Janus Composite Nanorod from a Molecular Bottlebrush Containing a Block Copolymer.

The asymmetric ABC-type Janus polymer composite nanorods are synthesized by the in situ preferential growth of functional materials against the molecular bottlebrush containing a triblock copolymer of poly(ethylene oxide)-b-poly(2-methacryloyloxyethyl pentynoate-g-poly(acrylic acid))-b-polystyrene. PEO and PS single chains are terminated onto the opposite ends of the composite nanorods. The two polymer chains are responsible for amphiphilic performance, while the composite nanorod is responsible for the functionality. The Janus nanorods can stand vertically at an emulsion interface, making the interfaces easily functionalized and manipulated. Protection of the PAA molecular bottlebrush via electrostatic interaction is important to obtaining individual nanorods at high solid contents. A huge family of Janus composite nanorods is expected by changing the compositions of the two polymer chains and the nanorod.