The relationship between the monomer precision and complex functions inherent in biologically-derived macromolecules has inspired rapid advances in strategies to produce precisely defined sequences in synthetic polymers. While synthetic sequence control has not reached the level of most biomacromolecules, many diverse sequences are now available on a limited scale. Together with continued progress toward better sequence-control, it is now necessary to address scalability and further investigate the influence of sequence on polymer properties.<br/><br/>We have synthesized a series of sequence-defined polyurethane oligomers (12-mers, ~1400 g/mol) derived from a sustainable monomer, vanillin, via sequential reductive amination and amidation reactions. High conversions and recovered yields of each reaction as well as a cheap, renewable monomer source allow the production of these sequence-defined oligomers on a gram scale suitable for investigation of mechanical properties. Purification steps are also carried out without the need for costly, time-consuming, and unsustainable techniques like column chromatography. The amine monomers used in the reductive amination step provide access to sequence-specific, functional pendant groups. Due to the rigid backbone nature of these oligomers, their conformation in solution with respect to sequence has been investigated with 2D NMR spectroscopy. Thermomechanical properties have also been studied and the influence of sequence on cross-linking via sequence-specific, reactive pendant groups has been explored.<br/><br/>This work is one of the few examples where sequence-defined oligomers can be synthesized on a gram scale, facilitating the investigation of sequence-dependent bulk material properties. Moreover, additional sequences can now be explored and their applications expanded. It is expected that this work will provide the foundation for future studies targeting the tunability of material properties via sequence control.

Sequence-controlled polyurethane networks

256th National Meeting (2018)

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