Studies on the plasticization efficiency of deep eutectic solvent in suppressing the crystallinity of corn starch based polymer electrolytes

A series of polymer electrolytes composed of corn starch (CS), lithium bis(trifluoromethanesulfonyl)imide (LITFSI) and deep eutectic solvent (DES) were fabricated by solution casting technique. The DES was synthesized from a mixture of choline chloride and urea at a molar ratio of 1:2. The addition of DES is crucial in enhancing the room temperature ionic conductivity by increasing the amorphous elastomeric phase in CS:LITFSI matrix. The ionic transport mechanism is improved and appreciable amount of ion conducting polymer electrolytes is produced. The highest ionic conductivity achieved for the polymer electrolyte composition CS: [SITS!: DES (14 wt.%:6 wt.%:80 wt.%) is 1.04 x 10(-3) S cm(-1). The anomalies that were observed with the addition of DES upon formation of neutral ion multiples were visually revealed by the SEM micrographs. The possible dipole-dipole interaction between the constituents was visualized by the FTIR spectroscopy upon change in cage peaks. (C) 2011 Elsevier Ltd. All rights reserved.