/DMF after 5 min of evaporation.

    (A) Three-dimensional reconstruction of SEM images by serial block face. (B) SEM surface. (C) Cross-sectional TEM image stained with RuO4; (D) TEM tomography: 3D surface rendering of a thin section of the film.

  • Fig. 3 SAXS characterization of the mesoscale order of PS636-b-PtBA250 in solutions with different copolymer concentrations (wt %) in 1:3 (wt %) THF/DMF.

    (A) Plain solutions and (B) solutions with 6 wt % β-CD. (C) Periodic distance in solution as a function of copolymer concentration. a.u., arbitrary units.

  • Fig. 4 Macroscale structure formation.

    Scheme of NG development: Nuclei growth and simultaneous solvent flow from the polymer-rich matrix to the polymer-depleted nuclei (blue arrows); solvent flow in the Plateau border between nuclei (red arrows).

  • Fig. 5 CaCO3 mineralization in block copolymer scaffolds.

    (A) SEM images of scaffolds obtained from PS636-b-PtBA250 solutions in 1:3 (wt %) DOX/DMF after 5 min of evaporation. (B) SAXS and (C) SEM of the scaffold after hydrolysis with TFA for 24 hours. (D) Scaffolds filled with CaCO3 generated by the reaction between CaCl2 and (NH4)2CO3. (E) Remaining inorganic structure after polymer dissolution.

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/4/5/eaat0713/DC1

    Supplementary text on Flory-Huggins parameter estimation

    table S1. Flory-Huggins interaction parameters (χ) between copolymer blocks and the solvent mixture.

    fig. S1. Hierarchical structure of PS636-b-PtBA250 films obtained after evaporation times varying from 10 to 30 s, before immersion in the nonsolvent bath.

    fig. S2. Hierarchical structure of PS636-b-PtBA250 films after long evaporation times.

    fig. S3. Influence of the addition of β-CD to the PS636-b-PtBA250/DOX/DMF system on the macroscale.

    fig. S4. Influence of the addition of β-CD to the PS636-b-PtBA250/DOX/DMF system on the mesoscale.

    fig. S5. Mesopore dimensions of PS636-b-PtBA250 films prepared from solutions in 1:3 (wt %) DOX/DMF.

    fig. S6. Effect of the relative humidity on the cross-section morphology of PS636-b-PtBA250 films obtained from solutions in 1:3 (wt %) DOX/DMF, after 5-min evaporation.

    fig. S7. Hierarchical structure prepared from PS677-b-PtBA180 dissolved in 1:3 (wt %) DOX/DMF.

    fig. S8. Hydrolysis of preformed hierarchical PS636-b-PtBA250 films to PS-b-PAA.

  • Supplementary Materials

    This PDF file includes:

    • Supplementary text on Flory-Huggins parameter estimation
    • table S1. Flory-Huggins interaction parameters (χ) between copolymer blocks and the solvent mixture.
    • fig. S1. Hierarchical structure of PS636-b-PtBA250 films obtained after evaporation times varying from 10 to 30 s, before immersion in the nonsolvent bath.
    • fig. S2. Hierarchical structure of PS636-b-PtBA250 films after long evaporation times.
    • fig. S3. Influence of the addition of β-CD to the PS636-b-PtBA250/DOX/DMF system on the macroscale.
    • fig. S4. Influence of the addition of β-CD to the PS636-b-PtBA250/DOX/DMF system on the mesoscale.
    • fig. S5. Mesopore dimensions of PS636-b-PtBA250 films prepared from solutions in 1:3 (wt %) DOX/DMF.
    • fig. S6. Effect of the relative humidity on the cross-section morphology of PS636-b-PtBA250 films obtained from solutions in 1:3 (wt %) DOX/DMF, after 5-min evaporation.
    • fig. S7. Hierarchical structure prepared from PS677-b-PtBA180 dissolved in 1:3 (wt %) DOX/DMF.
    • fig. S8. Hydrolysis of preformed hierarchical PS636-b-PtBA250 films to PS-b-PAA.

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