Chemistry Reference
In-Depth Information
SHAPE PERSISTENT
POLYPHENYLENE-BASED
DENDRIMERS
M
ARTIN
B
AUMGARTEN
,T
IANSHI
Q
IN
,
AND
K
LAUS
M
¨
LLEN
Max-Planck-Institut f¨r Polymerforschung, Ackermannweg 10, D-55128 Mainz, Germany
5.1 INTRODUCTION
Functional organic and inorganic particles are an essential element of today's
materials science [1-3]. Properties such as the surface-to-volume ratio of polymer
lattices or the color control of quantum dots as a result of quantum confinement
provide convincing evidence that “size matters.” There are various ways to fabricate
functional nanoparticles whereby the controls of size, shape, and the chemical
functionalization, both, inside and outside the particles are the key issues. A special
challenge is the design and synthesis of core-shell systems since this approach allows
for the combination of different behaviors such as charge function and charge carrier
mobility [4-6]. Dendrimers play an outstanding role among organic functional
nanoparticles because they can be made molecularly defined [7-12], and polyphe-
nylene dendrimers (PPDs) are a very special family of dendrimers. For instance, the
PPDs offer the highest possible rigidity among all types of dendrimers and possess
high thermal stability, solubility, shape persistence, and structural perfectness [13,14].
Based on the synthetic protocols of the dendritic generations, a large variation of these
molecules has been made available as a result of using different cores, branching
units, and outer phenylene shells (endcapping) [15-18].
Besides additional functional groups to enable further reactions even chromo-
phores and electrophores have been included at will in the cores, the scaffold, and on
