Selective localization of lithium perchlorate in immiscible blends of poly(ethylene oxide) and epoxidized natural rubber

Immiscible blends of poly(ethylene oxide) (PEO) and epoxidized natural rubber (ENR) comprising of lithium perchlorate (LiClO4) were prepared by solution casting method. Blends of PEO and ENR are found to be thermodynamically immiscible via thermal analysis and the result has been reported previously. It is also noted in the previous study that LiClO4 dissolves preferentially in PEO than in ENR. Fourier-transform infrared (FTIR) spectroscopic studies on the blends of PEO/ENR and PEO/ENR/LiClO4 at all compositions in this work aim at investigating the ion-dipole interactions between the Li⁺ ions and the polymer components of the PEO/ENR/LiClO4 blends from a different approach so as to verify the selective localization of the salt in the different phases of the blends. FTIR results show that Li⁺ ions coordinate individually to the neat polymers of the PEO/ENR/LiClO4 blends at the ether oxygen of PEO and the oxirane group of ENR. Spectroscopic studies reveal again the preferential solubility of the salt in PEO.