Organic Shell Research Articles

Simultaneous construction of impermeable dual-shell stabilizing fluoride phosphors for white light-emitting diodes

The traditional strategy to improve material stability is to cover the surface with a shell to resist adverse environmental factors. For the red-emitting fluoride materials with easily hydrolyzed Mn4+ on the surface, many strategies have been reported with limited effectiveness. In this work, simultaneous construction of an impermeable dual-shell on Mn4+-doped fluoride is proposed to solve the instability problem by a simple pyruvic acid (PA) treatment. The internal quantum efficiency of the K2SiF6:Mn4+ with dual-shell can be optimized up to 99.71%, the photoluminescence intensity can maintain 88.5% of the original intensity after soaking in water for 360 h, and the body color is not changed even in boiling. The reduction effect of the PA solution builds a hard fluoride shell by removal of the surface Mn4+, and the hydrogen bonding effect of PA molecular leads to the formation of a soft organic shell. The dual-shell can effectively block the damage of fluoride by external water molecules and achieve a significant improvement in water stability. The dual effect of PA is derived from its special molecular structure containing α-ketone carbonyl and carboxyl groups. This hypothesis is supported by the results of the moisture resistance of fluoride-treated with a variety of solvents similar in molecular structure to PA. In addition, DFT calculations simulated various hydrogen bond structures that may be formed between PA molecules and fluoride surface atoms.

Fabrication of a magnetic nanocarrier for doxorubicin delivery based on hyperbranched polyglycerol and carboxymethyl cellulose: An investigation on the effect of borax cross-linker on pH-sensitivity

A new core-shell pH-responsive nanocarrier was prepared based on magnetic nanoparticle (MNP) core. Magnetic nanoparticles were first modified with hyperbranched polyglycerol as the first shell. Then the magnetic core was decorated with doxorubicin anticancer drug (DOX) and covered with PEGylated carboxymethylcellulose as the second shell. Borax was used to partially cross-link organic shells in order to evaluate drug loading content and pH-sensitivity. The structure of nanocarrier, organic shell loadings, magnetic responsibility, morphology, size, dispersibility, and drug loading content were investigated by IR, NMR, TG, VSM, XRD, DLS, HR-TEM and UV–Vis analyses. In vitro release investigations demonstrated that the use of borax as cross-linker between organic shells make the nanocarrier highly sensitive to pH so that more that 70% of DOX is released in acidic pH. A reverse pH-sensitivity was observed for the nanocarrier without borax cross-linker. The MTT assay determined that the nanocarrier exhibited excellent biocompatibility toward normal cells (HEK-293) and high toxicity against cancerous cells (HeLa). The nanocarrier also showed high hemocompatibility. Cellular uptake revealed high ability of nanocarrier toward HeLa cells comparable with free DOX. The results also suggested that low concentration of nanocarrier has a great potential for use as contrast agent in magnetic resonance imaging (MRI).

Mechanics under pressure of gold nanoparticle supracrystals: the role of the soft matrix.

We report on High Pressure Small Angle X-ray Scattering (HP-SAXS) measurements on 3D face-centered cubic (FCC) supracrystals (SCs) built from spherical gold nanoparticles (NPs). Dodecane-thiol ligands are grafted on the surface and ensure the stability of the gold NPs by forming a protective soft layer. Under a hydrostatic pressure of up to 12 GPa, the SC showed a high structural stability. The bulk elastic modulus of the SC was derived from the HP-SAXS measurements. The compression of the SC undergoes two stages: the first one related to the collapse of the voids between the NPs followed by the second one related to the compression of the soft matrix which gives a major contribution to the mechanical behavior. By comparing the bulk modulus of the SC to that of dodecane, the soft matrix appears to be less compressible than the crystalline dodecane. This effect is attributed to a less optimized chain packing under pressure compared to the free chains, as the chains are constrained by both grafting and confinement within the soft matrix. We conclude that these constraints on chain packing within the soft matrix enhance the stability of SCs under pressure.

