Complete photonic band gaps with nonfrustrated ABC bottlebrush copolymers

Block polymers are a promising platform for photonic materials, yet progress has been limited due to the scarcity of suitable morphologies with complete photonic band gaps and the large domain sizes necessary to manipulate visible light. Here we show that nonfrustrated ABC bottlebrush copolymers can surmount both of these limitations and can be used to form materials with complete photonic band gaps. To achieve this, we have developed a computational tool that couples self-consistent field theory (SCFT) simulations to Maxwell's equations, thereby permitting a direct link between molecular design, self-assembly and the resulting photonic band structure. Using this approach, we calculate the phase diagram of ABC bottlebrush copolymers, and show that complete photonic band gaps can open in the alternating gyroid and alternating diamond phases for modest dielectric contrast between the A, B, and C components. We show that the gap width increases with segregation strength, and depends strongly of the volume fractions of the A and C networks. Notably, the maximum band gap for the alternating gyroid corresponds to a region of the bottlebrush phase diagram where SCFT predicts this phase to be stable, suggesting that these photonic materials could be realized experimentally.