Biomedical Engineering Reference
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Hexagonal
array
Surfactant micelle
Micellar rod
Silicate
Calcination
1
MCM-41
Silicate
2
FIGURE 8.5 Two mechanistic liquid-crystal templating pathways for the formation of MCM-41 proposed
by Beck et al.: (1) liquid crystal phase initiated and (2) silicate anion initiated. (Reprinted from Beck, J.S. et al.,
J. Am. Chem . Soc. , 114, 10834, 1992.)
(a)
(b)
0.5 ยต m
100 nm
(c)
(d)
100 nm
100 nm
(e)
(f)
100 nm
100 nm
FIGURE 8.6 SEM (a and b) and TEM (300 kV) micrographs of the MCM-41 type mesoporous silica nano-
spheres (MSNs) with an average particle size of 200 nm (c and e). The N 2 adsorption/desorption isotherms
measurement of the material revealed a surface area of 941.0 m 2 /g and the average pore diameter of 2.3 nm.
The MCM-41 type of mesoporous channel structure of the nanospheres is visualized with the parallel stripes
(c) and the hexagonally packed light dots (e) shown in the micrographs. The TEM micrographs (d and f) of the
CdS-capped MSNs exhibit aggregations of CdS nanoparticles on the MSN surface, represented by dots in the
areas indicated by arrows. The TEM micrographs (d-f) were taken on ultramicrotomed samples with section
thickness of 60-80 nm. (Reprinted from Lai, C.Y. et al., J. Am. Chem. Soc. , 125, 4451, 2003.)
 
 
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