Publications by authors named "Chungryong Choi"

Surface fogging is a common phenomenon that can result in restricted visibility, reduced light absorption, and image distortion. Although both hydrophobic and hydrophilic surfaces are effective in preventing this phenomenon, typical coatings in both have limitations, including low durability and the need for frequent reapplication. To address these issues, a highly durable anti-fogging film that lasts over five weeks, even under high moisture conditions, while maintaining a promising degree of transparency (> 60%) is developed.

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Pressure-sensitive adhesives (PSAs) based on poly(acrylate) chemistry are common in a wide variety of applications, but the absence of backbone degradability causes issues with recycling and sustainability. Here, we report a strategy to create degradable poly(acrylate) PSAs using simple, scalable, and functional 1,2-dithiolanes as drop-in replacements for traditional acrylate comonomers. Our key building block is α-lipoic acid, a natural, biocompatible, and commercially available antioxidant found in various consumer supplements.

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Non-noble transition metal hydroxides have been widely used in electrochemical devices because of low cost and multiple redox states. In particular, self-supported porous transition metal hydroxides are used to improve the electrical conductivity, as well as achieving fast electron and mass transfer and a large effective surface area. Herein, we introduce facile synthesis of self-supported porous transition metal hydroxides using a poly(4-vinyl pyridine) (P4VP) film.

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Triboelectric nanogenerators (TENGs) have received significant attention for next-generation wearable electronics due to their simple device structure and low cost. Although the performance of TENGs is intimately tied to compressibility effects in the charge-generating layer, achieving high compressibility with conventional elastomers is challenging because molecular entanglements place a lower bound on the softness of cross-linked networks. Here, we demonstrate that bottlebrush elastomers are efficient charge-generating layers that improve the output performance of TENGs, including voltage, current, and surface potential, by minimizing entanglements and decreasing the compressive modulus ().

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Graphene is a promising active material for electric double layer supercapacitors (EDLCs) due to its high electric conductivity and lightweight nature. However, for practical uses as a power source of electronic devices, a porous structure is advantageous to maximize specific energy density. Here, we propose a facile fabrication approach of mesoporous graphene (-G), in which self-assembled mesoporous structures of poly(styrene)--poly(2-vinylpyridine) copolymer (PS--P2VP) are exploited as both mesostructured catalytic template and a carbon source.

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Among many possible nanostructures in block copolymer self-assembly, helical nanostructures are particularly important because of potential applications for heterogeneous catalysts and plasmonic materials. In this work, we investigated, via small-angle X-ray scattering and transmission electron microscopy, the morphology of a polystyrene--polyisoprene--polystyrene--poly(2-vinylpyridine) (SISV) tetrablock terpolymer. Very interestingly, when the volume fraction of each block was 0.

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Article Synopsis
  • Scientists have been working for a long time to create special materials called broadband absorbers that can soak up light really well for different uses.
  • Making these materials big enough and able to handle heat has been tough because it's expensive and complicated to create them.
  • Now, researchers have made a strong and large titanium nitride absorber that works really well in visible light and even after getting super hot, which could help with things like solar energy and stealth technology.
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The authors perform directed self-assembly based on graphoepitaxy of symmetric six-arm star-shaped poly(methyl methacrylate)-block-polystyrene copolymer [(PMMA-b-PS) ] thin film. The affinity between each block and the trench wall is adjusted by using polymer brushes or selective gold (Au) deposition. When the surface of the trench is strongly selective for the PMMA block, (n+0.

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We introduce a novel grafting-through polymerization strategy to synthesize dynamic bottlebrush polymers and elastomers in one step using light to construct a disulfide-containing backbone. The key starting material-α-lipoic acid (LA)-is commercially available, inexpensive, and biocompatible. When installed on the chain end(s) of poly(dimethylsiloxane) (PDMS), the cyclic disulfide unit derived from LA polymerizes under ultraviolet (UV) light in ambient conditions.

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We fabricated 3D nanoporous metal structures from poly(2-vinylpyridine)--poly(4-vinylpyridine) copolymer (P24VP) thin film with vertically oriented lamellar nanodomains by coordinating corresponding metal precursors followed by reduction to metals. Although metal precursors are coordinated with both P2VP and P4VP blocks, the metal coordination power toward P4VP block is much greater than that toward P2VP block. Thus, most of the metal precursors are located in the P4VP block, while a few exist in the P2VP block.

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Block copolymers (BCPs) with various nanostructures such as spheres, cylinders, gyroid, and lamellae, have received great attention for their application in nanolithography through nanopattern transfer to substrates. However, the fabrication of diverse geometries, shapes and sizes of nanostructure on a single substrate at the desired position could not be achieved because the nanostructure based on BCPs is mainly determined by the volume fraction of one block. Here, we synthesize polystyrene--poly(methyl methacrylate) copolymer (PS--PMMA), which contains a photocleavable linker at the junction point between PS and PMMA blocks.

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Block copolymers with various nanodomains, such as spheres, cylinders, and lamellae, have received attention for their applicability to nanolithography. However, those microdomains are determined by the volume fraction of one block. Meanwhile, nanopatterns with multiple shapes are required for the next-generation nanolithography.

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High density arrays of ferroelectric polymer nanodiodes have gained strong attention for next-generation transparent and flexible nonvolatile resistive memory. Here, we introduce a facile and innovative method to fabricate ferroelectric polymer nanodiode array on an ITO-coated poly(ethylene terephthalate) (PET) substrate by using block copolymer self-assembly and oxygen plasma etching. First, polystyrene-block-poly(2-vinylpyridine) copolymer (PS-b-P2VP) micelles were spin-coated on poly(vinylidene fluoride-ran-trifluoroethylene) copolymer (P(VDF-TrFE)) film/ITO-coated PET substrate.

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