ZIF-Mediated Gold Nanorod Assembly for Surface-Enhanced Raman Scattering Detection of 4-Nitrobenzenethiol

Nanoparticle assemblies exhibit unique properties compared to single entities due to interactions between their building blocks. Although the development of large-area assemblies has been extensively studied, finite nanoparticle assemblies with tens of building blocks have not been adequately explored. Here, we prepared a finite assembly of anisotropic gold nanorods through encapsulation by a zeolitic imidazolate framework-8 (ZIF). The three-dimensional reconstruction of the ZIF-encapsulated nanorod assembly indicated that the assembled nanorods are separate bundles aligned side-by-side, each of which serves as a nucleation center for a cube-shaped ZIF domain. Further experiments showed that the assembly pattern and the shell dimension can be controlled by the cysteamine and surfactant concentrations. Moreover, the ZIF-encapsulated nanorod assembly had twice the surface-enhanced Raman scattering signal of a single nanorod and showed higher selectivity for 4-nitrobenzenethiol versus rhodamine 6G. Our model system will significantly contribute to the development of finite anisotropic nanoparticle assemblies with microporous metal–organic framework shells and extend their applicability.

Organic Coating Reduces Hygroscopic Growth of Phase-Separated Aerosol Particles

A large fraction of secondary aerosol particles are liquid-liquid phase-separated with an organic shell and an inorganic core. This has the potential to regulate the hygroscopicity of such particles, with significant implications for their optical properties, reactivity, and lifetime. However, it is unclear how this phase separation affects the hygroscopic growth of the particles. Here, we showed a large variation in hygroscopic growth (e.g., 1.14-1.32 under a relative humidity (RH) of 90%) of particles from the forest and urban atmosphere, which had different average core-shell ratios. For this reason, a controlled laboratory experiment further quantifies the impact of the organic shell on particle growth with different RH values. Laboratory experiments demonstrated that (NH4)2SO4 particles with thicker secondary organic shells have a lower growth factor at an RH below 94%. Organic shells started to deliquesce first (RH > 50%) and the phase changes of sulfate cores from solid to liquid took place at an RH higher than 80% as deliquescence relative humidity of pure (NH4)2SO4. Our study provides the first direct evidence on an individual particle basis that hygroscopic growth behavior of phase-separated particles is dependent on the thickness of organic shells, highlighting the importance of organic coating in water uptake and possible heterogeneous reactions of the phase-separated particles.

The flame retardant and thermal conductivity properties of high thermal conductivity expandable graphite microcapsule filled natural rubber composites

The flammable feature limits the application of natural rubber in building fields. Although expandable graphite (EG) microcapsule has good compatibility with natural rubber (NR), the organic wall material of microcapsule has the disadvantage of low thermal conductivity and increases the risk of combustion of NR. In this study, EG microcapsule was prepared via in-situ polymerization (BN-PMEG) whilst its organic shell with high compatibility and thermal conductivity was developed by boron nitride (BN)-doped. The composite structure and thermal performances were analyzed via scanning electron microscope test (SEM), Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TG). Following this, the cone calorimeter test, limiting oxygen index test, vertical burning test, time to ignition test, tensile strength and fracture test were used to describe the fire behavior and mechanical properties. The results indicate that the BN is embedded in the PMMA shell and the diameter of BN-PMEG is 20–50 μm. According to the mechanical property and thermal conductivity test, BN-PMEG have better compatibility with NR than expansible graphite and increases the thermal conductivity of NR composites. Our work provides a new choice for designing and applying rubber composite materials in buildings.

