Design and Synthesis of Network-Forming Triblock Copolymers Using Tapered Block Interfaces

We report a strategy for generating novel dual-tapered poly­(isoprene-<i>b</i>-isoprene/styrene-<i>b</i>-styrene-<i>b</i>-styrene/methyl methacrylate-<i>b</i>-methyl methacrylate) [P­(I-IS-S-SM-M)] triblock copolymers that combines anionic polymerization, atom transfer radical polymerization (ATRP), and Huisgen 1,3-dipolar cycloaddition click chemistry. The tapered interfaces between blocks were synthesized via a semibatch feed using programmable syringe pumps. This strategy allowed us to manipulate the transition region between copolymer blocks in triblock copolymers, providing control over the interfacial interactions in our nanoscale phase-separated materials independent of molecular weight and block constituents. Additionally, we show the ability to retain a desirous and complex multiply continuous network structure (alternating gyroid) in our dual-tapered triblock material

Inducing Order from Disordered Copolymers: On Demand Generation of Triblock Morphologies Including Networks

Disordered block copolymers are generally impractical in nanopatterning applications due to their inability to self-assemble into well-defined nanostructures. However, inducing order in low molecular weight disordered systems permits the design of periodic structures with smaller characteristic sizes. Here, we have induced nanoscale phase separation from disordered triblock copolymer melts to form well-ordered lamellae, hexagonally packed cylinders, and a triply periodic gyroid network structure, using a copolymer/homopolymer blending approach, which incorporates constituent homopolymers into selective block domains. This versatile blending approach allows one to precisely target multiple nanostructures from a single disordered material and can be applied to a wide variety of triblock copolymer systems for nanotemplating and nanoscale separation applications requiring nanoscale feature sizes and/or high areal feature densities