Sol-gel polymerization: analysis of molecular mechanisms and the effect of hydrogen

Generation of Atomistic Models of Periodic Mesoporous Silica by Kinetic Monte Carlo Simulation of the Synthesis of the Material

“…34 The effect of the catalyst is sufficient to achieve a hydrolysis rate that is roughly 30 times faster than the rate of condensation of silicic acid monomers. Thus the fraction of unhydrolyzed TEOS in the synthesis solutions is negligible 21 and can be ignored in the simulation.…”

Effect of Sol-Gel Ageing Time on Three Dimensionally Ordered Macroporous Structure of 80SiO2-15CaO-5P2O5 Bioactive Glasses

“…Tetraethyl orthosilicate (TEOS), calcium nitrate tetrahydrate (Ca(NO3)2-4H2O), triethyl phosphate (TEP), PI23 (EOzo-POvo-EO.o), ethanol (C2H5OH), and hydrochloric acid (HCl) were successively mixed together. The solution was vigorously stirred at room temperature by the magnetic stirrer to obtain a clear sol (hydrolysis reaction) and further stirred to reach the gel point (condensation reaction) [2,11,16]. To obtain 3D0M structure, PMMA colloidal crystals (sphere diameter is 350 nm) were completely immersed in this so!.…”

“…The key compositions for bioactivity of bioacfive glasses are approximately (30-55) wt% of SÍO2, (15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30) wt% of CaO, (20)(21)(22)(23)(24)(25) wt% of Na20, and (4-7) wt% of P2O5 [2]. The bone-bonding ability of these bioactive glasses is determined from the biodegradable, the dissolution rate of ions when exposed to physiological fluids, the formation of new bones and sfimulation of osteoblast.…”

Effect of sodium chloride on gelatinization of silicic acid and the formation of novel polysilicic acid crystals

“…Extensive studies have been conducted in the middle of last century and the detailed mechanism is well understood for the silicic acid polymerization processes, where silicic acid was formed by either the neutralization of sodium silicate with acid [1][2][3][4][5][6][7] or the hydrolysis of alkyl silicate [8][9][10][11]. However, the precise mechanism for the effects of electrolytes on the gelatinization process has not been fully understood yet and conflicting results have been reported.…”

“…However, the precise mechanism for the effects of electrolytes on the gelatinization process has not been fully understood yet and conflicting results have been reported. Martin and Garofalini [11] studied the mechanisms of sol-gel polymerization using analog computation and investigated the effect of proton on silicon alkoxides catalyzed by acids or bases at low temperatures. They suggested that acid-catalyzed systems formed a more open, less cross-linked monolith structure, whereas the basic catalyzed systems created highly cross-linked colloidal particles.…”