The thermal behavior and flame retardant performance of phase change material microcapsules with modified carbon nanotubes

The organic shell materials and phase change material (PCM) show the drawbacks of low thermal conductivity, poor thermal stability and flammability, restricting the application of the PCM microcapsules. A novel Fe3O4/carbon nanotubes (CNTs) modified PCM microcapsule (Fe–C-PCM) was successfully fabricated by the in-situ polymerization method and applied in the rigid polyurethane foam (RPUF-Fe-C-PCM) in this study. The results indicated that Fe3O4 microspheres with a diameter of about 200 nm were formed on CNTs. The thermostability of Fe–C-PCM was better than that of normal PCM microcapsules, which was proved by the results of TGA and MCC. The DSC results showed that the CNTs in Fe–C-PCM acted as internal and external heat transfer channels to ameliorate the thermal conductivity of PMMA. The results of cone calorimeter test indicated that RPUF-Fe-C-PCM had large inhibitory effect on the heat and smoke release of composite during the combustion process. The test results from small room model test and infrared thermal imager suggested that RPUF-Fe-C-PCM kept the indoor temperature stable within a certain range and exhibited excellent ability to absorb/release heat. These properties will greatly promote the application of Fe–C-PCM in insulation materials.

Molecular-scale description of interfacial mass transfer in phase-separated aqueous secondary organic aerosol

Abstract. Liquid–liquid phase-separated (LLPS) aerosol particles are known to exhibit increased cloud condensation nuclei (CCN) activity compared to well-mixed ones due to a complex effect of low surface tension and non-ideal mixing. The relation between the two contributions as well as the molecular-scale mechanism of water uptake in the presence of an internal interface within the particle is to date not fully understood. Here we attempt to gain understanding in these aspects through steered molecular dynamics simulation studies of water uptake by a vapor–hydroxy-cis-pinonic acid–water double interfacial system at 200 and 300 K. Simulated free-energy profiles are used to map the water uptake mechanism and are separated into energetic and entropic contributions to highlight its main thermodynamic driving forces. Atmospheric implications are discussed in terms of gas–particle partitioning, intraparticle water redistribution timescales and water vapor equilibrium saturation ratios. Our simulations reveal a strongly temperature-dependent water uptake mechanism, whose most prominent features are determined by local extrema in conformational and orientational entropies near the organic–water interface. This results in a low core uptake coefficient (ko/w=0.03) and a concentration gradient of water in the organic shell at the higher temperature, while entropic effects are negligible at 200 K due to the association-entropic-term reduction in the free-energy profiles. The concentration gradient, which results from non-ideal mixing – and is a major factor in increasing LLPS CCN activity – is responsible for maintaining liquid–liquid phase separation and low surface tension even at very high relative humidities, thus reducing critical supersaturations. Thermodynamic driving forces are rationalized to be generalizable across different compositions. The conditions under which single uptake coefficients can be used to describe growth kinetics as a function of temperature in LLPS particles are described.

Compatible paraffin@SiO2 microcapsules/polydimethylsiloxane composites with heat storage capacity and enhanced thermal conductivity for thermal management

Integrating phase change materials (PCMs) with polymers is expected to develop novel polymeric composites with heat storage capacity, thus showing potential applications in thermal management. Microencapsulation of solid-liquid PCMs by organic or inorganic shells can effectively prevent liquid leakage from the PCMs, thereby improving their application performance. Herein, phase change microcapsules with SiO2 shell were combined with polydimethylsiloxane (PDMS) to construct a novel kind of polymeric composite. It is shown that an interfacial interaction between the paraffin@SiO2 microcapsules and the PDMS occurs, which endows the two components with good compatibility. The paraffin@SiO2 microcapsules/PDMS composites exhibit slightly higher phase change temperatures than those of the microcapsules. The mass fraction of the microcapsules in the PDMS-based composites can reach 38.89 wt%, at which a latent heat value of 60.61 J/g is achieved, together with an enhancement by 80.71% in thermal conductivity as compared to that of pure PDMS. When the paraffin@SiO2 microcapsules/PDMS composite was employed for chip thermal management, the chip temperature reduced by 15.87%, compared with that using the one without any phase change microcapsules. It is revealed that the paraffin@SiO2 microcapsules/PDMS composites possess good thermal reliability. These merits make the paraffin@SiO2 microcapsules/PDMS composites show great promise in practical applications.

