Precision Synthesis of Living Anionic Polymer Cross-Linked Nanorods in Concentrated Solutions

One-dimensional polymeric nanostructures provide a versatile platform to construct multifunctional materials. The conventional grafting-from approach toward bottlebrushes and derivative nanorods is compromised by inefficient initiation, heterogeneous propagation, incomplete conversion, and uncontrolled intermolecular cross-linking. Herein, we propose a difunctional asymmetric monomer assisted orthogonal living anionic grafting-from method to precisely synthesize polymer bottlebrushes and nanorods in concentrated solutions. The polymer backbone is achieved by selective anionic polymerization of methacrylate group at the 1,1-diphenylethylene (DPE)-methacrylate monomer, while the pendant DPE groups could be further initiated quantitatively to grow side chains via living anionic copolymerization of methacrylates and the vinylphenyl-methacrylate asymmetric monomer (StMA). The pendant vinylphenyl groups could be initiated for polymerization of styrenic monomers, which could be selectively terminated with alkyl chlorides. Under the inherent electrostatic mediation from the anionic methacrylate enolates at the growth frontier, the cross-linking within the layer via copolymerization of cross-linker contained styrenic monomers is allowed to achieve living cross-linked nanorod in concentrated solutions. The orthogonal living anionic grafting-from method could be iterative in one pot to achieve multilayered bottlebrushes or nanorods. Similarly, the Janus nanorods bearing distinct groups at the opposite blocks are derived from the triblock terpolymers. Various components and functions are distinctly compartmentalized within desired regions.