Natural pigments from plant sources are often stabilized by several types of protection systems, including incorporation of co-pigment compounds, formation of supramolecular complexes, and ...encapsulation or loading using nano-carriers. Inspired by Maya blue, clay minerals as a kind of promising nano-carriers are employed to stabilize the natural pigments due to their unique structural characteristics, abundant reserves, cheap and eco-friendly nature. The unique features in the structures and physicochemical properties of clay minerals provide the opportunity to stabilize these natural pigments. This review summarizes the most recent studies and provides the insight into the natural or synthetic clay minerals for enhancing the environmental stability of natural pigments extracted from various fruits, vegetables and flowers. Based on the cognition and accumulation combining reviewing the literatures with our relevant research achievements, several suggestions are proposed for the design and the potential applications of hybrid materials composed of clay mineral and natural pigments.
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•Innate disadvantages of natural pigments severely limited their wide applications.•Clay minerals are promising carriers for enhancing the stability of plant pigments.•Recent advances on natural plant pigments stabilized by clay minerals are reviewed.•Several suggestions are proposed for clay mineral-based organic/inorganic hybrid materials.
UiO-66 is an archetypal metal–organic framework (MOF) with a very high surface area as well as high thermal stability. It is found that the stability can be attributed to the metal oxide node being ...cuboctahedral allowing for 12 extension points for 1,4-benzenedicarboxylic acid (BDC) coordination. Because of this and its exceptional tunability and functionality, which are largely due to defect control of both missing-cluster and missing-linker defects, UiO-66 has gained scientific popularity. The combination of these characteristics allows for a highly versatile material that can be adapted to many different applications. The purpose for this work is to provide a historic overview of UiO-66, outlining the major developments that changed the synthesis strategies of Zr-based MOF as well as current and future works, which include defect control, aqueous crystallization, functionality-stability trade-offs, and advanced topographies. A breakdown of the various UiO-66 structures, including isoreticular and reo-type, and different characterization techniques such as powder X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, and nitrogen porosimetry are discussed as well.
•Attapulgite/bentonite composites were prepared as adsorbent for MB removal.•Compared to bentonite, salt resistance and adsorption rate of composite increased.•Compared to attapulgite, adsorption ...capacity of composite greatly increased.•MB loaded adsorbents were not easily desorbed by diluted HCl and NaOH solution.
Attapulgite/bentonite composite adsorbents have been prepared via high-pressure homogenization technique. It was aimed to investigate the synergistic effect of one-dimensional attapulgite and two-dimensional bentonite on the adsorption property for methylene blue (MB) from aqueous solution in this paper. The process parameters affecting adsorption behaviors such as bentonite content, pH of MB solution, contact time and initial concentration were systematically investigated. The results showed that the adsorption capacity of the adsorbents increased with the increase in the content of bentonite while the adsorption rate decreased due to the decrease in the content of attapulgite. The adsorption process could be well described by pseudo-second-order kinetics and Langmuir isotherm model rather than Freundlich and Temkin isotherm models. The MB loaded adsorbents were not easily desorbed with diluted HCl or NaOH solution, and thus can be employed as candidates for organic–inorganic pigments.
By combining the virtues of conventional linear and hyperbranched polymers, long‐chain hyperbranched polymers (LCHBPs) have attracted great attention. Therefore, a comprehensive summary of the ...research progress of LCHBPs is presented, with a particular focus on their synthetic strategies, unique properties, and potential applications. The synthetic methodologies are rationalized into four main classes according to their construction process or mechanism, namely ABx (x ≥ 2), A2 + Bx (x ≥ 3), AB + ABx (x ≥ 2), and self‐condensing vinyl polymerization. Some of their rheological properties, self‐assembly behavior, and stimuli‐response features are then discussed. Finally, the emergent applications including biomedicine, electrical conductivity, chemical sensing, and catalyst carrier, are outlined. It is anticipated that this review will stimulate more inspiration for advancing the development of this novel kind of LCHBP.
Long‐chain hyperbranched polymers combine the advantages of conventional hyperbranched polymers and linear polymers, and thus may present certain superiority in structures and performance beyond both of them. Research progress on the synthetic methods, unique properties, and emergent applications of long‐chain hyperbranched polymers is comprehensively reviewed, and some problems and challenges in this novel kind of polymer are also discussed.
The graphene-MnO
2
-polyaniline (rGO-MnO
2
-PAn) ternary composites were prepared
via in situ
chemical oxidative polymerization of polyaniline on the MnO
2
decorated graphene sheets. The graphene ...sheets were treated with KMnO
4
in a water-ethylene glycol system using the hydrothermal method to complete the loading of MnO
2
on the graphene sheets, while the graphene oxide (GO) sheets were hydrothermally reduced to reduced graphene oxide (rGO). The glycol was introduced as a reductant to react with MnO
4
−
, and GO was protected from consumption in the process of deposition of MnO
2
. The structures and morphologies of the resulting ternary composites are characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffractometry (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The electrochemical properties of the composites as potential electrode materials for supercapacitors were investigated using different electrochemical techniques including cyclic voltammetry (CV), galvanostatic charge-discharge, and electrochemical impedance spectroscopy (EIS). The specific capacitance of a rGO-MnO
2
-PAn composite electrode was 395 F g
−1
at 10 mA cm
−2
in 1 M H
2
SO
4
solution. The composites displayed good cycle stability retaining 92% of their original specific capacitance after 1200 cycles by continuous cyclic voltammetric scans at 100 mV s
−1
.
