A General Method for Growing Large Area Mesoporous Silica Thin Films on Flat Substrates with Perpendicular Nanochannels

Abstract

Here we introduce a new synthetic approach to grow mesoporous silica thin films with vertical mesochannels on centimeter-sized substrates via an oil-induced co-assembly process. Adding an oil, i.e., decane, into a CTAB-EtOH-TEOS ammonia solution leads to thin-film formation of mesoporous silica of controlled thickness between 20 and 100 nm with vertical mesochannels on various surfaces. The vertical mesoporous channels were evidenced by grazing incidence small-angle X-ray scattering (GISAXS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) characterizations. Decane played two roles: (a) as a pore expansion agent (up to 5.7 ± 0.5 nm) and (b) inducing vertically oriented hexagonal mesophases of micelle-silica composite. The production of periodic and vertical nanochannels is very robust, over many different substrate surfaces (from silicon to polystyrene), various silica precursors (TEOS, fumed silica, or zeolite seed), and many oils (decane, petroleum ether, or ethyl acetate). This wide robustness in the formation of vertical nanophases is attributed to a unique mechanism of confined synthesis of surfactant-silicate between two identical thin layers of oils on a substrate.

Mesoporous metallic rhodium nanoparticles

“…Making mesoporous frameworks composed of carbon4567, metal oxides89, silica10111213, polymers141516 and metals171819 has led to enhanced performance in catalysis2021, energy conversion and storage2223, surface-enhanced Raman spectroscopy (SERS)2425 and chemical/biochemical sensing26. In particular, the application of mesoporous noble metals in the field of heterogeneous catalysis has distinct and numerous advantages in terms of performance.…”

Towards sustainable ultrafast molecular-separation membranes: From conventional polymers to emerging materials

“…Hence, the technology-readiness level and potential of graphene/graphene oxide-based materials to be manufactured as UMS membranes is marked as medium. [61,254] 2D materials Graphene/Graphene oxide (NF) Filtration-coating High selectivity Far [32,35] Graphene/Graphene oxide with nanochannels (NF) Filtration-coating High selectivity and high permeability Medium [36,37,55,62] Other 2D materials (NF) with nanochannels Filtration-coating High selectivity and high permeability Medium [52,53,58] Other materials Carbon or Si-based materials (NF) CVD/3D printing High selectivity and high permeability Medium [31,169,181] Liquid crystal materials Transcription method High selectivity Far [263][264][265][266] Janus membranes Surface modifications High permeability Far [275,276] 5 Outlook-challenges overhead…”

Macroscopically Oriented Porous Materials with Periodic Ordered Structures: From Zeolites and Metal–Organic Frameworks to Liquid‐Crystal‐Templated Mesoporous Materials

“…Whereas the method described above affords platelets with a limited lateral size, Liu, Mou, and co‐workers recently developed an advanced method for growing films with out‐of‐plane oriented channels over large areas using oil–water interfaces . The addition of a small amount of decane to a typical precursor solution of mesoporous silica led to the formation of a mesoporous silica film (20–100 nm thick) with out‐of‐plane oriented mesochannels over a centimeter scale.…”

“…This progress report presents an overview of recent studies on the synthesis, properties, and applications of porous materials with macroscopically oriented structures ( Table 1 ). The scope of this report is limited to porous materials with nano‐ or mesoscale periodic channels constructed by supramolecular self‐assembly of atomic and/or molecular components, such as zeolites (Section ), MOFs (Section ), mesoporous oxides (Section ), and polymers based on liquid crystals (LCs) (Section ) . In other words, porous materials produced by physical processes, such as anodic aluminum oxides or porous silicones, are beyond the scope of this report.…”