ATR-FTIR and NMR Spectroscopic Studies on The Structure of Polymeric Gel Electrolytes for Biomedical Applications

The structure of polymeric gel membranes to be used as electrolytes in the recording of bioelectrical signals has been investigated by means of ATR-FTIR and Li-7 and C-13 MAS NMR spectroscopies. The membranes, based on PMMA, 1,2-diethoxyethane and lithium perchlorate, showed different ionic conductivity as a function of their composition. Such differences have been analyzed on the basis of spectroscopic data and the existence of interactions with the ester function in the polymeric matrix was determined. Spectroscopic data allowed to establish the optimal lithium concentration needed to achieve best ionic conductivity.