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.

Composites of polydiphenylamine (D-PDPA) and zeolite Y with H+ as the cation (Y_H+) have been fabricated to be used as a sensing material towards non-halogenated and halogenated solvents (hexane, dichloromethane, 1, 2-dichloroethane, chloroform). These composites are toxic towards human and environment and are widely used as solvents in various industries. Polydiphenylamine, zeolite Y, and their composites are characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, particle size analysis, surface area, and pore size analysis. The effects of the Si/Al ratio, zeolite content, and vapor concentrations are investigated. The electrical conductivity sensitivity of the composites towards the solvents is higher than the pristine D-PDPA by ~1 order of magnitude. The composites can discriminate a non-halogenated solvent from halogenated solvents. They possess maximum electrical conductivity sensitivity values towards dichloromethane, but the composites do not respond to hexane. Generally, the sensitivity of the composites increases with increasing zeolite content and vapor concentration. The interactions between the composites and the vapors are investigated by FT-IR spectroscopy and UV-Vis spectroscopy. A mechanism for the interaction between the composites and the solvents is proposed.