Résumé
For several decades now, mesoporous silica has been a major player for many functional applications, as well as an important model material, representative of the mesostructured family. Its sol-gel synthesis by micelle soft-templating is a method of choice for the deliberate tailoring of particle size, shape and pore texture. Among the variety of related materials, cage-type mesoporous silica has shown remarkable and fascinating structures, including clathrate analogs and quasicrystalline structures. In these materials, the pores are all interconnected through windows, forming cages with well-defined symmetries. This implies that structure directing micelles remain discrete, hence offering a unique opportunity to control materials dimensionality by either restricting, directing or confining the self-assembly of multiple micelles during the silica growth. This strategy led us to the discovery of new low dimensional structures, starting with 0D silica cages formed around single micelles1, and hence without pore periodicity. The structure of these cages was resolved by single particle reconstruction from TEM images, revealing a well-defined dodecahedral symmetry. From this point, the introduction of new polyion complex micelles based on a triple hydrophilic block copolymer resulted in 1D worm-like assemblies, made possible by a precise engineering of the different polymer blocks and intermicellar interactions. Confining the growth of these silica cages at a liquid-liquid interface then led to the formation of 2D superlattices of cages. Modulating the number of cage layers by tuning the syntheses conditions further allowed to observe the progressive emergence of structural order in materials with increasing dimensionality. Beyond their fundamental interest, these low-dimensional structures also constitute well-suited building blocks for the bottom-up assembly of structured materials. Following this reasoning, we developed an innovative approach for the integration of silica nanocages with stereolithography 3D printing3, enabling the direct printing of mesoporous objects with programmable (micro)structures. We further demonstrate the localized implementation of functionalities within printed parts, generating important perspectives for the fabrication of hierarchical 3D structures with high value for catalytic or energy applications. [1] Ma et al., Nature 2018, 558, 577.[2] Aubert et al., Adv. Mater. 2020, 32 (21), 1908362.[3] Aubert et al., Nat. Commun. 2020, 11, 4695.