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Preparation of carbon dots decorated graphene/polyaniline composites by supramolecular in-situ self-assembly for high-performance supercapacitors
摘要： Supramolecular in-situ self-assembly is achieved to prepare carbon nanodots decorated graphene/polyaniline composites by adding β-cyclodextrin (β-CD) as the bonding agent in this work. With its unique structure, β-CD can form a supramolecular system with graphene oxide layers, generating the inclusion compound with aniline monomers, which makes the in-situ polymerization of polyaniline on the surface of graphene oxide. In the hydrothermal process, β-CD is carbonized to carbon nanodots anchored on the surface of reduced graphene oxide. The scanning electron microscopy (SEM) images show that the prepared reduced graphene oxide/carbon nanodots/polyaniline (RGO@CN/PANI) nanocomposites exhibit the micro morphology of a regular polyaniline particle array on the surface of graphene layers. The electrochemical tests demonstrate that the RGO@CN/PANI nanocomposites exhibit high specific capacitance (up to 871.8 F g-1 at 0.2A g-1), low charge transfer resistance (Rct), and presentable cycling performance (72% capacitance retention after 10000 cycles), indicating the satisfied performance for supercapacitors. The promising performance of RGO@CN/PANI can be attributed to the synergistic effect of RGO, carbon nanodots and PANI, as well as the regular microstructure in which the effective reaction area of polyaniline is increased and the rapid ion transport channel is provided.
关键词： β-cyclodextrin,supramolecular in situ self-assembly,Carbon dots modified Graphene,polyaniline
更新于2025-09-04 15:30:14
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Silver Metallic Cyclodextrin-Core Star mPEG
摘要： A novel silver metallic β-cyclodextrin (β-CD)-core star methoxypolyethylene glycol (mPEG) (SM-CD-SPEG) is presented. For this, a well-defined water-soluble β-CD-core star mPEG with aldehyde groups (CD-star(ald)PEG, III) is first designed and synthesized via the copper-catalyzed azide–alkyne click reaction. Then, silver nanoparticles are formed within III through the oxidation–reduction reaction between the aldehyde groups and silver ions. The oxidation–reduction reaction is characterized by means of 1H NMR spectra. And the preparation conditions of SM-CD-SPEG are optimized. The resulting SM-CD-SPEG aqueous solutions exhibit good stability and a unimolecular micelle morphology. Significantly, it is able to obtain solid SM-CD-SPEG samples with molecular water-solubility. This is convenient for storage and further application of SM-CD-SPEG. The SM-CD-SPEG samples also show good catalytic performance toward the reduction reaction of methylene blue (MB) by sodium borohydride (NaBH4).
关键词： metallic polymers,cyclodextrin,star polymers,unimolecular micelles
更新于2025-09-04 15:30:14
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Photophysics of Przewalskinone-B and its Binding Behavior with β- Cyclodextrin
摘要： The photophysical properties of Przewalskinone-B, a plant extract which is reported widely for its medicinal values were studied in the absence and presence of a drug carrier, β-Cyclodextrin. The steady state absorption, fluorescence excitation and emission spectra of Przewalskinone-B were studied in an aqueous medium. The fluorescence emission of Przewalskinone-B was analysed in presence of varying concentrations of β-Cyclodextrin in an alcohol/water medium. An appreciable quenching was observed in the emission intensity of Przewalskinone-B. There was also a red shift observed in both absorption and emission spectra in presence of β-Cyclodextrin which designated a convinced interaction between the two species.
关键词： Emission,Przewalskinone-B,Binding,β-Cyclodextrin
更新于2025-09-04 15:30:14
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A Spectroscopic Study of a Cyclodextrin-Based Polymer and the “Molecular Accordion” Effect
摘要： The formation of host-guest complexes was studied for two hosts; β-cyclodextrin (β-CD) and a cross-linked polymer containing an equimolar ratio of β-CD and hexamethylene diisocyanate (HDI), denoted as HDI-1. The thermodynamics of host-guest binding was studied with 1-anilinonaphthalene-8-sulfonic acid (1,8-ANS) using steady-state fluorescence spectroscopy in aqueous solution at variable temperature and ambient pH. The association of 1,8-ANS with β-CD and HDI-1, showed a fluorescence enhancement of ~4 and 12 units, respectively. Greater fluorescence enhancement for the polymer/dye system indicates the presence of multiple binding sites (inclusion vs. interstitial). By contrast, the β-CD/dye system adopt trends that indicate the formation of well-defined inclusion complexes. HDI-1 has inclusion sites (β-CD) and interstitial domains (HDI) that afford dual binding with variable binding affinity. Simplified binding models employed herein address the role of inclusion binding without an explicit account for higher order or secondary binding equilibria. The approximate 1:1 binding constant (K1:1) for CD/1,8-ANS is about two-fold greater over the HDI-1/1,8-ANS system. HDI-1 displays cooperative effects among the polymer subunits, according to changes in relative fluorescence intensity due to structural transitions and binding site loci. The relative fluorescence intensities of the HDI-1/1,8-ANS system relate to a reversible temperature-driven structural transition (globular ? extended) between 5 oC and 60 °C of the polymer, in contrast to the β-CD/1,8-ANS complex. The temperature- and guest-driven structural transition, described as the “molecular accordion” effect is supported by new insight provided by complementary fluorescence and 1H NMR spectral results in aqueous solution.
关键词： Complex formation,Host-Guest,Fluorescence,Responsive polymers,Cyclodextrin
更新于2025-09-04 15:30:14