Résumé
Mesoporous silica is a key material, representative of the mesostructured materials 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. Cage-type mesoporous silica in particular has shown remarkable structures, including low-dimensional nanostructures and clathrate analogs.[1,2] They imply that structure directing micelles can remain discrete during their co-assembly with silica. This offers unique control over material dimensionality by restricting, directing, or confining micelle self-assembly during silica growth. In this study, polyion complex (PIC) micelles were explored as alternative templating and functionalizing agents to conventional surfactants. These PIC micelles are formed via electrostatic complexation between a polyacid-containing block copolymer and a cationic partner (e.g., oligochitosan), enabling fine-tuning of the micelle characteristics and of their interactions by adjusting their block composition. For the first time, we employed a triple-hydrophilic block copolymer, namely polyacrylamide-b-poly(acrylic acid)-b-poly(poly(ethylene oxide) methyl ether acrylate), PAm-b-PAA-b-POEGMEA, which directed the formation of 0D cage-type silica nanoparticles formed around individual micelles.[3] By selectively releasing spatial restrictions, we further achieved well-defined 1D and 2D mesoporous silica nanostructures. These low-dimensional architectures constitute well-suited building blocks for the bottom-up assembly of structured materials. The unique rheological properties of 1D nanostructures, in particular, can be exploited for the formation of hierarchical and functional monoliths of high value for environmental or catalytic applications.REFERENCES[1] K. Ma, Y. Gong, T. Aubert, M.Z. Turker, T. Kao, P.C. Doerschuk, U. Wiesner, Nature 2018, 558, 577.[2] T. Aubert, K. Ma, K.W. Tan, U. Wiesner, Adv. Mater. 2020, 32, 1908362.[3] A. Vashishtha, A. Phimphachanh, T. Gaillard, J. Schmitt, C. Gerardin, G. Rydzek, T. Aubert, ACS Nano 2024, 18, 29008-29020.