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Creators/Authors contains: "Char, Kookheon"

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  1. null (Ed.)
  2. In this report, a new class of functional chalcogenide hybrid inorganic/organic polymers (CHIPs) bearing free aryl amine groups that are amenable to post-polymerization modifications were synthesized. These functional CHIPs were synthesized via the inverse vulcanization of elemental sulfur with 4-vinylaniline without the need for functional group protection of amines. This polymer is the first example of a polysulfide or CHIP material to carry a useful primary amine functional group which can be successfully post functionalized with acid chlorides and isocyanates to improve the mechanical properties. 
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  3. ABSTRACT

    Recent developments in the use of polymeric materials as device components in lithium sulfur (Li‐S) batteries are reviewed. Li‐S batteries have generated tremendous interest as a next generation battery exhibiting charge capacities and energy densities that greatly exceed Li‐ion battery technologies. In this Highlight, the first comprehensive review focusing on the use of polymeric materials throughout these devices is provided. The key role polymers play in Li‐S technology is presented and organized in terms of the basic components that comprise a Li‐S battery: the cathode, separator, electrolyte, and anode. After a straightforward introduction to the construction of a conventional Li‐S device and the mechanisms at work during cell operation, the use of polymers as binders, protective coatings, separators, electrolytes, and electroactive materials in Li‐S batteries will be reviewed. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem.2017,55, 1635–1668

     
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  4. Abstract

    Optical technologies in the long‐wave infrared (LWIR) spectrum (7–14 μm) offer important advantages for high‐resolution thermal imaging in near or complete darkness. The use of polymeric transmissive materials for IR imaging offers numerous cost and processing advantages but suffers from inferior optical properties in the LWIR spectrum. A major challenge in the design of LWIR‐transparent organic materials is that nearly all organic molecules absorb in this spectral window which lies within the so‐called IR‐fingerprint region. We report on a new molecular‐design approach to prepare high refractive index polymers with enhanced LWIR transparency. Computational methods were used to accelerate the design of novel molecules and polymers. Using this approach, we have prepared chalcogenide hybrid inorganic/organic polymers (CHIPs) with enhanced LWIR transparency and thermomechanical properties via inverse vulcanization of elemental sulfur with new organic co‐monomers.

     
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