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A.C. conductivity and nuclear magnetic resonance study of structural and dynamics properties of polymer electrolytes on base natural polymer

Abstract

The natural polymers, as chitosan, agar, gelatin, starch, cellulose derivatives, casein, pectin, have been drawing attention because of its specific properties, such as biodegrability, low cost and good physical and chemical properties. Actually, the A.C. conductivity and nuclear magnetic resonance (NMR) are of great significance for solid state ionics characterization. This work report the A.C. conductivity and NMR study of the physical and chemical properties of films base on natural polymer. The A.C. conductivity measurements by complex impedance will provide the value for ionic conductivity. The NMR measurements in the time domain (NMR-TD) by saturation-recovery and CPMG (Carr - Purcel - Meiboom - Gill) pulse sequences will provide the 1H spin-lattice (T1) and spin-spin (T2) relaxation times, respectively. Due to structural complexity found in these natural polymers, the magnetization decay obtained from NMR experiments usually shows a multi-exponentials form that could be interpreted by a continuous distribution of relaxation times. Data analysis will be performed using the NNLS algorithm (Non-Negative Leat Square) in order to obtain information about structural and molecular mobility of proton in these materials. The studies of pulsed gradient stimulated echo NMR (PGSTE) will allow the quantification of the molecular diffusion by the evolution of echo amplitude decay. (AU)

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VEICULO: TITULO (DATA)
VEICULO: TITULO (DATA)