| Dendrimers are structurally complex, regularly branching polymers whose physical properties are dominated by their high functional group density. Since their inception in the 1980's new synthetic strategies have arose with the desire for increasing the chemical complexity of the interior and exterior. Accelerated growth of larger generations with fewer synthetic steps, simplification of purification, and new methods for end-group functionalization have drawn much interest in the dendrimer field as well as providing potential for their use in a variety of materials applications. Herein, methodologies for forming a library of complex dendrimer architectures are described in order for a better understanding of the possible structure property landscape, which is added to by both physical experimentation and computational simulation.;The physical goal was to design and synthesize two isomeric dendrimer architectures using the AB2 type polyester branching unit, 2,2-bis(hydroxymethyl)propionic acid (bisMPA). The two architectures were synthesized modularly using a hybrid growth approach involving the divergent synthesis of dendrons and coupling of their core functionalities with the copper(I) catalyzed Azide-Alkyne Cycloaddition (CuAAC). Two "Click"-type reactive moieties, based upon CuAAC and radical Thiol-Ene coupling reactions, were attached to the termini of dendrimers. By attaching the two highly efficient reactive groups, either homogenously on the dendrimer periphery or isolated to individual dendrons, we have developed a small library of functional scaffolds capable of being used to produce a vast array of macromolecules with various properties.;The computational goal was to understand the differences associated with the two dendrimer architectures when linear polymer chains were attached to the dendrimer periphery. Simulations using coarse-grained Brownian Dynamics methods were studied with varied generation size of the dendrimers, and thus functional group number on the periphery. The molecular architecture, polymer chain length, and differences in chemical potentials between the polymer chains could be varied to yield information on the unimolecular structure of these macromolecules in a dilute solution. |
