Nematic suspension of a microporous layered silicate obtained by forceless spontaneous delamination via repulsive osmotic swelling for casting high-barrier all-inorganic films

Abstract

Exploiting the full potential of layered materials for a broad range of applications requires delamination into functional nanosheets. Delamination via repulsive osmotic swelling is driven by thermodynamics and represents the most gentle route to obtain nematic liquid crystals consisting exclusively of single-layer nanosheets. This mechanism was, however, long limited to very few compounds, including 2:1-type clay minerals, layered titanates, or niobates. Despite the great potential of zeolites and their microporous layered counterparts, nanosheet production is challenging and troublesome, and published procedures implied the use of some shearing forces. Here, we present a scalable, eco-friendly, and utter delamination of the microporous layered silicate ilerite into single-layer nanosheets that extends repulsive delamination to the class of layered zeolites. As the sheet diameter is preserved, nematic suspensions with cofacial nanosheets of ≈9000 aspect ratio are obtained that can be cast into oriented films, e.g., for barrier applications.

Fabrication of Bragg stack films of clay nanosheets and polycations via co-polymerization of intercalated monomers and functional interlayer cations

“…Most successful examples were therefore reported for aqueous dispersions. [24][25][26][27] Dudko et al were able to transfer 1D dissolution of synthetic fluorohectorite into different organic solvents. This required hydrophobization of the interlayer Na + cation, which was achieved by complexing the sodium cation in the interlayer space with crown ethers.…”

Exfoliating layered zeolite MFI into unilamellar nanosheets in solution as precursors for the synthesis of hierarchical nanocomposites and oriented films

“…There had been no indications nor proof of layer dispersion into a solution by direct or simple treatments, like ultrasonication, in any of the previous reports. [25][26][27][28][29][30] In one study, zeolite layers of MWW and MFI coated with surfactants were indeed dispersed into monolayer nanosheets in solution but through a multi-step process using twin-screw extrusion. It produced very low yields of the dispersed layers, which together with the surfactant coating and complicated preparation methodology presented very limited options for postsynthetic exploitation.…”

Fabricating defogging metasurfaces via a water-based colloidal route

“…The nanosheet sandwich would be chosen from a steadily growing variety created via 1D dissolution 40 like layered titanates, 80 perovskites 81 or zeolites. 82 Many protocols applying nanoparticles for metasurface fabrication, the nanoparticle inks are isotropic and have no internal structure and therefore must be assembled e.g. via molds to for metamaterial properties to emerge, while in our approach each individual AuDS already represents a nano-metasurface that self-assembles driven by the anisotropy of the nanosheets to provide amplified macro-effect.…”