Organic-inorganic Hybrid Matrix Research Articles

Enzymatic dual-faced Janus structures based on the hierarchical organic-inorganic hybrid matrix for an effective bioremoval and detoxification of reactive blue-19

A novel, dual-faced, and hierarchical type of Janus hybrid structures (JHSs) was assembled through an in situ growing of lipase@cobalt phosphate sheets on the laccase@copper phosphate sponge-like structures. The chemical and structural information of prepared JHSs was investigated by Scanning electron microscopy-energy dispersive X-ray analysis (SEM-EDX), Fourier Transform Infrared Spectroscopy (FTIR), and X-ray diffraction analysis (XRD). The catalytic activity, storage stability, and reusability of JHSs were then investigated. The SEM-EDX analysis clearly confirmed the asymmetric morphology of the fabricated JHSs with two distinct metal distributions. Under optimized synthesis conditions, the prepared JHSs showed 97.8 % and 100 % of laccase and lipase activity, respectively. Compared to the free biocatalysts, the immobilization resulted in ~ a 2-fold increase in laccase and lipase stability at temperatures of >40 °C. The fabricated JHSs maintained 61 % and 90 % of their original laccase and lipase activity upon 12 successive repetition cycles. Up to 80 % of Reactive Blue-19 (RB-19), an anthraquinone-based vinyl sulphone dye, was removed after 5 h treatment with the prepared JHSs (50 % higher than the free forms of laccase and lipase). The dye removal data fitted very well on the pseudo-second-order kinetic model with a rate constant of 0.8 g mg−1 h−1. Following the bioremoval process, bacterial toxicity also decreased by about 70 %. Therefore, the prepared JHSs provide a facile and sustainable approach for the decolorization, biotransformation, and detoxification of RB-19 by integrating enzymatic oxidation and hydrolysis.

Self-Enhanced Antibacterial and Antifouling Behavior of Three-Dimensional Porous Cu2O Nanoparticles Functionalized by an Organic-Inorganic Hybrid Matrix.

Cu2O is currently an important protective material for domestic engineering and equipment used to exploit marine resources. Cu+ is considered to have more effective antibacterial and antifouling activities than Cu2+. However, disproportionation of Cu+ in the natural environment leads to its reduced bioavailability and weakened reactivity. Novel and functionalized Cu2O composites could enable efficient and environmentally friendly applications of Cu+. To this end, a series of three-dimensional porous Cu2O nanoparticles (3DNP-Cu2O) functionalized by organic (redox gel, R-Gel)-inorganic (reduced graphene oxide, rGO) hybrids─3DNP-Cu2O/rGOx@R-Gel─at room temperature by immobilization-reduction method was prepared and applied for protection against marine biofouling. 3DNP-Cu2O/rGO1.76@R-Gel includes rGO and R-Gel shape 3D porous Cu2O nanoparticles with diameters ∼177 nm and strong dispersion and antioxidant stability. Compared with commercial Cu2O (Cu2O-0), 3DNP-Cu2O/rGO1.76@R-Gel exhibited an ∼50% higher bactericidal rate, ∼96.22% higher water content, and ∼75% lower adhesion of mussels and barnacles. Moreover, 3DNP-Cu2O/rGOx@R-Gel maintains the same excellent, stable, and long-lasting bactericidal performance as Cu2O-0@R-Gel while reducing the average copper ion release concentration by ∼56 to 76%. This was also confirmed by X-ray diffraction, X-ray photoelectric spectroscopy (XPS), atomic absorption spectroscopy, and antifouling tests. In addition, XPS tests of rGO-Cu2+ and R-Gel-Cu2+, photocurrent tests of 3DNP-Cu2O/rGO1.76@R-Gel, and energy-dispersive spectrometry pictures of bacteria confirm that R-Gel and rGO act as electron donors and transfer substrates driving the reduction of Cu2+ (Cu2+ → Cu+) and the diffusion of Cu+. Thus, a self-growing antibacterial and antifouling system of 3DNP-Cu2O/rGO1.76@R-Gel was achieved. The mechanism of accelerated bacterial inactivation and resistance to mussel and barnacle adhesion by 3DNP-Cu2O/rGO1.76@R-Gel was interpreted. It is shown that rGO and R-Gel are important players in the antibacterial and antifouling system of 3DNP-Cu2O/rGO1.76@R-Gel.

