Systematic Order-Made Synthesis of Sequence-Defined Polyurethanes with Length, Types, and Topologies.

Polyurethanes are industrially and academically important as soft materials. They are conventionally synthesized by a process based on step-growth polymerization; thus, molecular weight and structural control are impossible. However, the development of a synthetic strategy for polyurethanes remains a big challenge in designing soft materials. Herein, we demonstrate a synthetic methodology for generating polyurethanes with selectable lengths and termini characteristics. The multistep synthetic process offered the systematic synthesis of high-molecular weight, regioregular, and α,ω-urethane telechelics. Various oligomers with order-made repeating units revealed the effective length of the polymer properties. To demonstrate the scope of our methodology, it was also applied to the synthesis of block co-oligomers, three-armed star oligomers, and miktoarm star co-oligomers. Thus, our method allows the synthesis of high-molecular-weight oligomers with complete structural and molecular weight control, which is of enormous value to materials science; particularly the study and application of structure-property relationships in polyurethanes.