Two‐Dimensional Superstructures of Silica Cages. Issue 21 (9th April 2020)

• Record Type: Journal Article
• Authors: Aubert, Tangi; Ma, Kai; Tan, Kwan W.; Wiesner, Ulrich
• Is Part Of: Advanced materials. Volume 32:Issue 21(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-04-09
• Subjects: 2D materials -- dual structures -- Frank–Kasper phases -- ordered mesoporous materials -- ultrathin membranes; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adma.201908362
• Languages: English
• ISSNs: 0935-9648

Abstract

Abstract: Despite extensive studies on mesoporous silica since the early 1990s, the synthesis of two‐dimensional (2D) silica nanostructures remains challenging. Here, mesoporous silica is synthesized at an interface between two immiscible solvents under conditions leading to the formation of 2D superstructures of silica cages, the thinnest mesoporous silica films synthesized to date. Orientational correlations between cage units increase with increasing layer number controlled via pH, while swelling with oil and mixed surfactants increase micelle size dispersity, leading to complex clathrate type structures in multilayer superstructures. The results suggest that a three‐dimensional (3D) crystallographic registry within cage‐like superstructures emerges as a result of the concerted 3D co‐assembly of the organic and inorganic components. Mesoporous 2D superstructures can be fabricated over macroscopic film dimensions and stacked on top of each other. The realization of previously inaccessible mesoporous silica heterostructures with separation or catalytic properties unachievable via conventional bulk syntheses is envisioned. Abstract : Ultrathin 2D mesoporous superstructures of silica cages are assembled at a liquid−liquid interface. Fine tuning of the synthesis conditions enables thickness and structure control, revealing the emergence of structural order from single layer to multilayer superstructures. Heterostacks of 2D superstructures with varying orientation, composition, and morphology open numerous opportunities for the design of innovative mesoporous materials with hitherto unachievable properties.