Exploiting Self-Healing Characteristics of Poly(methyl methacrylate) in Gel Electrolyte for Application in Electrochromic Devices

Abstract

Self-healing characteristics in a gel electrolyte (GE) are desirable to improve the optical performance and service life of an electrochromic device (ECD). By exploiting the healing properties of poly(methyl methacrylate) (PMMA), the fabrication and characterization of GE with self-healing capabilities are reported here. Comparative mechanical and electrochemical analyses of the original and healed GE samples are performed to determine the optimum PMMA concentration and healing time. Experimental results show that the GE with 15 wt % of PMMA (GE15) recovers 98% of its mechanical strength within 10 min of healing time. The ionic conductivities of the healed samples are found to be the same as that of the original sample at all PMMA concentrations and healing times. It is observed that the healing time, viscosity, number of uncoiling polymer chains, and mobility of Li+ ions critically influence the healing efficiency of a GE. Color contrast analyses of ECDs fabricated with original and healed GEs are performed to demonstrate the applicability of self-healable GEs. It is recorded that for longer healing times the color performances of self-healed ECDs approach that of the original ECD. The findings of the present study will help to develop repair strategies for ECDs and improve their service life.