Monolayer Assembly of Zeolite Crystals on Glass with Fullerene as the Covalent Linker

Abstract

Glass plates tethered with 3-aminopropyl groups were prepared and fullerene (C60) was mounted onto the amine groups via NH insertion of the terminal amine moiety into one of the double bonds of fullerene. Cubic zeolite-A crystals covered with 3-aminopropyl groups on the external surface were independently prepared by treating the crystals with (3-aminopropyl)triethoxysilane. The zeolite-A crystals readily assembled in the form of monolayers on the fullerene-tethering glass substrates when they were allowed to contact in boiling toluene. The assembled zeolite-A monolayers remained intact even after sonication for 5 min in toluene. In contrast, the assembly of zeolite crystals does not occur if the tethering of either 3-aminopropyl or fullerene is omitted. Based on the two contrasting results, the monolayer assembly of zeolite crystals on glass is proposed to occur by formation of a large number of propylamine−fullerene−propylamine covalent linkages between each zeolite crystal and the glass substrate. Scanning electron microscope images revealed that zeolite-A crystals assemble with a face pointing normal to the plane of the substrate. The monolayers consist of small domains comprised of about 110 closely packed zeolite-A crystals aligned in uniform three-dimensional orientation. The same procedure also worked well for the monolayer assembly of larger ZSM-5 crystals. Migration of the weakly bound zeolite crystals over the glass substrate driven by a large number of hydrogen bonds between the surface-bound amine groups on the neighboring crystals is proposed to play an important role in inducing the close packing.

Mesophase behaviour of polyhedral particles

“…Indeed, our calculations of mobility coefficients indicate that ``time'' or dynamics is a key consideration in characterizing the liquid crystalline character of phases that otherwise possess a significant degree of `static' positional order. While 2D ordered assemblies have been experimentally observed for cubes 36 and HP 37 , experimental verification of the various structures predicted in this study is yet to be achieved.…”

Organization of Zeolite Microcrystals for Production of Functional Materials

“…Among various covalent linkages (Figure 4a-g) 3,4,6,8,15,19 the ether linkage formed by reaction between surfacetethered halopropyl groups and hydroxyl groups ( Figure 4g) 4 has been most widely used due to its simplicity. Characterization of different types of linkages in terms of number density, thickness, and roughness of each linker was possible by X-ray reflectivity.…”

On the formation of vertically oriented MCM-22 zeolite crystal films

“…The self-assembly of zeolite crystals on a substrate resulted in oriented arranging, and zeolite crystals align with their largest faces adhered to the surface [15,16]. The oriented growth of zeolite ®lms and membranes from direct hydrothermal synthesis can also be related to the orientation of zeolite crystals by self-assembly, and the crystals would also favor the orientation with their largest faces parallel to the surfaces.…”

“…Several di erent strategies have been taken to prepare oriented zeolite ®lms and membranes. One approach is the self-assembly of zeolite crystals on a smooth surface, by which oriented zeolite A and ZSM-5 ®lms have been synthesized [15,16]. The crystal orientation can be well controlled through self-organization of zeolite crystals, but the ®lms obtained are not continuous.…”