- Battery-inspired, nonvolatile, and rewritable memory architecture: A radical polymer-based organic device
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A nonvolatile, bistable, and rewritable organic memory device based on radical polymers was prepared and tested. The excellent performance of a battery-inspired memory architecture with a configuration of p- and n-type charge-transporting radical polymers sandwiching a dielectric layer was characterized. The ON-OFF ratio was more than 4 orders of magnitude, and retention and endurance cycles of more than 104 and 103, respectively, were accomplished. Copyright
- Yonekuta, Yasunori,Susuki, Kentaro,Oyaizu, Kenichi,Honda, Kenji,Nishide, Hiroyuki
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- Strategies for the generation of molecularly imprinted polymeric nitroxide catalysts
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(Chemical Equation Presented) Two strategies for preparing catalytically active molecularly imprinted nitroxide-containing polymers are outlined. Both strategies rely upon the thermal rearrangement chemistry of tertiary amine N-oxides. To this end, several polymers were prepared and the polymeric nitroxides were revealed by oxidation with m-CPBA. All of the resulting polymeric catalysts proved to be competent mediators of the oxidation of alcohols.
- Anderson, Christopher D.,Shea, Kenneth J.,Rychnovsky, Scott D.
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- Tacticity influence on the electrochemical reactivity of group transfer polymerization-synthesized PTMA
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Spectroscopic, thermal, and electrochemical characterization results are presented for the redox active polymer poly(2,2,6,6-tetramethyl-1- piperinidyloxy-4-yl methacrylate) or PTMA, synthesized by group transfer polymerization (GTP), and its precursors 4-hydroxy-tetramethylpiperidine-N-oxyl (HO-TEMPO) and 4-methacryloyloxy-tetramethylpiperidine-N-oxyl (MO-TEMPO). DSC analysis of synthesized PTMA showed that the glass transition temperature (Tg) of the polymer structure occurs at 155 °C, corroborated by dynamic mechanical analysis (DMA), which is higher when compared with T g data for PTMA synthesized by other methods. Also, the amount of radical species present in PTMA synthesized by GTP reactions (100%) is higher than the values typically upon synthesizing PTMA by radical polymerization. Electrochemical and spectroelectrochemical-electron spin resonance studies in acetonitrile revealed two redox events in the PTMA polymer, one of which is reversible, accounting for ca. 80% of the spins in the polymer and giving rise to the battery behavior. The other redox event is irreversible, accounting for the remaining ca. 20% of spins, which has not previously been reported. These two redox events are linked to a structural property associated with the tacticity of the polymer, where the reversible feature (responsible for cathode behavior) is the dominant species. This corresponds to a number of isotactic domains of the polymer (determined by high temperature 1H NMR). The second feature accounts for the three-line impurity observed in the ESR, which has been reported previously but poorly explained, associated to the number of heterotactic/syndiotactic triads.
- Lopez-Penna, Hugo A.,Hernandez-Munnoz, Lindsay S.,Frontana-Uribe, Bernardo A.,Gonzalez, Felipe J.,Gonzalez, Ignacio,Frontana, Carlos,Cardoso, Judith
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- LIQUID-CRYSTALLINE MEDIUM AND LIQUID-CRYSTAL DISPLAY COMPRISING THE SAME
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The present invention relates to a liquid-crystalline medium (LC medium) comprising a polymerizable piperidine derivative as an additive for stabilization, to the use thereof for electro-optical purposes, and to LC displays containing this medium, particularly to liquid-crystal displays which use the IPS (in-planeswitching) or the FFS (fringefieldswitching) effect using dielectrically positive liquid crystals.
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Page/Page column 93
(2019/04/16)
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- Functional nitroxyls for use in delayed-onset polyolefin cross-linking
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A new approach to controlling the dynamics and yields of polyolefin radical cross-linking is described, wherein 4-acryloyloxy-2,2,6,6- tetramethylpiperidine-N-oxyl (AOTEMPO) is used to quench macroradicals in the early stages of the process and to subsequ
- Hyslop, David K.,Parent, J. Scott
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p. 8147 - 8154
(2013/01/15)
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