Cd-Doped Polyoxotitanium Nanoclusters with a Modifiable Organic Shell for Photoelectrochemical Water Splitting.

Incorporating heterometal and chromogenic groups into the titanium oxo cluster (TOC) nanomaterials is one of the effective strategies for the development of new high-performance photoelectrically active materials. In this Article, we report the structures and photoelectrochemical (PEC) performances of a family of TOCs, including pure [Ti12O8(OEt)16L8] ({Me-Ti12}) and six Cd-doped clusters formulated as [H4Cd2Ti10O8(OEt)16(L)8(H2O)2] ({Cd2Ti10}; L = salicylic acid and their derivatives). The six Cd-doped clusters are isostructural, containing the same {Cd2Ti10O8} core, but are protected by salicylic ligands modified with different functional groups. The compositions, structures, and solution stability of these clusters have been studied in detail by single-crystal X-ray diffraction and electrospray ionization mass spectrometry measurements. The embedding of heterometallic Cd(II) and chemical modification of organic protective shells can effectively regulate the PEC water oxidation activity of those clusters, with {F-Cd2Ti10} having the highest turnover number of 518.55 and the highest turnover frequency of 172.85 h-1. Our work highlights the potential of using TOCs that do not contain noble metals as water oxidation catalysts, and their catalytic activity can be regulated by structural modification.

Magnetic composite of \u03b3-Fe2O3 hollow sphere and palladium doped nitrogen-rich mesoporous carbon as a recoverable catalyst for C\u2013C coupling reactions

In this article, palladated-magnetic nitrogen doped porous carbon was prepared from nano magnetic γ-Fe2O3 hollow sphere (h-Fe2O3) with high specific surface area and pore volume. To the purpose, initially h-Fe2O3 was prepared and covered with glucose via hydrothermal treatment with subsequent polymerization of organic shell. The polymerization of melamine-resorcinol–formaldehyde (MRF) was achieved in the presence of Cl-functionalized glucose coated h-Fe2O3 (h-Fe2O3@glu-MRF). Next, the prepared magnetic core–shell hollow sphere was palladated followed by carbonization to yield Pd@h-Fe2O3@C introducing more pores in its structure. The resulted compound, Pd@h-Fe2O3@C, was fully characterized, showing that carbonization process expressively increased the specific surface area. The resulted Pd@h-Fe2O3@C was successfully used for promoting C–C coupling reactions under mild reaction conditions as a heterogeneous catalyst and its activity was compared with some prepared control catalysts. This novel catalyst was magnetically separated simply by a magnet bar and recycled and reused at least in five consecutive runs, without considerable loss of its activity. It is note mentioning that, high recyclability with low Pd leaching are another gains of this protocol.

Hybrid Inorganic-Organic Core-Shell Nanodrug Systems in Targeted Photodynamic Therapy of Cancer.

Hybrid inorganic-organic core-shell nanoparticles (CSNPs) are an emerging paradigm of nanodrug carriers in the targeted photodynamic therapy (TPDT) of cancer. Typically, metallic cores and organic polymer shells are used due to their submicron sizes and high surface to volume ratio of the metallic nanoparticles (NPs), combined with enhances solubility, stability, and absorption sites of the organic polymer shell. As such, the high loading capacity of therapeutic agents such as cancer specific ligands and photosensitizer (PS) agents is achieved with desired colloidal stability, drug circulation, and subcellular localization of the PS agents at the cancer site. This review highlights the synthesis methods, characterization techniques, and applications of hybrid inorganic-organic CSNPs as loading platforms of therapeutic agents for use in TPDT. In addition, cell death pathways and the mechanisms of action that hybrid inorganic-organic core-shell nanodrug systems follow in TPDT are also reviewed. Nanodrug systems with cancer specific properties are able to localize within the solid tumor through the enhanced permeability effect (EPR) and bind with affinity to receptors on the cancer cell surfaces, thus improving the efficacy of short-lived cytotoxic singlet oxygen. This ability by nanodrug systems together with their mechanism of action during cell death forms the core basis of this review and will be discussed with an overview of successful strategies that have been reported in the literature.

