As the complexity of polymer structure grows, so do the challenges for developing an accurate understanding of their structure–property relationships. Here, the synthesis of bottlebrush polymers with topologically precise and fully discrete structures is reported. A key feature of the strategy is the synthesis of discrete macromonomer libraries for their polymerization into topologically precise bottlebrushes that can be separated into discrete bottlebrushes ( Đ = 1.0). As the system becomes more discrete, packing efficiency increases, distinct three-phase Langmuir−Blodgett isotherms are observed, and its glass transition temperature becomes responsive to side-chain sequence. Overall, this work presents a versatile strategy to access a range of precision bottlebrush polymers and unravels the impact of side-chain topology on their macroscopic properties. Precise control over side chains opens a pathway for tailoring polymer properties without changing their chemical makeup.

The synthesis of bottlebrush polymers with discrete side chains, their surface pressure isotherm measurements, and thin film molecular dynamics simulations are reported. Our results show that monolayers of bottlebrushes with discrete side chains achieve higher packing densities and exhibit previously unknown, distinct phase transitions that are unseen in their disperse counterparts. The combination of experimental findings and simulation results show that shape‐defined bottlebrush polymers can advance structure–property relationship studies of branched polymers and the theoretical descriptions of polymer monolayer self‐assembly.

The glass transition of branched polymers is determined by multiple structural parameters that dictate their inter- and intramolecular interactions, and ultimately, their molecular packing in the amorphous phase. Here we...

The synthesis of bottlebrush polymers with topologically precise and fully discrete structures is reported. Key features of the synthesis include the combination of scalable synthesis and separation strategies to access discrete macromonomer libraries, followed by their polymerization and further separation into topologically uniform and discrete bottlebrushes. Discrete macromonomers prove crucial for regulating the structural heterogeneity of bottlebrushes and their macroscopic properties. When assembled as a monolayer at the air-water interface, bottlebrushes with discrete side chains display high packing density and distinct three-phase Langmuir-Blodgett isotherms. The impact of precisely regulating side chain dispersity and sequence on polymer properties was further demonstrated through tailoring the interbrush interactions and thermomechanical properties of well-defined block bottlebrushes.

The glass transition of branched polymers is determined by multiple structural parameters that dictate their inter- and intramolecular interactions, and ultimately, their molecular packing in the amorphous phase. Here we examined the impact of side chain length, backbone length, molecular weight composition, and topology on the glass transition behavior of bottlebrush polymers. Through examining precision bottlebrush polymer libraries (PBP, ĐSC = 1.0), we find the infinite molecular weight Tg is reached at a specific brush length after which the effect of the side-chain length dominates. Being a factor more dominant than the backbone, side-chain length affects the Tg of bottlebrush polymers across all sizes and topology variations. To demonstrate the versatility of side chain engineering strategies, a broad range of Tg and glass transition behavior was targeted through judicious choice of side chain length, blend ratios, and brush topology.