Polymeric Nanoparticles via Noncovalent Cross-Linking of Linear Chains

Novel polymeric nanoparticles were prepared through the chain collapse of linear polymers driven by noncovalent cross-linking of dendritic self-complementary hydrogen-bonding units (SHB). Random copolymers containing SHB units, poly[(methyl methacrylate)- r -2-((3,5-bis(4-carbamoyl-3-(trifluoromethyl)phenoxy)benzyloxy)carbonylamino)ethyl methacrylate] ( A1, A2 ), were synthesized with various incorporation ratios by reversible addition−fragmentation chain transfer (RAFT) polymerization. Dramatically different behavior was observed depending on the level of incorporation of the supramolecular units. At high loadings of A2 (6% SHB incorporation), intramolecular chain collapse is favored, resulting in the formation of well-defined polymer nanoparticles, which were characterized by scanning force microscopy (SFM), dynamic light scattering (DLS), and viscosity studies. In contrast, analysis of copolymer A1 (1% SHB incorporation) revealed that chain collapse occurred primarily through intermolecular interactions leading to large aggregates.