Inorganic-organic nanocomposite networks: Structure, curing reaction, properties, and hard coating performance

This study reports the first structure and morphology details of octakis(acryloyloxypropyl)-octasilsesquioxane (POSS-Acryl8), a reactive inorganic-organic hybrid molecule, before and after photochemically crosslinked. POSS-Acryl8 was confirmed as an oblate ellipsoidal nanoparticle consisting of inorganic cage core (0.774 nm diameter) and chemically-bonded organic shell (1.447 nm thickness). The core volume fraction is only 0.95% in a single molecule, but drastically increases up to 18.8% in the neat bulk state and 31.9% in the photocured film state; the individual inorganic cores are eventually encapsulated with the networked shells (0.176 nm thickness) chemically interconnected with the neighbors. Based on such the highly networked structure and inorganic core reinforcement, the photocured POSS-Acryl8 exhibited exceptionally high optical transparency, glass transition temperature, surface hardness, and abrasion resistances. Due to the superior properties, clear hard POSS-Acryl8 coatings solved completely inherently poor surface hardness and abrasion resistances of conventional polymer window substrates and, furthermore, serious drawbacks in the eraser and steel wool abrasion resistances of glass window substrate. In addition, POSS-Acryl8 was found miscible with pentaerythritolylethyl tetraacrylate (PEEO-Acryl4) and thereby enhanced substantially the surface hardness and abrasion resistances of PEEO-Acryl4 through nanocomposite network formations. It turns out that the photocurable inorganic-organic POSS-Acryl8 hybrid and its composites with fully organic PEEO-Acryl4 are so suitable for optically clear hard top coating applications in advanced telecommunication, defense, automobile, and smart home appliance (smart and foldable phones, display devices, sensor windows, etc.).

Design and fabrication of hybrid triple-responsive κ-carrageenan-based nanospheres for controlled drug delivery

In the last two decades, the utilization of magnetic nanospheres in intelligent polymeric structures have received increased attention of researchers in numerous biomedical applications. Here, hybrid nanostructured triple-responsive magnetic nanospheres (κ-Car-g-P(AA/DMA)@Fe3O4) containing inorganic iron oxide core (Fe3O4) and organic graft copolymeric shell based on κ-carrageenan (κ-Car) and poly(acrylic acid/dimethylaminoethyl methacrylate) (P(AA/DMA)) were synthesized by microwave induced co-precipitation technique. The structure, size, surface morphology, magnetic property and stability of synthesized κ-Car-g-P(AA/DMA)@Fe3O4 magnetic nanospheres were characterized using FTIR, UV, XRD, TEM, Zeta-sizer, and VSM. κ-Car-g-P(AA/DMA)@Fe3O4 nanospheres were loaded with 5-Fluorouracil (5-FU) as an antineoplastic drug, and their 5-FU release behavior was explored in diverse graft yields, pH values, temperatures and in the existence of an alternating magnetic field. The κ-Car-g-P(AA/DMA)@Fe3O4 nanospheres demonstrated pH-, thermo-, and magnetic field-responsive 5-FU release with good biocompatibility and excellent anticancer activity. In addition, 5-FU release under 50 mT magnetic field reached to 100% within 4 h. This work exhibits that hybrid nanospheres have a triple stimuli-responsive influence, which is of principal importance for the future design and application of multi-functional responsive platforms to develop externally stimulated release of active agents and their healthcare capability.

