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Synthesis and characterization of poly-l-leucine initialized and immobilized by rehydrated hydrotalcite: Understanding stability and the nature of interaction
Miranda, Ronald Alexander; Finocchio, Elisabetta; Llorca Piqué, Jordi; Medina, Francisco; Ramis, Gianguido; Sueiras, Jesus Eduardo; Segarra, A.M.
Universitat Politècnica de Catalunya. Institut de Tècniques Energètiques; Universitat Politècnica de Catalunya. GREENER - Grup de recerca d´estudis energètics i de les radiacions
PLLs were synthesized by the ring-opening polycondensation (ROP) method using α-L-leucine N-carboxyanhydride (NCA) and initialized by triethylamine (Et3N), water or rehydrated hydrotalcite (HTrus). The role of temperature, different initiators and water in ROP was further investigated. In general, the initiators used in the polymerization reaction lead to PLL alpha-helical chains containing 5–40 monomers with NCA endgroups via a monomer-activated mechanism. However, the water has a twofold effect on ROP, as both a nucleophile and a base, which involves competition between two different types of initiating mechanisms (nucleophilic attack or deprotonation of the NCA monomer) in the polymerization reaction. This competition provides as a main product NCA endgroups with an alpha-helical structure and leads to the formation of the PLL cyclic-chains and beta-sheet structures which reduce the polymer Mw and the PD of the polypeptide. Furthermore, the water can hydrolyze the NCA endgroups resulting in PLL alpha-helical chains that contain living groups as the main product. On the other hand, the HTrus presents a double role: as both an initiator and a support. The polymers synthesized in the presence of HTrus presented a HT-carboxylate endgroup. The PLLs immobilized in HTrus through an anion-exchange method performed for just 30 minutes presented the PLL immobilized in the interlayer space of the HTrus. The PLL chains of the immobilized counterpart are stabilized by H-bonding with the M–OH of the HT structure. All the polypeptides and biohybrid materials synthesized have been characterized using different techniques (EA, ICP, XRD, Raman, MALDI-TOF, ESI-TOF, FT-IR at increasing temperatures, TG/DT analyses and TEM).
Àrees temàtiques de la UPC::Enginyeria química::Química física
Àrees temàtiques de la UPC::Enginyeria dels materials::Materials plàstics i polímers
Polimerització -- Síntesi
Attribution-NonCommercial-NoDerivs 3.0 Spain

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