The graphene-MnO
2
-polyaniline (rGO-MnO
2
-PAn) ternary composites were prepared
via in situ
chemical oxidative polymerization of polyaniline on the MnO
2
decorated graphene sheets.
Using graphene as adsorbent for removal of pollutants from polluted water is commonly recognized to be costly because the graphene is usually produced by a very complex process. Herein, a simple and ...eco-friendly method was employed to fabricate efficient superparamagnetic graphene/polyaniline/Fe3O4 nanocomposites for removal of dyes. The exfoliation of graphite as nanosheets and the functionalization of nanosheets with polyaniline and Fe3O4 nanoparticles were simultaneously achieved via a one-pot reaction process combining the intercalation polymerization of aniline and the co-precipitation of the residual Fe3+ and the generated Fe2+. The obtained graphene/polyaniline/Fe3O4 nanocomposites exhibited excellent adsorption performance for Congo red, even in the presence of Brilliant green. The adsorption kinetics and adsorption isotherms were well fitted with pseudo second-order kinetic model and Langmuir isotherm model, respectively. In a word, this method is simple and industrially feasible, which provides a new approach to fabricate highly efficient graphene-based adsorbents on large scale for removal of dyes. In addition, it also can be used to exfoliate other two-dimensional materials, such as boron nitride, carbon nitride and MoS2 for a range of possible applications.
Developing discotic columnar liquid crystals (LCs) with both high electrical conductivity and strong luminescence remains a challenge because the intracolumnar interdisc π–π stacking usually in ...ordered discotic columnar LCs is essential to generate charge transport pathways but normally detrimental to light emissions. We here present tricyanotristyrylbenzene-based quasi-discotic LCs upon bearing three wedge-shaped alkyl tails for addressing this issue. The resulted columnar materials displayed both high electrical conductivity and strong luminescence, especially for the ones stabilized by multivalent hydrogen-bonding interactions. Besides, an interesting thermochromic luminescence tuning behavior in a smooth manner was observed over a wide wavelength range for the hydrogen bond-stabilized columnar LCs. This study will lead to the future design and application of new multifunctional optoelectronic materials by integrating excellent conductivity and luminescence tuning behaviors.
Thermal stability and heat capacity of several metal–organic frameworks and their corresponding organic ligands have been investigated systematically using TGA-DSC technique. A simple notation system ...was created to present the local coordination environment around metal atoms in a secondary building unit (SBU). The heat capacity contributions of organic functional groups and SBUs were examined using the group-contribution method. Our results suggest that the thermal stability of MOFs is determined by the coordination number and local coordination environment instead of framework topology. Specific heat capacities (Cp ) of all examined MOFs exhibit comparable values as other solids including carbon nanotubes, zeolites, and minerals. The molar heat capacity contributions of SBUs in MOFs indicate similar abnormal thermal behavior as negative thermal expansion of MOFs.
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•Well-defined microtubular CKF/NiO composite has been prepared.•The as-prepared composites exhibit the maximum capacitance of 575.5Fg−1.•An ASC device of CKF/NiO-400-2//AC shows high ...energy density of 7.5Whkg−1.•This scalable protocol can be used to fabricate other microtubular composites.
Design and fabrication of structurally optimized electrode materials using biomass materials has become one of the hottest subjects in the field of electrochemical energy storage. Hollow tubular carbonized kapok fiber/NiO composites are synthesized by a facile hydrothermal and carbonization procedure using kapok fiber as a low-cost template. Owing to their unique microtubular structure, the as-prepared composites exhibit a high specific capacitance of 575.7Fg−1 at current density of 0.5Ag−1. Furthermore, an asymmetric supercapacitor device also has been fabricated using carbonized kapok fiber/NiO composites and commercial activated carbon as the positive and negative electrodes, respectively. Because of its unique structure, high capacitive performance, and complementary potential window, the asymmetric supercapacitor device can be cycled reversibly at a cell voltage of 1.6V in 1.0M KOH aqueous electrolyte, delivering a high energy density of 7.5Whkg−1 at a power density of 64.6Wkg−1. In addition, the asymmetric supercapacitor device also exhibits a superior long cycle life and the capacitance retention of the initial specific capacitance cannot found clearly degeneration after 4000 cycles. It is worth noting that this scalable protocol also can be employed to prepare other microtubular carbon/metal oxide composites with good electrochemical performances.
As the shortest segment of carbon nanotubes (CNTs), cycloparaphenylenes (CPPs) offer a well‐defined alternative for CNTs as the fluorophores in bioimaging. However, most of CPPs emit blue or yellow ...light, the bright red‐emitting CPP materials required by bioimaging, particularly in vivo imaging, are still lacking. Here, it is shown that a CPP (TB9CPP) with red emission up to 650 nm is successfully synthesized and characterized. The fluorescence quantum yields of TB9CPP are measured up to 44% in chloroform and 17% as nanodots in aqueous media. Meanwhile, the water‐soluble nanodots present outstanding three‐photon fluorescence performances, thereby are utilized for in vivo probing of brain vessels by three‐photon fluorescence microscopic imaging technique, exhibiting a high penetration depth, good resolution, and clear image contrast.
A bright red emissive segment of carbon nanotube TB9CPP is realized by a combined strategy of ring‐shrinking and D‐A conjugation. The water‐soluble nanodots of TB9CPP with an emission at 650 nm are used for three‐photon fluorescence bioimaging of mouse cerebrovascular, showing high penetration depth, resolution, and image contrast.
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