Chemistry Reference
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Figure 11.7 Solvent-sensitive conformational changes of Fr´chet-type poly(aryl ether)
dendrimers with poly(ethylene glycol) termini.
behavior of polyelectrolyte star polymers (Jusufi et al. 2002a, 2002b). Indeed, the
hydrodynamic radii of carboxylic acid terminated arborol dendrimers, determined
by
1
H diffusion ordered spectroscopy NMR, expand as the acids are ionized with
increasing pH (Newkome, Young, et al. 1993; Young et al. 1994). Similarly,
amine-terminated dendrimers expand as the terminal amines are protonated with
decreasing pH (Young et al. 1994). The pH-dependent behavior of these dendrimers
has been attributed to the development of coulombic repulsions between charged
Figure 11.8 Structures of (a) parent poly(propylene imine) dendrimer and (b) fully
quaternized form, which presents both hydrophilic triethyleneoxy methyl ether (TEO) and
hydrophobic octyl chains at every terminal position.