Green host urethanesil based on castor oil doped with Eu3+ complex

Polymers based on vegetable oils can be suitable candidates for the replacement of fossil polymers, for instance, polyurethanes (PU) based on castor oil. However, the synthesis PU materials are normally carried out using organic solvents, metals, and high temperatures. To overcome these problems, the sol-gel route is an alternative approach based on mild conditions to produce organic-inorganic hybrid urethanesil (Ut) environmentally friendly. Therefore, in this study, we proposed an organic-inorganic hybrid (OIH) synthesis based on castor oil (CO)-derived Ut, as well as the incorporation and interaction of europium β-diketone [Eu(tta)3(H2O)2] in organic-inorganic hybrid matrix. The Ut self-supporting hybrid was synthesized from the reaction of 3-(triethoxysilyl)propyl isocyanate (ICPTES) and CO in a 3:1 M ratio. The films were obtained using the sol-gel process, following the casting method. The CO-based OIH-Ut films showed high transmittance in the visible and infrared spectrum (90%), and urethanesil showed photoluminescence (PL) with emission at 416.0 nm when excited at 319.0 nm. The results also revealed an increase in the intrinsic quantum yield of PL (QLEu) for [Eu(tta)3(H2O)2]. It has been verified a QLEu value of 27% for the isolated complex, whereas when it is incorporated into OIH-Ut a value of 49% was observed.

Photocatalytic Investigation of Aerosol-Assisted Atmospheric Pressure Plasma Deposited Hybrid TiO2 Containing Nanocomposite Coatings.

We report on the aerosol-assisted atmospheric-pressure plasma deposition onto a stainless-steel woven mesh of a thin nanocomposite coating based on TiO2 nanoparticles hosted in a hybrid organic−inorganic matrix, starting from nanoparticles dispersed in a mixture of hexamethyldisiloxane and isopropyl alcohol. The stainless-steel mesh was selected as an effective support for the possible future technological application of the coating for photocatalytically assisted water depollution. The prepared coatings were thoroughly investigated from the chemical and morphological points of view and were demonstrated to be photocatalytically active in the degradation of an organic molecule, used as a pollutant model, in water upon UV light irradiation. In order to optimize the photocatalytic performance, different approaches were investigated for the coating’s realization, namely (i) the control of the deposition time and (ii) the application of a postdeposition O2 plasma treatment on the pristine coatings. Both strategies were found to be able to increase the photocatalytic activity, and, remarkably, their combination resulted in a further enhancement of the photoactivity. Indeed, the proposed combined approach allowed a three-fold increase in the kinetic constant of the degradation reaction of the model dye methylene blue with respect to the pristine coating. Interestingly, the chemical and morphological characterizations of all the prepared coatings were able to account for the enhancement of the photocatalytic performance. Indeed, the presence of the TiO2 nanoparticles on the outmost surface of the film confirmed the accessibility of the photocatalytic sites in the nanocomposite and reasonably explained the enhanced photocatalytic performance. In addition, the sustained photoactivity (>5 cycles of use) of the nanocomposites was demonstrated.

Hybrid Ionogel Electrolytes for Advanced Lithium Secondary Batteries: Developments and Challenges.

