Aramids containing dicyanotriphenylamine skeleton in the polymer backbone were prepared and applied as anode materials for organic lithium-ion batteries.
A facile approach was employed to produce thermosets of styrene-maleic anhydride copolymers (SMA) containing three kinds of triarylamine moieties to elucidate electrochromic (EC) behaviors comprehensively, and an additional ionization modification was also applied to explore the effect on counterion diffusion kinetics during the electrochemical process. The commercially available SMA was chosen as the starting material for coupling with three triarylamine-based diamine monomers, 4,4′-diamino-4″-methoxytriphenylamine (3Ph), N,N′-bis(4-aminophenyl)-N,N′-di(4-methoxylphenyl)-1,4-phenylenediamine (5Ph), and 4,4′-bis[4-aminophenyl(4-methoxyphenyl)amino)]-4″-methoxytriphenylamine (7Ph), resulting in colorless and transparent thermoset polymer films with different interchain distances. Furthermore, the precursors of these polyamic acids could be reacted with triethylamine (Et3N) to form the related triethylammonium-containing PAA complexes, which could facilitate the migration of counterion during redox procedures. After evaluating the electrochemical and EC behaviors, we demonstrate that the merge of enlarging interchain distance and ionization modifications in the triarylamine-coupling SMA copolymer matrixes leads to synergistic effects in the diffusion dynamics of the electrolyte counterion and could effectively enhance higher diffusion rates (D) of the counterion in the polymer matrix with more than 2,400 times larger (iS5Ph: 96.73 cm2 s–110–18) than the triphenylamine-based linear type polyimide, L3Ph (0.04 cm2 s–110–18), and the prepared electrochromic device (ECD) properties revealed faster coloration response speed (υc) 43.7% s–1 and outstanding coloration efficiency (ηCE) up to 540 cm2/C.
A new triphenylamine-containing aromatic diamine, N,N-bis(4-aminophenyl)-N',N'-di(4-methoxylphenyl)-1,4-phenylenediamine (4), was successfully synthesized by the cesium fluoride-mediated condensation of 4-amino-4',4' '-dimethoxytriphenylamine with 4-fluoronitrobenzene, followed by palladium-catalyzed hydrazine reduction of the dinitro intermediate. A series of novel polyamides with pendent 4,4'-dimethoxy-substituted triphenylamine (TPA) units having inherent viscosities of 0.28−0.80 dL/g were prepared via the direct phosphorylation polycondensation from the diamine (4) and various dicarboxylic acids. All the polymers were amorphous with good solubility in many organic solvents, such as N-methyl-2-pyrrolidinone (NMP) and N,N-dimethylacetamide (DMAc), and could be solution-cast into tough and flexible polymer films. These aromatic polyamides had useful levels of thermal stability associated with their relatively high softening temperature (242−282 °C), 10% weight-loss temperatures in excess of 510 °C, and char yields at 800 °C in nitrogen higher than 63%. The hole-transporting and electrochromic properties are examined by electrochemical and spectroelectrochemical methods. Cyclic voltammograms of the polyamide films cast onto an indium−tin oxide (ITO) coated glass substrate exhibited two reversible oxidation redox couples at 0.47−0.51 and 0.82−0.86 V vs Ag/AgCl in acetonitrile solution. The polyamide films revealed excellent stability of electrochromic characteristics, with a color change from colorless or pale yellowish neutral form to green and blue oxidized form at applied potentials ranging from 0.00 to 0.98 V. These anodically polymeric electrochromic materials not only showed excellent reversible electrochromic stability with good coloration efficiency of green (CE = 285 cm2/C) and blue (CE = 272 cm2/C) but also exhibited high contrast of optical transmittance change (ΔT %) up to 60% at 430 nm and 73% at 1035 nm for green, and 86% at 850 nm for blue. After over 1000 cyclic switches, the polymer films still exhibited excellent stability of electrochromic characteristics.
New luminescent and electrochromic polyimidothioethers were synthesized and fabricated as ambipolar electrochromic and electrofluorochromic devices, and fluorescent electrospun fibers.
Abstract Silver (Ag) nanoparticle has extremely high surface energy and it is difficult to find an efficient dispersant to prevent its agglomeration in suspensions. A new brush copolymer, succinic anhydride modified epoxy‐amine poly[(propylene oxide)‐ co ‐(ethylene oxide)]‐grafted polymer (EPOA), which can efficiently disperse concentrated aqueous suspensions of Ag nanoparticles is revealed. The dispersion efficiency of EPOA for the dispersion of a 60 nm‐Ag nanoparticles in aqueous suspension is studied by measuring its sedimentation and rheological behavior, and the results are compared with those of a commercially available dispersant, ammonium poly(acrylic acid) (PAA‐NH 4 ). Interactions between the dispersants and the Ag nanoparticles are characterized by zeta potential and adsorption analyses. Theoretical calculations are conducted to clarify the adsorption and the dominant dispersion stabilization mechanisms of the dispersants. Compared with PAA‐NH 4 , EPOA obtains a higher stable suspension of Ag nanoparticles with less significant sedimentation over 1 month. The dispersion homogeneity of the suspension remains excellent even at an extremely high solid loading of 30–40 wt%. According to adsorption analysis, it is suggested that both EPOA and PAA‐NH 4 adsorb via single‐point attachment through the carboxyl group on the Ag surface. Based on theoretical calculations, the Ag nanoparticles are better stabilized by EPOA via an electrosteric dispersion mechanism.
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