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surface and formed arrays, therefore, larger and heavier aggregation of par-
ticles was obtained, as shown in Figure 7.13e, 7.13a, and 7.13f.
In summary, following this study, electrophoretic deposition of nanoparti-
cles templated by LLC can provide a promising approach for obtaining densely
arranged and ordered nanoparticles, and their morphology can be in tune with
the water layer width, the electric fi eld strength, and deposition time.
Recently, Yoshida et al. (2010) introduced a method that can drastically
simplify the fabrication of gold nanoparticle-TLC suspensions and can be
applicable to any type of material and LC phase. The authors demonstrated
that metal nanoparticle-TLC suspensions can be fabricated by sputter depos-
iting the target material (gold) on the host liquid crystal.
They exploited the fact that certain LC molecules possess a vapor pressure
smaller than 1 Pa at room temperature, which is suffi cient to undergo the
sputter deposition process, which is performed at a pressure of a few to several
tens of pascals. Several nematic samples are shown in Figure 7.15a, including
pure 4-pentyl-40-cyanobiphenyl (5CB) forming a nematic LC structure,
between 24 and 35°C, and after sputter deposition of gold (for 30 s, and 3, 10,
(a)
(b)
Figure 7.15
(a) Photograph of the nematic LC 5CB deposited with gold for various
durations and (b) extinction spectra of 5CB deposited with gold for various periods,
as indicated in the fi gure (Yoshida et al., 2010).
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