Incidents in the use of lithium-ion batteries are usually caused by the malfunction of flammable organic liquid electrolytes with poor thermal stability. Therefore, the development of noncombustible electrolytes is regarded as one of the most effective means to prevent the safety hazards of lithium-ion batteries. Ionic liquids have attracted much interest recently, mainly due to their high ionic conductivity, low volatility, and incombustibility. The application of ionic liquids to the preparation of quasi-solid-state gel electrolytes combines the advantages of ionic liquids and avoids the risks of organic liquid electrolytes. Therefore, the solid-state ionogels have been considered as a promising alternative electrolyte system, especially for the much-desired energy storage devices with higher energy density and flexibility. This review focuses on the recent progress of ionogel electrolytes for lithium-ion batteries. The preparation strategies for ionogel electrolytes based on different frameworks, namely inorganic matrix, organic matrix, and organic-inorganic hybrid matrix, are discussed. Subsequently, efforts to improve the properties of the ionogel electrolytes, including the ionic conductivity, mechanical properties, and lithium-ion transfer number, are summarized. Besides, the applications of ionogel electrolytes in high-voltage lithium-ion batteries and lithium metal batteries as well as the batteries under extreme environments are outlined. Finally, the perspectives on studying and improving the performances of ionogel electrolytes for advanced lithium-ion batteries are provided.

Enhancement of the luminescent thermal stability and water resistance of K2TiF6:Mn4+ by organic inorganic hybrid matrix and surface passivation

Due to their attractive luminescent properties, Mn4+-activated fluoride red-emitting phosphors are significant for improving correlated color temperature (CCT) and color rendering index (Ra) of white light-emitting diodes (WLEDs). However, the inherent poor moisture resistance of these phosphors limits their further application in WLEDs. Herein, KTF:TEAH+,Mn4+-P (KTF:TEAH+,Mn4+ = K2TiF6:0.10(C2H5)3NH+,0.04Mn4+, P = passivation with citric acid solution) red emitting phosphor with good water resistance, high luminous intensity and good luminescent thermal stability was generated by combining ion exchange and surface passivation method. The experimental results show that: (a) Emission intensities of samples are improved by using an organic-inorganic hybrid matrix and surface passivation; (b) Water resistances of samples are greatly increased by surface passivation; (c) Negative thermal quenching (NTQ) effect of the samples are enhanced by using an organic-inorganic hybrid matrix and surface passivation. The reason for improvement of water resistance is assigned to the formation of a Mn4+ -rare protective layer on the surface of the sample after surface passivation. Furthermore, the mechanism of the strong NTQ effect is attributed to the increase of electron traps by using an organic-inorganic hybrid matrix and surface passivation. A WLED prototype capable of emitting warm white light (luminous efficiency = 108.6 lm/W, CCT = 3725 K, Ra = 88.4) was assembled by coating a mixture of KTF:TEAH+,Mn4+-P, epoxy resin and YAG:Ce3+ on a blue InGaN chip. These excellent properties indicate that the KTF:TEAH+,Mn4+-P has important application value in blue-excited WLEDs.

Photoelectrochemical reduction of nitrate to ammonia over CuPc/CeO2 heterostructure: Understanding the synergistic effect between oxygen vacancies and Ce sites

• CuPc/CeO 2 with rich OVs has been successfully fabricated for PEC NO 3 – reduction. • CuPc/CeO 2 exhibited the NH 3 production rate up to 1.16 μmol h -1 m −2 . • Thermodynamic and kinetic factors of PEC NRR have been synergistically optimized. • The isotope NMR result further confirmed the accuracy of NO 3 – → NH 3 conversion. Photoelectrochemical nitrate (NO 3 – ) reduction reaction (PEC NRR) is a promising technology to solve both environmental pollution and traditional energy crisis. However, the fabrication of efficient catalyst with controllable active sites for high selectivity is still challenging. In this work, copper phthalocyanine (C 32 H 16 CuN 8 )/cerium dioxide (CuPc/CeO 2 ) heterostructure has been designed as a model to understand the role of Ce 3+ /Ce 4+ pairs on the formation of oxygen vacancies (OVs), which helps for identifying the key factors to adjust the chemical adsorption and activation of NO 3 – in PEC NRR system. Furthermore, the unique organic–inorganic hybrid matrix significantly strengthens the relationship of solar harvest–carriers’ separation–NO 3 – reduction. CuPc/CeO 2 heterostructure exhibits a high NH 3 yield of 1.16 μmol h −1 cm −2 and Faradic efficiency of 33% (-0.6 V vs.), and the desirable PEC NRR could be well retained for 5 cycles. Therefore, the construction of CuPc/CeO 2 successfully optimizes the thermodynamic and kinetic factors in PEC NRR system, providing a new insight for organic–inorganic hybridization and NH 3 green production.

