Aiming to develop pH-paper-like current sensing materials, we prepared irreversible electrochromic PDA-PMMA/graphene composites. The composites exhibited an excellent linear relationship between critical responsive currents and the amount of graphene in the system. In these composites, PDA acted as the electrochromic material and graphene as the conductive matrix. The presence of PMMA not only ensured mechanical performance but also made the color change more obvious to be observed by the naked eye.
