Hybrid Organic–Inorganic Colloidal Composite ‘Sponges’ via Internal Crosslinking

An effective method for the generation of hybrid organic–inorganic nanocomposite microparticles featuring controlled size and high structural stability is presented. In this process, an oil‐in‐water Pickering emulsion is formed using hydrophilic amine‐functionalized silica nanoparticles. Covalent modification using a hydrophobic maleic anhydride copolymer then alters nanoparticle wettability during crosslinking, causing a core‐shell to nanocomposite structural reorganization of the assemblies. The resulting porous nanocomposites maintain discrete microparticle structures and retain payloads in their oil phase even when incubated in competitive solvents such as ethanol.     

Model polymer nanocomposites provide an understanding of confinement effects in real nanocomposites

Owing to the improvement of properties including conductivity, toughness and permeability, polymer nanocomposites are slated for applications ranging from membranes to fuel cells. The enhancement of polymer properties by the addition of inorganic nanoparticles is a complex function of interfacial interactions, interfacial area and the distribution of inter-nanofiller distances. The latter two factors depend on nanofiller dispersion, making it difficult to develop a fundamental understanding of their effects on nanocomposite properties. Here, we design model poly(methyl methacrylate)-silica and poly(2-vinyl pyridine)-silica nanocomposites consisting of polymer films confined between silica slides. We compare the dependence of the glass-transition temperature (Tg) and physical ageing on the interlayer distance in model nanocomposites with the dependence of silica nanoparticle content in real nanocomposites. We show that model nanocomposites provide a simple way to gain insight into the effect of interparticle spacing on Tg and to predict the approximate ageing response of real nanocomposites.     

Ultrasound-induced capping of polystyrene on TiO2 nanoparticles by precipitation with compressed CO2 as antisolvent

In this work, a route for the synthesis of inorganic/polymer core/shell composite nanoparticles was proposed, which can be called the antisolvent-ultrasound method. Compressed CO2 was used as antisolvent to precipitate the polymer from its solution dispersed with inorganic nanoparticles, during which ultrasonic irradiation was used to induce the coating of precipitated polymers on the surfaces of the inorganic nanoparticles. TiO2/polystyrene (PS) core/shell nanocomposites have been successfully prepared using this method. The transmission electronic micrographs (TEM) of the obtained nanocomposites show that the TiO2 nanoparticles are coated by the PS shells, of which the thickness can be tuned by the pressure of CO2. The phase structure, absorption properties, and thermal stability of the composite were characterized by X-ray diffraction (XRD), UV-vis spectra, and thermogravimetry, respectively. The results of X-ray photoelectron spectra (XPS) indicate the formation of a strong interaction between PS and TiO2 nanoparticles in the resultant products. This method has some potential advantages for applications and may be easily applied to the preparation of a range of inorganic/polymer core/shell composite nanoparticles.     

Preparation of multilayered organic-inorganic hybrid core-shell particles by stepwise surface formation

This paper introduces a stepwise formation method for micro-sized, multilayered core-shell particles comprising an inorganic core, organic inner shell, and inorganic outer shell. A silica core was coated with a polystyrene seed layer, followed by surface seed polymerization with styrene, to afford the inner shell. These particles were then coated with a silica outer shell by a surface sol-gel reaction with tetraethoxysilane. The versatility of this combined surface seed polymerization and sol-gel method is emphasized by the precise control achieved over particle diameter as well as shell thickness and count. Moreover, the organic inner shell can be readily eliminated to afford a single-core-containing micro-capsular structure.     

可控制备磁性四氧化三铁-金纳米复合颗粒及其催化性能研究

随着纳米催化剂的不断发展, 基于纳米金的多功能复合材料以其高效的催化性能而受到广泛关注。本研究采用简单可控的原位还原法, 制备了一种粒径均一、分散性良好、可快速磁分离且具有高催化活性与催化稳定性的磁性四氧化三铁-金纳米复合颗粒。首先用有机硅源-巯丙基三乙氧基硅烷(MPTES)水解得到的有机硅层来包覆粒径约100 nm的亲水四氧化三铁(Fe₃O₄)纳米颗粒, 再通过有机硅层表面的巯基来锚定原位还原生成的尺寸可控的金纳米颗粒(2 nm或6 nm), 得到内核为四氧化三铁、壳层为金纳米颗粒均匀修饰有机硅层的磁性氧化硅复合颗粒。利用透射电子显微镜(TEM)、动态光散射仪(DLS)和振动样品磁强计(VSM)等对所合成材料进行系统表征, 结果表明: 合成的磁性氧化硅复合颗粒核壳结构明显, 分散性良好, 粒径约为150 nm; 饱和磁强度为32.1 A•m²/kg, 具有良好的超顺磁特性。将其应用于4-硝基苯酚的催化还原, 转化频率(TOF)值高达70 s^-1, 远高于文献报道值, 五次循环反应后的转化率依然高达98%, 证实其具备高催化活性及良好的循环催化性能。     

