Control of Crystallization and Melting Behavior in Sequence Specific Polypeptoids

Abstract

The sequence specificity of a class of biologically inspired polymers based on N-substituted glycines (polypeptoids) allows for a degree of tunability in the crystallization and thermal behavior not available in classical polymer systems. It is demonstrated that a series of peptoid homopolymers are stable up to temperatures of 250−300 °C and are crystalline with reversible melting transitions ranging from 150 to 225 °C. Defects inserted at precise locations along the polymer backbone (as monomer substitutions) enable control of the melting temperature. Melting points decrease with increased defect content, and X-ray diffraction (XRD) indicates defect inclusion in the crystal lattice. In addition, it is demonstrated that the distribution of the defects for a given content level affects the thermal properties of the peptoid chain.