A new sulfonated poly(aromatic imide-co-aliphatic imide) (SPI) for the use as a polymer electrolyte membrane was successfully synthesized from 4,4'-diaminodiphenylmethane (DDM), 4,4'-diaminodiphenylmethane-2,2'-disulfonic acid disodium salt (S-DDM), hexamethylenediamine, and 3,3',4,4'-benzophenonetetracarboxylic dianhydride in a one-step reaction. S-DDM was prepared by the direct sulfonation of DDM monomer. The degree of sulfonation of the sulfonated copolyimide was varied by using various molar concentrations of S-DDM. The sulfonated copolyimide with the highest degree of sulfonation possessed the proton conductivity of 0.0032 S.cm-1 in a wet state. The highest methanol permeability of the sulfonated copolyimide was 2.75 × 10-8 cm2.s-1 which is ~425 times lower than that of the Nafion 117. The highest membrane selectivity belonged to the membrane with 34% degree of sulfonation with the value of 1.65 × 106 s.S.cm-3 which is three orders of magnitude higher than the commercial Nafion 117.

Poly(2,5-dimethoxyaniline) (PDMA) was synthesized using electrochemical polymerization of DMA in oxalic acid. The PDMA film coated onto ITO glass was studied for its chemical structure, morphology, electro-deposition, and electro-activity by FT-IR, TGA, SEM, cyclic voltammetry, and UV-Vis spectrophotometry. The PDMA film showed reversible color changes from yellow to blue representing the transition between the fully reduced state to the fully oxidized state upon switching the potentials. The response time of the PDMA film in term of color change was investigated under various applied potentials and different types of acid electrolyte (HCl and H2SO4). The fast response time of less than 2 sec was observed at the applied potential of 1.6 V. In comparison with HCl, the use of H2SO4 as an electrolyte resulted in the fastest response time. Thus, the PDMA is a potential candidate in electrochromic devices due to its reversible color change and fast response time.