Incorporating organic polymer into silica walls: A novel strategy for synthesis of templated mesoporous silica with tunable pore structure

This paper presents a novel approach to the synthesis of mesoporous silicas with tunable pore size, pore volume and pore structure. Organic poly(furfuryl alcohol) (PFA) was incorporated into silica walls by co-polymerization of furfuryl alcohol (FA) and silica source such as tetraethyl orthosilicate during the triblock copolymer P123 templating process. Mesoporous silicas with wormhole pore structure were obtained by completely burning off organic polymers P123 and PFA from the silica-P123-PFA nanocomposites, and their pore size and pore volume were increased by simply adding a certian amount of FA. TGA, N ₂ sorption, SEM, TEM and FT-IR were used to characterize the silica-P123 and silica-P123-PFA nanocomposites, and their final calcined mesoporous silicas. It is suggested that the P123 templating mechanism is not changed by the addition of FA under our experimental conditions, which is evidenced by the similar pore structure and pore size in the carbonized silica-PFA nanocomposites prepared with the addition of different amount of FA. When the large amount of FA (2.12FA:1SiO₂ by mole) was used in the synthesis, the pore size was expanded from 3.4 nm to 7.4 nm, and the pore volume was increased from 0.46 cm³/g to 1.37 cm³/g. At the same time, the pore size distribution was broadened. The BET surface area of the mesporous silicas was measured to be 632-728 m²/g. As a result, the strategy reported here is simple and effective for tailoring pore size and pore structure of mesoporous silicas in the templating synthesis.