Hybrid Polymers Bearing Mono/Oligo‐L‐Lysine(Z)s: ADMET Polymerization and Structural Investigations in the Solid State

Abstract Advancing novel polymers for biomedical applications requires in‐depth knowledge between their chemical structure and physical properties under conditions such as assembly or folding. The secondary structure of hybrid‐polymers containing lysine‐residues (Lys) inside their main chain, separated by a stretch of n‐alkyl‐chains is here investigated. The polymer (A‐[Lys n = 1 ] m = 18 ) is prepared by ADMET polymerization of the bis‐ω‐ene‐functional mono‐L‐lysine(Z)s (Lys n = 1 ) optimizing conditions for ADMET polymerization of Lys n = 1 monomers in bulk. The hybrid‐polymers, A‐[Lys n = 1 ] m = 3, 7, 9, 18, 44 with molecular weights ranging from 1.3 to 17.6 kDa, display polydispersity (Đ) values in the range of 1.3–2.6. Comparison between these polymers and previously reported hybrid ADMET polymer, oligo‐L‐lysine(carboxybenzyl(Z)), (A‐[Lys n ] m ) (i.e., n = 4, m = 24), containing longer stretches of the embedded lysine‐unit was accomplished. Solid‐state investigations (FT‐IR and DSC) of the hybrid‐polymers, A‐[Lys n = 1 ] m = 18 , A‐[Lys n = 12 ] m = 8, and A‐[Lys n = 24 ] m = 4 , and the pre‐polymers, Lys n = 12 and Lys n = 24 proved the presence of α‐helices and β‐folds at elevated temperatures in the range of 20 to 200 °C, further gaining understanding of the influence of the chain length of polymers on the formation of secondary structures.