Publications by authors named "Che-Yi Chu"

Article Synopsis
  • Designing efficient organic polymer photocatalysts for hydrogen production using visible and near-infrared (NIR) light remains challenging.
  • Researchers developed a new series of polymer nanoparticles (Pdots) using ITIC and BTIC units with different π-linkers, which work effectively alone without needing to combine with other materials.
  • The difluorothiophene (ThF) π-linker improves charge transfer between donor and acceptor components in the polymers, resulting in significantly enhanced hydrogen production rates of 279 µmol/h with visible light and 20.5 µmol/h with NIR light, and an apparent quantum yield of 4.76% at 700 nm.
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Montmorillonite (MMT) has been frequently utilized as drug vehicles due to its high specific surface area, excellent cation exchange capacity and biocompatibility. However, the significant flocculation of MMT under physiological condition restricted its application to drug delivery. To conquer this problem, the graft-type PEGylated chitosan (PEG-CS) adducts were synthesized as intercalator to stabilize MMT dispersion.

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Photocatalytic water splitting is attracting considerable interest because it enables the conversion of solar energy into hydrogen for use as a zero-emission fuel or chemical feedstock. Herein, we present a universal approach for inserting hydrophilic non-conjugated segments into the main-chain of conjugated polymers to produce a series of discontinuously conjugated polymer photocatalysts. Water can effectively be brought into the interior through these hydrophilic non-conjugated segments, resulting in effective water/polymer interfaces inside the bulk discontinuously conjugated polymers in both thin-film and solution.

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This investigation reports the nanostructural evolution and associated encapsulation and elution of a hydrophobic drug, demethoxycurcumin (DMC), as a molecular probe, with the carboxymethyl-hexanoyl chitosan (CHC), which has been a technically interesting amphiphilic chitosan-based polymer successfully developed in this lab for years. The self-assembly nature of the CHC in neutral aqueous solutions allowed efficient encapsulation of various drugs without deteriorating or changing drugs' activity. However, its self-assembly behavior associated with nanostructural stability or variation, in terms of residence time in aqueous solution has not been well characterized and how the CHC nanostructure may be altered upon entrapping a drug, followed releasing out of the nanostructure.

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Self-assembled hydrogen-bonded networks of the polysaccharide pectin, a mechanically functional component of plant cell walls, have been of recent interest as biomimetic exemplars of physical gels, and the microrheological and strain-stiffening behaviors have been previously investigated. Despite this detailed rheological characterization of preformed gels, little is known about the fundamental arrangement of the polymers into cross-linking junction zones, the size of these bonded regions, and the resultant network architecture in these hydrogen-bonded materials, especially in contrast to the plethora of such information available for their well-known calcium-assembled counterparts. In this work, in concert with pertinent rheological measurements, an in-depth structural study of the hydrogen-bond-mediated gelation of pectins is provided.

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Theoretical models predict that a variety of self-assembled structures of closely packed spherical particles may result when they are confined in a cylindrical domain. In the present work we demonstrate for the first time that the polymer-coated nanoparticles confined in the self-assembled cylindrical domains of a block copolymer pack in helical morphology, where we can isolate individual fibers filled with helically arranged nanoparticles. This finding provides unique possibilities for fundamental as well as application-oriented research in similar directions.

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Water-cast nanocomposite films formed by poly(ethylene oxide) (PEO) and Laponite clay were found to display three characteristic levels of structure with large-scale orientation. The first level with the length scale of ca. 30-50 nm was the clay lamellar bundles, which tended to stack perpendicularly to the film surface.

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Heparin is a potent anticoagulant; however, it is poorly absorbed in the gastrointestinal tract. In this study, we developed a nanoparticle (NP) system shelled with chitosan (CS) for oral delivery of heparin; the NPs were prepared by a simple ionic gelation method without chemically modifying heparin. The drug loading efficiency of NPs was nearly 100% because a significantly excess amount of CS was used for the CS/heparin complex preparation.

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