纳米银镓合金/聚甲基丙烯酸甲酯复合粒子的结构表征

在不加任何引发剂和金属还原剂的条件下, 超声辐射双原位引发乳液聚合制备纳米银镓合金/聚甲基丙烯酸甲酯(Ag-Ga/PMMA)复合粒子。利用HREM、 EDS、 XRD等对复合粒子进行了分析, 表明所制得的乳胶粒子具有典型的核壳结构, 粒径为80~200nm, 分布均匀, 单分散性好, 基本没有出现团聚。乳胶粒子中成壳部分的聚合物产生了一层层有序组装的现象。XRD证明, 有纳米合金Ag_0.72Ga_0.28存在; 此外还出现了2个新的衍射峰, 推断可能是新的银镓合金物质。      

Fabrication of hollow polyelectrolyte nanospheres via surface-initiated atom transfer radical polymerization

Novel polyelectrolyte-grafted core-shell organic/inorganic hybrid nanospheres which possess hard backbone of silica nanoparticles and soft shell of cross-linked poly(ionic liquids) (PILs) have been synthesized via a surface-initiated atom transfer radical polymerization (SI-ATRP). After removal of the core templates of the core-shell nanospheres, nearly monodispersed hollow polyelectrolyte nanospheres were obtained. Various characterization techniques including FT-IR, XPS, and TEM were used to characterize the resulting core-shell and hollow polyelectrolyte nanospheres. The results showed that the hollow nanosphere has a hollow core of an average diameter of ca. 200 nm with a shell thickness of ca. 25 nm. The obtained hollow polyelectrolyte nanospheres could be applied in release-control systems.     

硅丙乳液包覆Mg(OH)2核壳结构纳米粒子的制备与表征

为有效提高Mg(OH)_2纳米粒子在硅丙乳液中的相容性与分散稳定性,在油酸修饰Mg(OH)_2纳米粒子的基础上,以甲基丙烯酸甲酯、丙烯酸丁酯、丙烯酸与乙烯基三乙氧基硅烷为共聚单体,通过乳液聚合法制备出具有核壳结构的硅丙乳液包覆Mg(OH)_2复合材料。利用傅里叶变换红外光谱仪(FTIR)、X射线衍射仪(XRD)、透射电子显微镜(TEM)等测试手段对样品结构、形貌进行了表征。通过燃烧实验,研究了硅丙乳液包覆Mg(OH)_2纳米粒子对水性防火涂料阻燃性能的影响。结果表明,油酸通过酯化作用修饰在Mg(OH)_2纳米粒子表面,借助油酸分子中双键结构,丙烯酸类混合单体在纳米Mg(OH)_2表面完成聚合过程,形成以Mg(OH)_2纳米粒子为核、硅丙乳液为壳的复合材料。XRD与热分析表明经硅丙乳液包覆的纳米Mg(OH)_2晶体结构与热稳定性能未受影响。此外,掺杂0.1%(质量分数)的硅丙乳液包覆Mg(OH)_2可使水性防火涂料阻燃时间延长至113 min,较未掺杂水性涂料阻燃时间(91min)提高约23%。     

Design of Multifunctional Fluorescent Hybrid Materials Based on SiO2 Materials and Core–Shell Fe3O4@SiO2 Nanoparticles for Metal Ion Sensing

Hybrid fluorescent materials constructed from organic chelating fluorescent probes and inorganic solid supports by covalent interactions are a special type of hybrid sensing platform that has gained much interest in the context of metal ion sensing applications owing to their excellent advantages, recyclability, and solubility/dispersibility in particular, as compared with single organic fluorescent molecules. In recent decades, SiO₂ materials and core–shell Fe₃O₄@SiO₂ nanoparticles have become important inorganic solid materials and have been used as inorganic solid supports to hybridize with organic fluorescent receptors, resulting in multifunctional fluorescent hybrid systems for potential applications in sensing and related research fields. Therefore, recent progress in various fluorescent‐group‐functionalized SiO₂ materials is reviewed, with a focus on mesoporous silica nanoparticles and core–shell Fe₃O₄@SiO₂ nanoparticles, as interesting fluorescent organic–inorganic hybrid materials for sensing applications toward essential and toxic metal ions. Selective examples of other types of silica/silicon materials, such as periodic mesoporous organosilicas, solid SiO₂ nanoparticles, fibrous silica spheres, silica nanowires, silica nanotubes, and silica hollow microspheres, are also mentioned. Finally, relevant perspectives of metal‐ion‐sensing‐oriented silica‐fluorescent probe hybrid materials are provided.     

