Small-angle neutron scattering investigations of layer-block dendrimers in aqueous solutions

Structures of poly(trimethyleneimine)/mono(amido amine) dendrimer with hydroxyl end groups and poly(amido amine) dendrimer with galactose having glycopeptide end groups were characterized in aqueous solutions and compared with that of poly(amido amine) dendrimer with hydroxyl end groups reported before (Langmuir 1999, 15, 4076). External contrast variation results of small-angle neutron scattering suggested the segment density distribution in dendrimer, The segment density distribution and solvent penetration amount in the fifth generation dendrimers were evaluated on the basis of the five concentric layers model. Those differed among three dendrimers, depending on the hydrophilic or hydrophobic interior segment and the small or bulky terminal group. Moreover, the profile of segment density distribution is not necessarily consistent with that of solvent penetration amount.