Submicron 3,4-dihydroxybenzoic acid-TiO2 composite particles for enhanced MALDI MS imaging of secondary metabolites in the root of differently aged baical skullcap.

Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI) has become an attractive technique for the localization and visualization of small molecules in various biological tissue sections. In this work, submicron 3,4-dihydroxybenzoic acid-TiO2 composite particles (3,4-DHB-TiO2 CPs) were synthesized for enhanced MALDI MSI of secondary metabolites in the root of Scutellaria baicalensis Georgi (baical skullcap). Submicron TiO2 particles were synthesized as starting materials by using a facile sol-gel method and chemically modified with six analogs of dihydroxybenzoic acids (DHB) (2,3-DHB, 2,4-DHB, 2,5-DHB, 2,6-DHB, 3,4-DHB, and 3,5-DHB). Among them, 3,4-DHB-TiO2 CPs provided superior performance in MALDI MSI of small molecules. Compared with conventional matrices, such as 2,5-dihydroxybenzoic acid (2,5-DHB) and α-cyano-4-hydroxycinnamic acid (CHCA), 3,4-DHB-TiO2 CPs exhibited low background noise and high detection sensitivity for the visualization of spatial distribution patterns of secondary metabolites in the roots of differently aged S. baicalensis by using MALDI MSI. The age-related spatial and content changes of flavonoids in S. baicalensis roots were demonstrated and further validated by liquid chromatography-mass spectrometry (LC-MS). This work provides a potential organic-inorganic hybrid matrix for MALDI MSI of secondary metabolites in plant tissues.

Supersaturable organic-inorganic hybrid matrix based on well-ordered mesoporous silica to improve the bioavailability of water insoluble drugs

Mesoporous silica with uniform 2-D hexagonal pores has been newly employed as facile reservoir to impove the dissolution rate of water insoluble drugs. However, rapid drug release from mesoporous silica is usually accompanied by the generation of supersaturated solution, which leads to the drug precipitation and compromised absorption. To address this issue, a supersaturated ternary hybrid system was constructed in this study by utilizing inorganic mesoporous silica and organic precipitation inhibitor. Vinylprrolidone-vinylacetate copolymer (PVP VA64) with similar solubility parameter to model drug fenofibrate (FNB) was expected to well inhibit the precipitation. Mesoporous silica Santa Barbara amorphous-15 (SBA-15) was synthesized in acidic media and hybrid matrix was produced by hot melt extrusion technique. The results of in vitro supersaturation dissolution test obviously revealed that the presence of PVP VA64 could effectively sustain a higher apparent concentration. PVP VA64 was suggested to simultaneously reduce the rate of nucleation and crystal growth and subsequently maintain a metastable supersaturated state. The absorption of FNB delivered by the organic-inorganic hybrid matrix was remarkably enhanced in beagle dogs, and its AUC value was 1.92-fold higher than that of FNB loaded mesoporous silica without PVP VA 64. In conclusion, the supersaturated organic-inorganic hybrid matrix can serve as a modular strategy to enhance the oral availability of water insoluble drugs.

Hydrophobic, organic–inorganic hybrid sol–gel coatings containing boehmite nanoparticles for metal corrosion protection

In this study, fluoro-functionalized hydrophobic/oleophobic hybrid nanocomposite coatings, which are highly resistant and transparent, long-lasting and mechanically stable, have been deposited on metal substrate surfaces by the sol–gel method. Organic–inorganic hybrid matrix was prepared using tetraethoxysilane and organically modified silicon alkoxide, namely 3-(glycidyloxypropyl) trimethoxysilane. Additionally, to increase hydrophobic behavior, a fluorinated silica-alkoxide precursor and AlO(OH) NPs were added to the hybrid matrix. Water and n-hexadecane contact angle, surface morphologies, thicknesses and surface roughness of the films were determined. Additionally, optical characterizations and mechanical properties of the films such as light transmittance, haze, clarity, gloss were investigated. A salt spray corrosion test and electrochemical corrosion measurements were also performed. Optimum properties were acquired in the hydrophobic hybrid nanocomposite coating containing 15 wt% of 3 nm AlO(OH) NPs.

