Synthesis of Ordered Cubic Periodic Mesoporous Organosilicas with Ultra-Large Pores

Abstract

Highly ordered ethylene bridged periodic mesoporous organosilica (PMO) materials with ultra-large pore sizes up to 14.7 nm were successfully synthesized by using triblock copolymer F127 as a template and 1,3,5-trimethylbenzene (TMB) as a swelling agent. SAXS and TEM measurements show that PMO products have a face-centered cubic (space group of Fm3̄m) mesostructure. The influence of reaction temperature and acidity of the solution on the mesostructure of the PMO products were systematically studied. The pore size can be gradually expanded as the temperature decreases, and ordered PMOs can be obtained at a temperature even down to 5 °C with a relatively low acidity. As compared with mesoporous silica materials synthesized at identical conditions, our experimental results reveal that different hydrophobicity between precursors, bis(trimethoxysilyl)ethane and tetraethyl orthosilicate, may influence the swelling capacity of F127 micelles with TMB as well as the phase behavior of triblock copolymer F127, resulting in the different physicochemical properties of the final products.

Tunable Assembly of Organosilica Hollow Nanospheres

“…The fabrication of organosilicas in nanospherical morphology has attracted much research attention because of their potential applications in catalysis, drug delivery, and protection materials for biomolecules. [5][6][7][8][9][10][11] Due to the difficulty in the synthesis of hollow nanospheres, there are only limited reports for the synthesis of OHNs. [5][6][7][8][9][10][11] The first OHNs (particle size in the range 300-800 nm) with ethylene-bridging group and highly ordered mesoporous structure in the shell were reported by Lu's group through a vesicle and a liquid crystal "dual templating" approach.…”

A new example of periodic mesoporous SiCO glasses with cubic symmetry stable at 1000.DEG.C

“…1(a)) using synchrotron radiation reveals one well-resolved peak at very low angle (2u＝0.73) whilst a second less-intense signal appears at higher angle (2u＝1.16). In the literature 29),31), 32) for similar systems, cubic phases (Fm3m or Im3m) were already reported. In the present case, the two signals can be tentatively indexed as the (111) and (220) reflections (d＝ 12.6 nm and 7.6 nm respectively) of a Fm3m cubic phase with a lattice constant a＝21.5 nm.…”

Direct Synthesis of Zr‐Containing Hybrid Periodic Mesoporous Organosilicas with Tunable Zirconium Content

“…Actually, no distinct difference can be found between this observation and that for P123-templated PMOs synthesized under various conditions such as such salt-assisted acidic synthesis [7,37] or the true-liquid-crystaltemplating (TLCT) approach, [43] which strongly indicates the outstanding promoting effects of the salt pair in this synthetic system though the zirconium salt amount is very small; the function of both salts is entirely similar to that of reported Na(K)Cl/HCl combinations used for the synthesis of highly ordered mesostructures templated by block copolymers. [7,35,44,45] Figure 6. TEM micrographs of the samples synthesized by using the ZrOCl 2 -NaCl pair with Si/Zr = 10 (A, B) and 100 (C, D).…”