pubs.acs.org/Langmuir © 2010 American Chemical Society
One-Step Synthesis of Monodisperse and Hierarchically Mesostructured Silica Particles with a Thin Shell Hongmin Chen,† Tao Hu,† Xinmeng Zhang,†,§ Kaifu Huo,†,^ Paul K. Chu,*,† and Junhui He*,‡ †
Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, China, ‡Functional Nanomaterials Laboratory, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences (CAS), Beijing 100190, China, §State Key Lab of Advanced Welding Production Technology, School of Materials Science & Engineering, Harbin Institute of Technology, Harbin 150001, China, and ^College of Materials and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081, China Received May 4, 2010. Revised Manuscript Received July 12, 2010 Monodisperse, uniform, and hierarchically mesostructured silica particles with a thin shell have been fabricated via onestep synthesis using dodecanethiol (C12-SH) and CTAB as dual templates. A series of hierarchically mesostructured silica particles with a morphology similar to that of pomegranate can be obtained by simply adjusting the mass ratio of C12-SH to CTAB. When the mass ratio is increased, a mesophase transformation occurs from an ordered 2D hexagonal structure to a mesostructured cellular foam in the core of the hierarchically mesoporous silica particles. These unique silica particles are characterized by small-angle X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FT-IR), and nitrogen adsorption-desorption measurements. The formation mechanism of the hierarchically mesostructured silica particles with a thin shell is proposed according to the experimental results. Synergistic self-assembly of C12-SH and CTAB in the solution is believed to play a key role in mediating the formation of these hierarchical silica mesostructures, and the hydrophobic dodecanethiol can act as both the swelling agent for CTAB micelles and coagent for the formation of a microemulsion with CTAB micelles. This synthesis method is simple, straightforward, and suitable for the preparation of the other biomineral nanostructures that are unique scaffolds in biological, medical, and catalytic applications.
1. Introduction Recently, synthesis of hierarchically silica mesostructures has attracted much attention due to promising applications1 and the possibility to elucidate the fundamental mechanisms about biomineralization.2 The important goal and big challenge concerning the design and fabrication of silica mesostructures are to *To whom correspondence should be addressed. E-mail: paul.chu@ cityu.edu.hk (P.K.C.);
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13556 DOI: 10.1021/la101778z
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Published on Web 07/21/2010
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Chen et al.
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Article Table 1. Summary of the Different Amounts of C12-SH and CTAB Added with R Values Change in Reaction Solution sample
R
C12-SH (mL)
CTAB (g)
corresponding figure
S1 S2 S3 S4 S5 S6 S7 S0
0.04 0.08 0.20 0.40 0.80 2.0 4.0 0
0.01 0.02 0.05 0.10 0.20 0.50 1.00 0
0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2
Figures 1a and 2 Figures 1b and 3 Figures 1c and 4 Figures 1d and 5 Figure 6a Figure 6b Figure 6c Figure 7
Table 2. Physicochemical Properties of Fabricated Mesoporous Silica Nanospheres sample
d (nm)a
BET surface area (m2/g)
pore volumeb (cm3/g)
pore size distributionc (nm)
S1 4.211 763 0.299