Photopolymerized hybrids containing TiO2 nanoparticles for gradient-index lens

An ultra violet (UV)-cured nanocomposite material, based on TiO2 nanoparticles was prepared by sol-gel process from 3-(methacryloxy)propyltrimethoxysilane (MPTS) and 1,12-dodecanediol dimethacrylate (DDDMA). The evolution of structural properties for the inorganic-organic hybrid network was studied by FT-IR and NMR during UV curing, while the photo-polymerization kinetics of hybrid organic-inorganic matrix was evaluated using Raman spectroscopy. It was found that the three-dimensional (3D) organic-inorganic network was formed mainly by polymerization of C=C bonds in methacrylate units and Si–O–Ti bonds were formed when the hybrid matrix solution was cured by UV light. The influence of TiO2 dosage on the particle size and morphology was investigated by DLS and TEM respectively. We observed that introducing TiO2 nanoparticles into the polymeric matrix allows to fabricate a bulk nanocomposite with good optical quality and with positively charged particles that enables us to tailor the refractive index of the material; a property that can be potentially used in the production of GRIN lenses.

Hybrid piezochromic coatings for impact detection on composite substrates for aeronautic

Structural Health Monitoring (SHM) is a major issue in the aeronautic field, especially for impact detection on composite materials which can be time consuming. Impact-sensitive coatings are an interesting way to save costs and time associated with these monitoring operations. This paper describes the successful preparation of a reversible piezochromic coating for impacts detection on composite substrates. It results from the incorporation of piezochromic pigments into a hybrid organic-inorganic matrix. It has been optimized by studying and quantifying their piezochromic behavior by UV-visible spectroscopy. It revealed that the piezochromic properties of the sensitive coating and the pigments alone are quite different and ruled by the hardness of the film. The obtained sensitivity and threshold pressure are determined to be 28% GPa−1 and 0.2 GPa respectively.

Graphene oxide-based nanomaterial as a coating with anti-corrosion properties

In this work, the synthesis of reduced graphene oxide (rGO) and its incorporation into a hybrid organic-inorganic matrix is reported. The hybrid matrix was obtained from Bisphenol A diglycidyl Ether (DGEBA) and tetraethylorthosilicate (TEOS) as the organic and inorganic phase, respectively, up to have an optimal hybrid matrix (HYBRID) having both good adherence on steel surface and good microhardness. In addition, the rGO was added to HYBRID (HGO). DGEBA, HYBRID and HGO were used as coatings on the surface of different 1018 carbon steel coupons. The coupons were immersed in a H2SO4 solution, then electrochemistry impedance spectroscopy (EIS) measurements were carried out. The corrosion current density, the corrosion rates, and the inhibition efficiency were estimated. The results show that the addition of rGO to HYBRID contributes to obtain a coating with good corrosion protective properties.

Ureasil Organic-Inorganic Hybrid as a Potential Carrier for Combined Delivery of Anti-Inflammatory and Anticancer Drugs.

