Derivative of iota-carrageenan as solid polymer electrolyte
A new type of solid polymer electrolyte based on iota (ɩ)-carrageenan derivative has been investigated. ɩ-Carrageenan was reacted with monochloroacetic acid to produce carboxymethyl ɩ-carrageenan. The produced powders were characterized by 1H nuclear magnetic resonance and attenuated total reflection Fourier transform infrared spectroscopy to confirm the substitution of targeted functional in ɩ-carrageenan. The polymer electrolytes films were prepared by solution casting technique. Thermal gravimetric analysis result shows that the modified powder and film were stable up to 300 °C. X-ray diffraction analysis shows that the chemical modification of ɩ-carrageenan increases the amorphous phase of polymer electrolyte film. Meanwhile, the scanning electron microscope observation reveals that the carboxymethyl ɩ-carrageenan film becomes smoother than ɩ-carrageenan film which supports the ionic conductivity enhancement. The ionic conductivity of ɩ-carrageenan film increases from 2.19 × 10−8 to 4.87 × 10−6 S cm−1 after chemical modification of ɩ-carrageenan to carboxymethyl ɩ-carrageenan.