Metallo-polyelectrolytes have been demonstrated to be promising candidates for anion exchange membranes (AEMs) due to their excellent alkaline stability. Here, cobaltoceniumcontaining metallo-polyelectrolyte-based AEMs with good chemical stability and dimensional stability were prepared through facile acetalation of a commodity polymer, poly(vinyl alcohol). The AEM crosslinked with 1 wt % glutaraldehyde (GA) exhibits a comparable hydroxide conductivity of 72 mS/cm at 80 °C and enhanced alkaline stability in 1 M NaOH at 80 °C (maintained 86.3% of initial hydroxide conductivity after 1000 h). The dimensional stability of these AEMs can be tuned through acetalation crosslinking with GA, and the swelling ratio of 1% GA was 17.8% and the gel fraction was 90.5%. The H 2 /O 2 single cell using 1% GA AEM (50 μm, Fumion ionomer) showed a maximum power density of 120 mW/cm 2 at 60 °C without backpressure. This work provides a facile method for the preparation of stable metallo-polyelectrolyte-based alkaline membrane fuel cells.

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We design two novel solution processable polyimides (PIs), NH-Por-6FDA and Zn-Por-6FDA, with 5,15-bis­(4,-aminophenyl)-10,20-diphenylporphyrin (trans-DATPP) (electron donor) and 4,4′-(hexafluoroisoprpoylidine)­diphthalic anhydride (6FDA) (electron acceptor) as the building blocks for polymer memory applications. The chemical structures of the two polymers are mostly identical with the only difference lying in the zinc ion (Zn2+) insertion into the porphyrin core in the Zn-Por-6FDA. Electrical characterization indicates that the NH-Por-6FDA possesses bidirectional nonvolatile write once read many times (WORM) memory behavior, while the Zn-Por-6FDA shows vastly different volatile static random access memory (SRAM) behavior. Both polymer memory devices show high ON/OFF current ratio up to 106 and exhibit excellent long-term operation stability in 108 read cycles and retention time of 4000 s with no current degradation. The charge transfer (CT) and function of the donor/acceptor moiety in the polymers related with the electrical switching effect are elucidated on the basis of optical, electrochemical measurement, and quantum simulation results. The inserted zinc ion in the porphyrin is suggested to form an internal electrode and act as a bridge during the electronic transition process, which facilitates both the CT and back CT, consequently triggering the WORM/SRAM conversion upon Zn complexation. The results observed here indicate the significance of metal-complexation on the memory effects, and will attract the attention of the researchers to use noble transition metals for the suitable expecting memory devices.

In this work, three functional polyimides, in which the diaminophenylaminoanthracene (DAPAA) group served as the electron donor and 4,4′-hexafluoroisopropylidene dianhydride (6FDA) served as the electron acceptor, were synthesized and denoted as 1-DAPAA-6FDA, 2-DAPAA-6FDA, and 9-DAPAA-6FDA. The only difference between the three polyimides was that the anthracene group in DAPAA was attached to the nitrogen atom through different tethering positions (1-, 2-, and 9-). Characterization results indicate that the 1-DAPAA-6FDA and 9-DAPAA-6FDA based memory devices exhibit nonvolatile write once read many times memory (WORM) behavior, while the 2-DAPAA-6FDA based memory device exhibits volatile static random access memory (SRAM) behavior. Quantum chemical calculation results indicate that a lower dihedral angle between the anthracene group and the molecular backbone of 2-DAPAA-6FDA caused better coplanar structure for charge transfer (CT) and back CT processes, which accounts for the observed volatile SRAM memory performance. All of the polyimides possess excellent long-term operational stability. This work reveals the possibility of tuning memory behavior by elaborately adjusting the spatial conformation of the electron donor, providing feasible guidance for the design of polymer memory materials.

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