Divergent synthesis and self-assembly of amphiphilic polymeric dendrons with selective degradable linkages

Enhancing the structural complexity and functionality of the building blocks allows the construction of supramolecular assemblies. In this work, we demonstrate a strategy for the design and synthesis of complex macromolecular architectures. We use atom transfer radical polymerization to produce well-defined polymers with telechelic end-group functionality, and "click" them together to form functional 3rd generation dendrons, and incorporated degradable linkages and certain functionality at the polymer chain-ends of each generation. The 3rd generation polymeric dendrons consisted of homopolymer polystyrene (PSTY) with either four solketals or eight alcohols, diblock PSTY and poly(t-butyl acrylate), and amphiphilic diblock. The peripheral ends consisting of alcohols create functionalization points for further chemical modification or chemical coupling and the cleavable linkages between the 2nd and 3rd generations all provide the first steps toward smart nanostructures. Importantly, we can synthesize these dendrons in pure form. The self-assembly of the amphiphilic dendrons (the inner and outer generations consisting of PSTY and polyacrylic acid, respectively) in water produced micelles of uniform size with an aggregation number of 43 dendrons per micelle. The size of the micelles was small (D-H = 20.7 nm) and comparable to the size found by transmission electron microscopy (14-18 nm). (C) 2008 Wiley Periodicals, Inc.