(693a) Block Copolymer Bottlebrushes: New Routes to Ever Smaller Microdomain Sizes

Block copolymer self-assembly at the nanoscale presents tremendous opportunities for the development of new nanotemplates for advanced lithography applications, wherein the homopolymer-rich microdomain sizes (~ 10–100 nm) are governed by the total copolymer degree of polymerization, N. However, this methodology is limited in its smallest achievable length scale, since AB diblock copolymers self–assemble only above a critical N that depends inversely on the magnitude of the interaction parameter χ_AB, which quantifies the energetic repulsions between the dissimilar homopolymer segments. Numerous recent reports have focused on developing “high χ_AB” AB diblocks that self–assemble at low values of N. In this talk we explore the ability of non-linear polymer architectures to induce block copolymer ordering at reduced length scales. Thus, we describe the melt and thin film self-assembly behavior of block copolymer bottlebrushes derived from linking the block junctions of low molecular weight AB diblocks. We quantitatively demonstrate that increasing the bottlebrush backbone degree of polymerization (N_backbone) results in as much as a 75% reduction in the critical copolymer arm degree of polymerization (N_arm) required for self-assembly, thus reducing the length scales at which these materials self-assemble.