Pore-expansion of monodisperse mesoporous silica spheres by a novel surfactant exchange method

Abstract

By adapting a novel surfactant exchange method, in which surfactants inside mesopores are completely exchanged by surfactants with longer alkyl chain lengths, pore-expansion of monodisperse mesoporous silica spheres (MMSS) with radially ordered hexagonal regularity was attained while retaining spherical morphology and high monodispersity.

Role of Organic and Inorganic Additives on the Assembly of CTAB-P123 and the Morphology of Mesoporous Silica Particles

“…At low CTAB/P123 mol ratios (3.0 and 4.0) and 0.25 M SO 4 2-ions, besides the very high diffraction intensity of the (100) plane, the other diffraction lines (110) and (200) are also better resolved; see Figure 1. Moreover, in the presence a 0.5 M SO 4 2-concentration, diffraction lines originating from (210) and (300) planes are also observed, Figure 1. All diffraction lines can be indexed to a well ordered 2D hexagonal mesostructure with a unit cell parameter a of 10.2 nm.…”

“…Figure 1 shows the PXRD patterns of the mesoporous silica particles, synthesized at two different SO 4 2-ion concentrations and two different CTAB/P123 mol ratios. In the absence of SO 4 2-ion, the PXRD of the silica particles displays one sharp diffraction line due to the (100) plane and relatively broad and overlapped (110) and (200) lines of the 2D hexagonal mesostructure. At low CTAB/P123 mol ratios (3.0 and 4.0) and 0.25 M SO 4 2-ions, besides the very high diffraction intensity of the (100) plane, the other diffraction lines (110) and (200) are also better resolved; see Figure 1.…”

“…In the absence of SO 4 2-ion, the PXRD of the silica particles displays one sharp diffraction line due to the (100) plane and relatively broad and overlapped (110) and (200) lines of the 2D hexagonal mesostructure. At low CTAB/P123 mol ratios (3.0 and 4.0) and 0.25 M SO 4 2-ions, besides the very high diffraction intensity of the (100) plane, the other diffraction lines (110) and (200) are also better resolved; see Figure 1. Moreover, in the presence a 0.5 M SO 4 2-concentration, diffraction lines originating from (210) and (300) planes are also observed, Figure 1.…”

“…Ozin et al investigated for the first time various shapes in powder samples obtained from an acidic solution of CTAB and a silica source. 3 Since then, the ordered mesoporous silica particles have been synthesized in various morphologies, such as spheres, [4][5][6] crystal-like, [5][6][7][8] wormlike, 3,6,9,10 hollow spheres, 11 gyroid, 8,9 and toroids etc. 8,12 The morphology, monodispersity, pore size and pore structure are some of the key parameters that need to be addressed for many applications, such as drug delivery systems, photonic crystals, chromatography, and catalysis.…”

“…8,12 The morphology, monodispersity, pore size and pore structure are some of the key parameters that need to be addressed for many applications, such as drug delivery systems, photonic crystals, chromatography, and catalysis. 4,10,[13][14][15][16] The pluronic surfactants are commanly used in many investigations because of their nontoxic, cheap and excellent aggregation properties. [17][18][19] These surfactants are triblock copolymers with a relatively hydrophobic group, poly(propylene oxide) (PPO), at the middle and relativly hydrophilic, poly(ethylene oxide) (PEO), head groups at both ends of the polymer (PEO x -PPO y -PEO x ).…”