Structure characterization of Ag-Ga/poly(methyl methacrylate) nanoparticles

The Ag-Ga/poly(methyl methacrylate) nanoparticles were prepared in-situ by emulsion polymerization method under ultrasonic irradiation without any initiators or metal reductant. HRTEM, EDS and XRD experiments were performed to characterize the nanoparticles. The results indicated that the nanocomposite particles possessed core-shell structure with diameters of 80-200 nm, as well as excellent monodispersity. The phenomenon that the polymer forms the shell via layer-by-layer self-assembly was found. XRD proved the existence of Ag0.72Ga0.28 and the probability of new Ag-Ga alloy because of two unknown diffraction peaks.     

Strawberry‐like Core–Shell Ag@Polydopamine@BaTiO3 Hybrid Nanoparticles for High‐k Polymer Nanocomposites with High Energy Density and Low Dielectric Loss

Flexible nanocomposites comprising of polymer and high‐dielectric‐constant (high‐k) ceramic nanoparticles are becoming increasingly attractive for dielectric and energy storage applications in modern electronic and electric industry. However, a huge challenge still remains. Namely, the increase of dielectric constant usually at the cost of significant decrease of breakdown strength of the nanocomposites because of the electric field distortion and concentration induced by the high‐k filler. To address this long‐standing problem, by using nano‐Ag decorated core–shell polydopamine (PDA) coated BaTiO₃ (BT) hybrid nanoparticles, a new strategy is developed to prepare high‐k polymer nanocomposites with high breakdown strength. The strawberry‐like BT‐PDA‐Ag based ferroelectric polymer [i.e., poly(vinylideneflyoride‐co‐hexafluroro propylene), P(VDF‐HFP)] nanocomposites exhibit greatly enhanced energy density and significantly suppressed dielectric loss as well as leakage current density in comparison with the nanocomposites with the core–shell structured BT‐PDA. Coulomb‐blockade effect of super‐small nano‐Ag is used to explain the observed performance enhancement of the nanocomposites. The simplicity and scalability of the described approach provide a promising route to polymer nanocomposites for dielectric and energy storage applications.     

Organic-dye-coupled magnetic nanoparticles encaged inside thermoresponsive PNIPAM Microcapsules

We present a new approach for the fabrication of thermoresponsive polymer microcapsules with mobile magnetic cores that undergo a volume phase-transition upon changing the temperature and are collected under an external magnetic field. We have prepared organic/inorganic composite microspheres with a well-defined core-shell structure that are composed of a crosslinked poly(N-isopropylacrylamide) (PNIPAM) shell and silica cores dotted centrally by magnetite nanoparticles. Since the infiltration of template-decomposed products is dependent on the permeability of PNIPAM shells triggered by changes of exterior temperature, the silica layer sandwiched between the magnetic core and the PNIPAM shell was quantitatively removed to generate PNIPAM microcapsules with mobile magnetic cores by treatment with aqueous NaOH solution. For development of the desired multifunctional microcapsules, modification of the unetched silica surface interiors can be realized by treatment with a silane coupling agent containing functional groups that can easily bind to catalysts, enzymes, or labeling molecules. Herein, fluorescein isothiocyanate (FITC), which is a common organic dye, is attached to the insides of the mobile magnetic cores to give PNIPAM microcapsules with FITC-labeled magnetic cores. In this system, it can be expected that an extension of the functionalization of the cavity properties of smart polymer microcapsules is to immobilize other target molecules onto the mobile cores in order to introduce other desired functions in the hollow cage.     

新型室温酯化法制备纳米SiO2引发剂和原位引发聚合

提出了一种在室温、潮湿和大气环境等温和条件下,通过酯化反应在纳米SiO2微球表面接枝偶氮分子,合成纳米SiO2引发剂的新方法.使用这种纳米SiO2引发剂原位引发单体苯乙烯和甲基丙烯酸甲酯进行自由基聚合,在SiO2表面接枝聚苯乙烯或聚甲基丙烯酸甲酯.结果表明:用合成的纳米SiO2引发剂原位引发单体聚合后,在纳米SiO2表...     

