STIR: A Pilot Study on the Bulk Properties and Morphology of Polypeptide-Grafted Brush Polymers.

摘要

Incorporating synthetic polypeptides with intrinsic secondary structures into side chains of brush-like polymers may facilitate interesting physical properties of these materials, as the entanglement and association behaviors of the polypeptide chains significantly differ from those of flexible polymer coils. This pilot study aimed to correlate the physical properties of polypeptide-grafted brush polymers with the structure and the interactions of grafted polypeptide chains. In the 9-month project, we have synthesized a small library of brush polymers with grafted polypeptides of specific compositions and molecular weights, by integrating ring-opening metathesis polymerization (ROMP) and ring-opening polymerization of amino acid N-carboxyanhyrides (NCA). The structures and association behaviors of the grafted polypeptide chains in these brush polymers have been characterized by FTIR, NMR and X-ray scattering methods and correlated with the architecture of the macromolecules. We found that grafted polypeptides with long helical structures facilitate the intermolecular association of the brush-like polymers, and allow for the formation of robust films in which the molecular orientation can be induced by mechanical stretching or thermal annealing. The molecular nature of the entanglement behaviors found in these unique brush polymers may be further elucidated by studying the viscoelastic properties of these materials.