Synthesis and Characterization of Methyltriethoxysilyl-Mediated Mesoporous Silicalites

Mesoporous silica obtained with methyltriethoxysilane as co-precursor in alkaline medium

“…Nitrogen sorption data show that for small to moderate amounts of MTES, mesostructural integrity and the large pore dimensions are retained, thus allowing the variation of the hydrophobicity in a broad range. In previous studies at MTES:TEOS=2:8 molar ratio, the structural order weakened and was lost at a MTES:TEOS =3:7 [17]. In the present work, we have shown that using ethanol in the reaction mixture leads to better pore structure even at the highest tested MTES concentration.…”

“…For the calcined samples, the capillary condensation step is shifted toward lower relative pressure with increasing MTES content. Rabbani et al reported a similar decrease of order for mesoporous silica synthesized with TEOS and MTES already at lower MTES content [17]. Thus, the ethanol added into the reaction mixtures promotes formation of ordered porosity for increased MTES content.…”

“…The second weight loss in the 150-280 °C temperature interval was assigned to partial decomposition and reduction of organics to carbon [22,24], therefore to the CTAB decomposition and from the evaporation of byproducts, generated by the polycondensation of TEOS and MTES [17]. The third weight loss in the 280-380 °C temperature interval is accompanied by an exothermic effect on DTA, indicating oxidation of the low molecular weight fragments of the surfactant and methyl groups [24][25][26][27].…”

“…In a recent study, ordered mesoporous silica was synthesized at 60 ºC with NaOH catalyst, by using MTES together with TEOS, as silica precursors, in different molar ratio, without adding alcohol in the reaction mixture. It has been shown that he increased amount of MTES destroyed the mesoporous channels and the materials became amorphous at 30% MTES content [17].…”

Hybrid mesoporous silica with controlled drug release

“…The attempts of using methylsilane as partial substituent for TEOS resulted in the increase of the surface area, to the significant decrease of the pore size and to the broadening of the pore size distribution. 9,10 Also, the materials stable over time toward water can be obtained due to the enhancement of the surface hydrophobicity induced by increased density of the surface methyl groups. 11 Under the acidic condition, the rate of MTES hydrolysis/polymerization is much greater than that of TEOS.…”