Supramolecular Templating of Mesopores

With an appropriate postgelation aging that reorganizes the micropore structure within the frameworks comprising 2D hexagonal mesopores, large 

Functional Polyorganosiloxane Porous Materials from Tri- and Dialkoxysilanes 

As exemplified in the previous section, silsesquioxanes (RSiOi.s) derived from trialkoxysilanes (RSi(OR )s) through sol-gel offer attractive features especially in 

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Nakanishi, K., Sato, Y., Ruyat, Y., and Hirao, K. (2003) Supramolecular templating of mesopores in phase-separating silica sol-gels incorporated with cationic surfactant. /. Sol-Gel Sci. Technol., 26, 567-570. 

Since the discovery of the M41S materials with regular mesopore structure by Mobils scientists [1], many researchers have reported on the synthetic method, characterization, and formation mechanism. Especially, the new concept of supramolecular templating of molecular aggregates of surfactants, proposed as a key step in the formation mechanism of these materials, has expanded the possibility of the formation of various mesoporous structures and gives us new synthetic tools to engineer porous materials [2],... 

Wong, M.S. Jeng, E.S. Ying. J.Y. Supramolecular templating of thermally stable crystalline mesoporous metal oxides using nanoparticulate precursors. Nano Lett. 2001. 1. 637. 

The syntheses of mesoporous materials, with regularly or in purpose designed sized pores by means of the supramolecular templating of a sol-gel process represent a starting point in the design of functional nanostructured materials. 

Template Synthesis of Mesoporous Solids with Supramolecular Assemblies... 

This study demonstrated that the micro-mesoporous composite materials could be synthesized with two-step treatment by microwave using two different templates system with TPABr and MTAB. This formation was controlled by the self-assembly formation of supramolecular templates between MTA micelles and SiO /TPA gels. As varying microwave irradiation time of micro-mesoporous materials, gradually transition from the mesophase to micro-mesophase was occurred. These materials have higher dm spacing of mesoporous materials and lead to transition from mesophase to micro-microphase by an increment of synthetic time, while the calcined products is formed with bimodal and trimodal pore size distribution under microwave irradiation within 3 h. From TG-DTA and PL analysis, the self-assembly formation of supramolecular templates between MTA+ micelles and SiO /TPA+ gels were monitored. 

Since the first synthesis of mesoporous M41S alumosilicates in 1992 [1,2] numerous systems of mesoporous materials have been reported. The principle method of these syntheses consists of the utilisation of lyotropic liquid crystals as supramolecular templates, which act as structure directing agents in order to mesostructure inorganic building units. 

This new family of mesoporous silica and aluminosilicate compounds were obtained by the introduction of supramolecular assemblies. Micellar aggregates, rather than molecular species, were used as structure-directing agents. Then, the growth of inorganic or hybrid networks templated by structured surfactant assemblies permitted the construction of novel types of nanostructured materials in the mesoscopic scale (2-100 nm) [110,113,117],... 

Ying, J. Y, Mehnert, C. P, and Wong, M. S., Synthesis and applications of supramolecular-templated mesoporous materials. Angew. Chem. Int Ed. 38,56 (1999). 

The synthesis of molecular sieves with large pores is of great importance for many applications such as catalysis, separation, adsorption and fabrication of various quantum materials [1-7]. With the recent discovery of hexagonal and cubic large pore mesoporous materials (SBA-15, SBA-16, FDU-1) [2,3], block copolymers have turned out to be valuable supramolecular templates for the synthesis of ordered large pore mesoporous materials because of their facile structure-directing ability, low-cost commercial availability and biodegradability. 

J.Y. Ying, C.P. Mehnert, M.S. Wong, Synthesis and Applications of Supramolecular-Templated Mesoporous Materials , Angew. Chem. Int. Ed., 38,56 (1999)... 

Fig. 8.16. Supramolecular assembly of surfactants to create organised rod-like micelles can template the formation of metal oxides with well defined mesoporous structure, i.e. MCM-41 materials. Adapted from [66].

In 1992, researchers of the Mobil Oil Company introduced a new concept in the synthesis of mesoporous materials. They used supramolecular arrays of surfactant molecules as templating agents in order to obtain mesostructured silicates or alumosilicates which retain after calcination an ordered arrangement of pores with diameters between 2 and 10 nm and a narrow pore size distribution comparable to that of zeolites. These materials called M41S phases give access to the regime of the mesopores which is very interesting for different kinds of new size selective applications, e.g., molecular sieves, catalysis and nanocomposites [1]. 

Ying JY, Mehnert CP, Wong MS (1999) Synthesis and appheations of supramolecular-templated mesoporous materials. Angew Chem Int Ed 38 56... 

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