There continues to be a need to develop controlled-release systems loaded with multiple drugs with distinct pharmacological activities, such as anti-inflammatory and anticancer effects, which are able to provide the desired release of each drug, as a function of time. To this end, an elegant strategy was developed for the incorporation, in a one-step process, of the anti-inflammatory drug naproxen (NAP) and the anticancer drug 5-fluorouracil (5FU) into a ureasil organic-inorganic hybrid matrix. A ureasil-poly(oxyalkylene) (UPEO) matrix was prepared using a sol-gel route to obtain a versatile dual-drug delivery system. Small-angle X-ray scattering (SAXS) measurements and Fourier transform infrared spectroscopy (FTIR) demonstrated that the UPEO network is preserved upon loading with the two drugs NAP and 5FU. There was excellent agreement between the macroscopic swelling behavior (water uptake) and surface wettability (determined using contact angle measurements), with this behavior being closely correlated with the release profiles and playing an important role in the sustained delivery of both drugs from the hybrid matrix. The amounts of both drugs released simultaneously could be finely controlled by adjusting the pH of the aqueous medium, with the release presenting stimulus-responsive behavior. In an aqueous PBS medium, the dual-UPEO-release system presented excellent potential as a vehicle for the release of the water-soluble 5FU and water-insoluble NAP drugs, at identical rates, using a single carrier. This novel and adjustable dual-drug delivery UPEO system is a promising hybrid material carrier with the ability to simultaneously incorporate a wide range of therapeutic agents for the treatment of various diseases, including cancers.

Robust and flexible thermal-plasticizing 3D shaped composite films with invariable and brilliant structural color

We present a novel flexible thermal-plasticizing 3D shaped composite film with invariable structural color through an organic–inorganic hybrid matrix design.

Functionalized superhydrophobic coatings with micro-/nanostructured ZnO particles in a sol–gel matrix

Among the methods to create superhydrophobic surfaces by wet chemistry, one of the strategies consists in coating the substrate with a hydrophobic polymer with specific morphology. Such elaborated surfaces are largely developed and can present complex architectures but are generally fragile. Ceramic-based coatings show better durability. In this work, a new route associating inorganic and polymeric parts is used. Surfaces with superhydrophobic properties are prepared with a mixture of zinc oxide (ZnO) particles in a hybrid organic inorganic matrix prepared via sol–gel route. ZnO particles were synthesized by the inorganic polycondensation route and exhibit an appropriate micro-/nanostructure for superhydrophobicity. Sol–gel matrix is obtained by the alkoxide route with aluminum-tri-sec-butoxide (ASB) and (3-glycidoxypropyl)trimethoxysilane (GPTMS). A step of octadecylphosphonic acid (ODP) functionalization on ZnO particles and on film surfaces was employed to considerably improve hydrophobic properties. This new route enables to obtain superhydrophobic coatings that exhibit water contact angles superior to 150°. These coatings show a homogeneous and smooth coverage on aluminum alloy substrate. Results attest the significance of the synergy for superhydrophobic coatings: a micro-/nanostructured surface and an intrinsic hydrophobic property of the material. The durability of the coatings has also been demonstrated with only a slight decrease in hydrophobicity after erosion.

Organic-inorganic hybrid matrix for electrochemical biosensing of tyrosine

The manuscript presents synthesis and application of organic-inorganic hybrid matrix, consisting of polypyrrole (PPy) and gold nanoparticles (AuNPs). The polypyrrole acts as conducting matrix and gold nanostructures play role of electro-catalysts. The composite of PPy-AuNPs was electrochemically synthesized on screen printed electrodes in single step and was characterized thoroughly using analytical techniques. The composite was used as matrix for immobilization of tyrosinase enzyme for tyrosine and catechin biosensing. The electrochemical measurements were performed using cyclic voltammetry (CV) and amperometry. For tyrosine, the composite based biosensor showed dynamic linearity from 10 to 100nM, having sensitivity of 1.0×10−2μAcm−2/nM, and LOD of 0.3nM. For catechin, the dynamic linearity range was from 1 to 20nM. The study showed that the biosensor exhibited more sensitivity towards tyrosine estimation as compared to catechin, which can be due to their structural difference. The biosensor was also used for sensing tyrosine and catechin in real samples and the study showed motivating results.