Pengaruh Pemberian Pupuk Organik Cair Cangkang Telur Ayam Boiler dan Pupuk Anorganik Urea Terhadap Pertumbuhan dan Hasil Tanaman Bayam Merah (Amaranthus tricolor L.) Varietas Mira.

Red spinach is a vegetable plant that has high economic value and is usually consumed by the leaves. In 2019 there was a decrease caused by the lack of soil fertility so that to increase production, it could improve soil fertility by means of fertilization.The purpose of this study was to obtain the optimal combination dose of organic chicken eggshell fertilizer from inorganic urea fertilizer on the growth and yield of red spinach (Amaranthus tricolor L.) mira variety. The research was carried out from June to July 2021, on the exact land in Pasir jengkol Village, Majalaya District, Karawang Regency, West Java. The research method used was factorial randomized block design (RAK), the first factor was liquid organic fertilizer chicken egg shells (C) consisting of 3 levels: c0 (0 ml/L), c1 (30 ml/L), c2 (60 ml/L). L) and the second factor of inorganic fertilizer urea (u) consists of 3 levels: u0 (0 kg/ha), u1 (50 kg/ha), u2 (100 kg/ha).There were 9 treatments with 3 replications so there were 27 experimental units. The results showed that there was no interaction between the addition of liquid organic fertilizer chicken egg shells with inorganic fertilizers on the growth and yield of red spinach (Amaranthus tricolor L.) mira variety. There was no one dose of inorganic urea fertilizer that provided optimal growth and yield of red spinach (Amaranthus tricolor L.) mira variety for each dose of liquid organic fertilizer given chicken egg shells.

Preparation of core‐shell microporous organic polymer‐coated silica microspheres for chromatographic separation and N‐glycopeptides enrichment

Through a "one-pot" strategy, a layer of microporous organic polymer was coated onto the surface of monodisperse amino-functionalized silica microsphere via amino-aldehyde condensation reaction with core-shell structure. The change in chemical structure of material before and after modification was determined by Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy. Due to existence of a large number of amino and aldehyde groups in microporous organic polymer shell, the water contact angle decreased from 56.8° (silica microspheres) to 34.7° (microporous organic polymer-coated silica microspheres). Based on these properties, microporous organic polymer-coated silica microspheres were employed as the stationary phase for capillary liquid chromatography and successfully offered baseline separation of polar small molecules. Additionally, the material could also be served as the sorbent of hydrophilic interaction chromatography to enrich glycopeptides from human serum digest. A total of 470 unique N-glycopeptides and 342 N-glycosylation sites mapped to 112 N-glycosylated proteins were unambiguously identified from 2μL of human serum, exhibiting a promising application prospect of microporous organic polymer-coated silica microspheres in the pretreatment of proteomics samples.

Photoechogenic Inflatable Nanohybrids for Upconversion-Mediated Sonotheranostics.

Hybrid nanostructures are promising for ultrasound-triggered drug delivery and treatment, called sonotheranostics. Structures based on plasmonic nanoparticles for photothermal-induced microbubble inflation for ultrasound imaging exist. However, they have limited therapeutic applications because of short microbubble lifetimes and limited contrast. Photochemistry-based sonotheranostics is an attractive alternative, but building near-infrared (NIR)-responsive echogenic nanostructures for deep tissue applications is challenging because photolysis requires high-energy (UV-visible) photons. Here, we report a photochemistry-based echogenic nanoparticle for in situ NIR-controlled ultrasound imaging and ultrasound-mediated drug delivery. Our nanoparticle has an upconversion nanoparticle core and an organic shell carrying gas generator molecules and drugs. The core converts low-energy NIR photons into ultraviolet emission for photolysis of the gas generator. Carbon dioxide gases generated in the tumor-penetrated nanoparticle inflate into microbubbles for sonotheranostics. Using different NIR laser power allows dual-modal upconversion luminescence planar imaging and cross-sectional ultrasonography. Low-frequency (10 MHz) ultrasound stimulated microbubble collapse, releasing drugs deep inside the tumor through cavitation-induced transport. We believe that the photoechogenic inflatable hierarchical nanostructure approach introduced here can have broad applications for image-guided multimodal theranostics.

