Facile Synthesis of Monodisperse Spherical MCM-48 Mesoporous Silica Nanoparticles with Controlled Particle Size

Abstract

A rapid and facile synthesis route to the monodisperse spherical MCM-48 mesoporous silica nanoparticles (MSN) with cubic <i>Ia</i>3̅<i>d</i> mesostructure is developed based on the modified Stöber method. The phase domain of MCM-48-type MSNs can be extended by controlling the stirring rate and molar ratios of silica source and surfactant. The formation of monodispersed spherical MCM-48-type MSNs is obtained using triblock copolymer Pluronic F127 as a particle size designer. The average size of monodisperse spherical MSN can be controlled within the range of 70−500 nm depending on the amount of F127. Moreover, the pore diameter of MSNs can be precisely controllable in pore diameters from 2.3 to 3.3 nm using different alkyl chain surfactants and simple posthydrothermal treatment. An investigation of MCM-48-type MSN materials using powder X-ray diffraction, transmission electron microscopy, scanning electron microscopy, and nitrogen physisorption clearly reveals that MSNs show high specific surface area, high pore volumes, controllable morphological aspects, and tunable pore diameters. The MCM-48-type MSNs thus obtained are demonstrated as a good hard template for the preparation of other mesoporous nanoparticles, such as mesoporous metal oxides. The present discovery of the extended synthesis conditions and the binary surfactant system in MCM-48 synthesis offers reproducible and facile synthesis of the monodisperse spherical MCM-48 mesoporous silica nanoparticles with precise structural control, and thus has vast prospects for future applications of ultrafine mesostructured nanoparticle materials.