0428同步年報-2021-全

Soft Matter 039 The time-resolved FFR-TEM images ( Figs. 3(a−d) ) revealed the coalescence of small prolate silicate micelles into the nanoplates. The silica plates developed into large sheets, followed by 2D hexagonally packed domains. The team traced the self-assembly of the catanionic surfactant- coated P123 micelles upon silicate deposition by SAXS in situ ( Fig 3(e) ). After the silicate deposition, the emergence of three broad signals indicates a formation of lamellar domains derived from a lateral packing along the equatorial plane of the prolate micelles. As the silicification evolves, the lateral structure deteriorates gradually and becomes largely disrupted at 60 min. At 60−190 min, the structure transformed into 2D hexagonally packed nanochannels and then grew into submicrometre-sized domains. The mechanism of formation of mesoporous silica-sheet material SBA ( ⊥ ) is proposed in Fig 3(f) . Beginning from spherical P123 micelles, the addition of SDS/CTAB catanionic surfactants (with SDS in significant excess) leads to negatively charged surfactant-P123 core-shell prolate micelles and their self-assembled prototype nanoplates. This effect is followed by silicate condensation for micellar self-assembling into large silicate thin sheets, within which the silicate micelles form locally in-plane layered packing then transit into elongated micelles of in-plane 2D hexagonal packing (bottom cartoons). Calcination of the silica sheets leads to single-layer, vertically oriented and ordered silica nanochannels with through pores. In the three-component surfactant system undergoing silica condensation, the team demonstrated self-assembly of P123/silicate confined in a SDV-like bilayer (SDS/CTAB)- shelled nanoplates. The end products of the synthesis are mesoporous silica nanochannel plates with a perpendicular channel orientation analogous to that of diatom frustules. In summary, a mechanism of formation of silica sheet is proposed on the basis of large silica deposition nanoplates of SDV-like confinement effects and small silica transport micelles that are like silica transport vesicles, revealed from SAXS, SANS and FFR-TEM. With these analogous features, we have thus defined a synthetic system of porous silica that mimics diatom biogenesis in its primitive form. The reported intricate porous silica formation not only assists future designs of mesoporous silica thin-film materials in a bio-inspired approach but also paves a road towards understanding the formation of biosilica of diatoms under soft confinement. (Reported by Yi-Qi Yeh) This report features the work of Yi-Qi Yeh and her collaborators published in J. Colloid Interface Sci. 584 , 647 (2021). TLS 23A1 Small/Wide Angle X-ray Scattering • SAXS, SANS, FFR-TEM • Materials Science, Chemistry References 1. V. V. Annenkov, E. N. Danilovtseva, V. A. Pal'shin, O. N. Verkhozina, S. N. Zelinskiy, U. M. Krishnan, RSC Adv. 7 , 20995 (2017). 2. Y. Q. Yeh, C. J. Su, C. A Wang, Y. C. Lai, C. Y. Tang, Z. Di, H. Frielinghaus, A. C. Su, U-S. Jeng, C.-Y. Mou, J. Colloid Interface Sci. 584 , 647 (2021).