Protection of Ag Clusters by Metal-Oxo Modules.

Monodisperse and atomically precise Ag nanoclusters have attracted considerable recent research interest. A conventional silver cluster usually consists of a silver metallic kernel and an organic peripheral ligand shell. Nevertheless, the present inevitable problem is the unsatisfied stability of such nanoclusters. In this concept, we will give an introduction to Ag clusters protected by metal-oxo modules, which exhibit enhanced stability and unique properties. Accordingly, three different types of clusters are summarized: (1) Ag clusters protected by mononuclear oxometallates; (2) Ag clusters protected by block-like metal-oxo clusters; (3) Ag clusters protected by hollow-like metal-oxo clusters. The aim of this concept is to offer possible general guidance and insight into future rational design of more metal-oxo clusters protected silver clusters or even other coinage metal nanoclusters.

Plasmon-Driven Interfacial Catalytic Reactions in Plasmonic MOF Nanoparticles.

Benefiting from the noble metal nanoparticle core and organic porous nanoshell, plasmonic metal-organic frameworks (MOFs) become a nanostructure with great enhancement of the electromagnetic field and a high density of reaction sites, which has fantastic optical properties in surface plasmon-related fields. In this work, the plasmon-driven interfacial catalytic reactions involving p-aminothiophenol to 4,4'-dimercaptoazobenzene (trans-DMAB) in both the liquid and gaseous phases are studied in plasmonic MOF nanoparticles, which consist of a Ag nanoparticle core and an organic shell (ZIF-8). The surface-enhanced Raman spectroscopy (SERS) spectra recorded at the plasmonic MOF in an aqueous environment demonstrate that the reversible plasmon-driven interfacial catalytic reactions could be modulated by a reductant (NaBH4) or oxidant (H2O2). Also, the situ SERS spectra also point out that plasmonic MOF (AgNP@ZIF-8) nanoparticles exhibit much better catalytic performance in the H2O2 solution compared to pure Ag nanoparticles for the anti-oxidation caused by the MOF shell. It is surprising that although there is greater SERS enhancement obtained at pure Ag nanoparticles, the plasmon-driven interfacial catalytic reactions only occur at plasmonic AgNP@ZIF-8 nanoparticles in the gaseous phase. This interesting phenomenon is further confirmed and analyzed by simulated electromagnetic field distributions, which could be understood by the effective capture of gaseous molecules by the organic porous nanoshell. Our work not only explores the plasmonic MOF nanoparticles with unique optical properties but also strengthens the understanding of plasmon-driven interfacial catalytic reactions.

Iron Oxide/Polymer Core-Shell Nanomaterials with Star-like Behavior.

Embedding nanoparticles (NPs) with organic shells is a way to control their aggregation behavior. Using polymers allows reaching relatively high shell thicknesses but suffers from the difficulty of obtaining regular hybrid objects at gram scale. Here, we describe a three-step synthesis in which multi-gram NP batches are first obtained by thermal decomposition, prior to their covalent grafting by an atom transfer radical polymerization (ATRP) initiator and to the controlled growing of the polymer shell. Specifically, non-aggregated iron oxide NPs with a core principally composed of γ-Fe2O3 (maghemite) and either polystyrene (PS) or polymethyl methacrylate (PMMA) shell were elaborated. The oxide cores of about 13 nm diameter were characterized by dynamic light scattering (DLS), transmission electron microscopy (TEM), and small-angle X-ray scattering (SAXS). After the polymerization, the overall diameter reached 60 nm, as shown by small-angle neutron scattering (SANS). The behavior in solution as well as rheological properties in the molten state of the polymeric shell resemble those of star polymers. Strategies to further improve the screening of NP cores with the polymer shells are discussed.