Fluorescence enhancement of organic chromophore in solid state via organic–inorganic hybrid matrix: Steady state and kinetic studies

Xerogels of silica-based organic–inorganic hybrid materials consisting of covalently bound fluorophores, terthiophene and terphenylene derivatives, were fabricated and analyzed. The synthesized chromophore-containing alkoxysilane derivatives were no emission in solid state, but showed strong fluorescence in organic–inorganic hybrid materials as well as in solution. Moreover, the fluorescence quantum yield of chromophore could be further improved in organic–inorganic hybrid materials with the optimized component than that of chromophore dissolved in solution. On the other hand, the fluorescence intensity of hybrid materials decreased with increasing the concentration of chromophore in organic–inorganic hybrid materials. Obviously, the relative distance between chromophores was shortened to perturb radiative relaxation. Temperature-dependent fluorescence spectra revealed that the fluorescence of chromophore in organic–inorganic hybrid materials was temperature-independent. This result indicated the inter-chromophore interactions and intra-molecular motion have been forbidden. The kinetic measurements confirmed that the chromophore spread in organic–inorganic hybrid materials was fixed with rigid conformation. The florescence decay lifetime of chromophore also kept similar at different temperature with organic–inorganic hybrid materials skeleton. This hybrid matrix provided a platform that enhanced fluorescence of chromophore in solid state at ambient temperature. Emission enhancement of organic chromophores, terthiophene and terphenylene, was performed through the utilization of covalently bound silica-based organic–inorganic hybrid material (OIHM). The chromophore was no emission in solid state, but showed strong fluorescence in OIHM as well as in solution. Moreover, the fluorescence quantum yield of chromophore could be better in OIHM with optimized component than that in solution. Temperature-dependent fluorescence spectra revealed that the fluorescence of chromophore in OIHM was temperature-independent. The kinetic measurements confirmed that the chromophore spread in OIHM was fixed with rigid conformation. This OIHM system offered a useful platform to maintain the emission behavior of organic chromophores in quasi-solid state.

Mechanisms of Polymer-Templated Nanoparticle Synthesis: Contrasting ZnS and Au.

We combine solution small-angle X-ray scattering (SAXS) and high-resolution analytical transmission electron microscopy (ATEM) to gain a full mechanistic understanding of substructure formation in nanoparticles templated by block copolymer reverse micelles, specifically poly(styrene)-block-poly(2-vinylpyridine). We report a novel substructure for micelle-templated ZnS nanoparticles, in which small crystallites (∼4 nm) exist within a larger (∼20 nm) amorphous organic-inorganic hybrid matrix. The formation of this complex structure is explained via SAXS measurements that characterize in situ for the first time the intermediate state of the metal-loaded micelle core: Zn(2+) ions are distributed throughout the micelle core, which solidifies as a unit on sulfidation. The nanoparticle size is thus determined by the radius of the metal-loaded core, rather than the quantity of available metal ions. This mechanism leads to particle size counterintuitively decreasing with increasing metal content, based on the modified interactions of the metal-complexed monomers in direct contrast to gold nanoparticles templated by the same polymer.

Enhanced Electrochemical Stability of Quasi-Solid-State Electrolyte Containing SiO2 Nanoparticles for Li-O2 Battery Applications.

A stable electrolyte is required for use in the open-packing environment of a Li-O2 battery system. Herein, a gelled quasi-solid-state electrolyte containing SiO2 nanoparticles was designed, in order to obtain a solidified electrolyte with a high discharge capacity and long cyclability. We successfully fabricated an organic-inorganic hybrid matrix with a gelled structure, which exhibited high ionic conductivity, thereby enhancing the discharge capacity of the Li-O2 battery. In particular, the improved electrochemical stability of the gelled cathode led to long-term cyclability. The organic-inorganic hybrid matrix with the gelled structure played a beneficial role in improving the ionic conductivity and long-term cyclability and diminished electrolyte evaporation. The experimental and theoretical findings both suggest that the preferential binding between amorphous SiO2 and polyethylene glycol dimethyl ether (PEGDME) solvent led to the formation of the solidified gelled electrolyte and improved electrochemical stability during cycling, while enhancing the stability of the quasi-solid state Li-O2 battery.