PHYS01200704032 Debes Ray - Homi Bhabha National Institute

f(R)
f(R)
Chapter 6: High-Yield Synthesis of Gold Nanoparticles
with increasing gold salt concentration. The calculated size distributions of the nanoparticles
with increasing concentration for some of the systems are shown in Figure 6.13.
0.008
0.1% HAuCl 4
+ 0.1% Na 3
Ct
0.008
0.2% HAuCl 4
+ 0.2% Na 3
Ct
0.006
0.004
Mean size ~ 14.6 nm
Polydispersity ~ 0.45
0.006
0.004
Mean size ~ 15.1 nm
Polydispersity ~ 0.42
0.002
0.002
0.000
0 10 20 30 40 50
0.008
0.5% HAuCl 4
+ 0.5% Na 3
Ct
0.000
0 10 20 30 40 50
0.008
1% HAuCl 4
+ 1% Na 3
Ct
0.006
Mean size ~ 18.3 nm
Polydispersity ~ 0.4
0.006
Mean size ~ 23.6 nm
Polydispersity ~ 0.33
0.004
0.004
0.002
0.002
0.000
0 10 20 30 40 50
Size (nm)
0.000
0 10 20 30 40 50
Size (nm)
Figure 6.13. The calculated size distributions of gold nanoparticles in 1wt% P85 at varying
gold nanoparticle concentration.
SAXS data of nanoparticles with different gold salt concentrations are shown in
Figure 6.14. Since scattering length is proportional to the atomic number in the case of X-
rays, there is very low contrast for hydrogenous systems such as block copolymer whereas
higher Z elements such as gold show a strong contrast (Table 6.1). Therefore, SAXS data are
mostly from the gold nanoparticles (scattering from block copolymers is negligible). The
mean size of the nanoparticles increases and polydispersity decreases with the increase in
gold salt concentration as shown in Table 6.3 and are found to be consistent with that
obtained from SANS. The resultant size and size distribution of gold nanoparticles is decided
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