Geoscience Reference
In-Depth Information
Figure 6.33 Assembly of zeolite
CaA crystals on silozane layer on
gold surface and stabilization with
20 nm silica layer
[138]
.
E
O
E
O
E
O
E
O
E
O
E
O
Si
Si
S
S
gold
and sorption in the composite films have been carried out by Yan and Bein
[138]
.
Figure 6.33a and b
shows the assembly of zeolite CaA crystals on a silozane layer
on a gold surface and stabilization with 20 nm silica layer.
Figure 6.34
shows the
mass changes of zeolite silica composite films exchanged with different cations on
a piezoelectric substrate.
Figure 6.35
shows a schematic diagram of the surface
acoustic wave (SAW) device covered with molecular sieve layer.
Figure 6.36
shows the proposed reaction scheme for the design of zeolite layers and films on
organophosphate films: (a) Aluminophosphate nuclei attach on organophosphonate
film and (b) the growth of hexagonal crystals. The SEM pictures have shown that
the AlPO
4
-5 crystals grow with their c-axes oriented similar to the gold surface
(
Figure 6.37
). It was also found that changing the water concentration and tempera-
ture in the hydrothermal synthesis has a profound effect on the orientation
morphology and aspect ratios of the surface-attached crystals.
Table 6.18
gives the
effect of water concentration on the morphology of surface-attached AlPO
4
-5
crystals.
Thus, the molecular selectivity of zeolite thin films can be precisely tuned by
gating the entry of molecules into the zeolite pores.
