Synthesis of Mesoporous Silica Materials with Hydroxyacetic Acid Derivatives as Templates via a Sol-Gel Process

Abstract

A series of mesoporous silica materials were synthesized via HCl-catalyzed sol-gel process of tetraethyl orthosilicate at 60°C in the presence of nonsurfactant compounds such as hydroxyacetic acid (HA), lactic acid (LAC), 2-hydroxyisobutyric acid (HIBA) and diphenylglycolic acid (DPGA) as templates or pore-forming agents. After the removal of the nonsurfactant template compounds from the template-containing SiO2 composite, mesoporous silica materials were obtained. Results from Brunauer–Emmett–Teller (BET), powder X-ray diffraction (XRD), and transmission electron microscopy (TEM) experiments identified the formation of mesopores. Nitrogen adsorption-desorption isotherms showed that pore parameters increased with the template concentration except for the DPGA system. However, the pore parameters did not simply increase with the size of the template molecules. These results revealed that the molecular structure, molecular affinity, number of hydrophobic groups and steric hindrance played a significant role on the pore size of the final materials.