The sequence specificity of a class of biologically inspired polymers based on N-substituted alywnes (polypeptolds) allows for a degree of tunability in the ci ystallization and thermal behavioi not available in classical polymw systems It is demonstrated that a sei les of peptoid homopolymers are stable up to temperatures of 250-300 degrees C and are crystalline with reversible melting transitions ranging from 150 to 225 degrees C Defects inserted at precise locations along the polymer backbone (as monomer substitutions) enable control of the melting temperatuie Melting points dew ease with mei eased defect content, and X-ray diffrw:tion (X RD) indicates defect inclusion in the et ystal lattice In addition, it is demonstrated that the distribution of the defects foi a given content level affects the thermal propel ties of the peptold chain