Structural characterization and molecular dynamics in the solid-state in Poly(ethyleneimine) polymers

J. M. LÁZARO MARTÍNEZ; A. K. CHATTAH; G. A. MONTI

Río de Janeiro

Congreso; 18th International Society of Magnetic Resonance Meeting; 2013

ISMAR

The linear polymer poly(ethyleneimine) (PEI) has a wide field of applications. It has been used as a cosmetic ingredient to adjust viscosity, as chelating metal ions to inhibit corrosion, and as copolymer to develop energy storage devices. Interestingly, taking into account the biocompatibility of the PEI, it has been used in biotechnology as non-viral vector to carry out gene transfection processes. However, no physical characterization in the solid state has been done. Therefore, the objective of this work is to study the structural and dynamic homogeneity in three synthetic variants of PEI with different molecular weights (22, 87 and 217 kDa) through Nuclear Magnetic Resonance techniques in the solid state (SSNMR). In addition, changes will be explored after the uptake of copper ion (II) by these polymeric matrices, given the importance of the heterogeneous catalysts of Cu(II) for the activation of hydrogen peroxide and degradation of pollutants with high environmental impact (Lazaro Martinez, et al., 2008 and 2011). The SSNMR proved to be a valuable tool for studying the dynamics and homogeneity of the different samples of PEI. However the results of X-ray powder crystallography do not show significant differences between different samples. SSNMR through 13C CP-MAS spectra using different spin time dynamics enabled to demonstrate the heterogeneity in each case, as well as 15N CP-MAS spectra. These results were confirmed by measuring T113C, 1H-13C 2D-WISE and 1H-13C 2D-HETCOR. Finally, the formation of complexes with copper ions (II) produced a significant reduction in the molecular mobility as a result of crosslinking between the different polymer chains to coordinate the metal ion, based on the results of T113C and 1H-13C 2D-WISE.