Chemistry Reference
In-Depth Information
Figure 6.2 (a) Gold nanoparticles assembled using PAMAM dendrimers and (b) small angle
X-ray scattering (SAXS) plots of nanoparticle assembly indicating systematic control of inter-
particle distance by dendrimer generations. Reprinted with permission from Frankamp, Boal,
et al. (2002). Copyright 2002 American Chemical Society.
generation confirmed previous studies. Moreover, the surface plasma resonance
(SPR) of resulting thin films exhibited a gradual blueshift over an 84-nm range
with the increase of PAMAM generations (Fig. 6.3). The observed shift of SPR
bands was attributed to a decrease of nanoparticle dipolar coupling with increasing
interparticle spacing. Thus, the manipulation of dipolar coupling between nanoparti-
cles provides a new way to fine-tune the optical properties of nanoparticle assemblies.
By applying the same principle, Rotello's group also showed that dendrimer-
mediated assembly of magnetic nanoparticles (g-Fe
2
O
3
) can directly modulate
Figure 6.3 UV visible spectra of assembled gold nanoparticle thin films by dendrimers of
different generations ranging from G0 to G4. Reprinted with permission from Srivastava,
Frankamp, et al. (2005). Copyright 2005 American Chemical Society.