A Facile Method to Coat Nanoparticles with Lipid Bilayer Membrane: Hybrid Silica Nanoparticles Disguised as Biomembrane Vesicles by Particle Penetration of Concentrated Lipid Layers

Natural membrane vesicles, including extracellular vesicles and enveloped viruses, participate in various events in vivo. To study and manipulate these events, biomembrane-coated nanoparticles inspired by natural membrane vesicles are developed. Herein, an efficient method is presented to prepare organic–inorganic hybrid materials in high yields that can accommodate various lipid compositions and particle sizes. To demonstrate this method, silica nanoparticles are passed through concentrated lipid layers prepared using density gradient centrifugation, followed by purification, to obtain lipid membrane-coated nanoparticles. Various lipids, including neutral, anionic, and cationic lipids, are used to prepare concentrated lipid layers. Single-particle analysis by imaging flow cytometry determines that silica nanoparticles are uniformly coated with a single lipid bilayer. Moreover, cellular uptake of silica nanoparticles is enhanced when covered with a lipid membrane containing cationic lipids. Finally, cell-free protein expression is applied to embed a membrane protein, namely the Spike protein of severe acute respiratory syndrome coronavirus 2, into the coating of the nanoparticles, with the correct orientation. Therefore, this method can be used to develop organic–inorganic hybrid nanomaterials with an inorganic core and a virus-like coating, serving as carriers for targeted delivery of cargos such as proteins, DNA, and drugs.     

Nanocomposites of poly(ε-caprolactone) doped with titanium species

Organic–inorganic hybrid nanocomposites were prepared via in situ sol–gel process. The organic phase is a biodegradable polymer, poly(ε-caprolactone) (PCL), while the tetrabutyl titanate (TBT, Ti(OBu)₄) was used as inorganic precursor. Synthesis parameters like acidity medium and precursor amount were investigated in order to assess their influence on hybrid properties. The obtained nanocomposites were characterised by thermal analysis, spectroscopic techniques, transmission electronic microscopy (TEM) and X-ray diffraction to gather information on the structure of the nanocomposites. Mechanical properties and biodegradability were also evaluated. A reaction mechanism based on Fourier transform infrared spectroscopy and NMR results was proposed using methyl acetate as model compound. TEM micrographs of the nanocomposites show a fine good nanoparticles dispersion. Acidic conditions and 10 wt% of precursor lead to a nanocomposite with higher mechanical properties and biodegradability than PCL.     

Self-assembled lamellar MoS2, SnS2 and SiO2 semiconducting polymer nanocomposites

Lamellar nanocomposites based on semiconducting polymers incorporated into layered inorganic matrices are prepared by the co-assembly of organic and inorganic precursors. Semiconducting polymer-incorporated silica is prepared by introducing the semiconducting polymers into a tetrahydrofuran (THF)/water homogeneous sol solution containing silica precursor species and a surface-active agent. Semiconducting polymer-incorporated MoS(2) and SnS(2) are prepared by Li intercalation into the inorganic compound, exfoliation and restack in the presence of the semiconducting polymer. All lamellar nanocomposite films are organized in domains aligned parallel to the substrate surface plane. The incorporated polymers maintain their semiconducting properties, as evident from their optical absorption and photoluminescence spectra. The optoelectronic properties of the nanocomposites depend on the properties of both the inorganic host and the incorporated guest polymer as demonstrated by integrating the nanocomposite films into light-emitting diodes. Devices based on polymer-incorporated silica and polymer-incorporated MoS(2) show no diode behaviour and no light emission due to the insulating and metallic properties of the silica and MoS(2) hosts. In contrast, diode performance and electroluminescence are obtained from devices based on semiconducting polymer-incorporated semiconducting SnS(2), demonstrating that judicious selection of the composite components in combination with the optimization of material synthesis conditions allows new hierarchical structures to be tailored for electronic and optoelectronic applications.     

Synthesis of a thermoresponsive platinum nanocomposite using a three-layer onion-like polymer as template

Using a well-designed three-layer onion-like polymer as template, a one-pot procedure that led to stable, narrow-sized and thermoresponsive Pt nanocomposites is described. The polymer consists of an outer shell of thermoresponsive poly(N-isopropylacrylamide), an inner shell of crosslinked poly(N,N-dimethylaminoethyl acrylate) and a hyperbranched polyglycerol core. The core is physically trapped by the shell, with a few thiol groups located on the interface between the core and the shell. The polymer is used as a template for the synthesis of platinum nanoparticles, ¹H NMR and TEM analyses suggest that the in-situ produced, narrow-sized Pt nanoparticle is loaded in the core part of the polymer so that the nanocomposite retains thermoresponsive activity.     

Poly(3-hexylthiophene)/hexamine modified ZnO hybrid nanocomposite: structural,optical, thermal and electrical transport studies

This paper reports the synthesis of poly(3-hexylthiophene) (P3HT)/HA@ZnO nanocomposite by in situ polymerization and demonstrates their thermal, morphological and optoelectronic properties. Zinc oxide (ZnO) nanoparticles were prepared by the simple approach of co- precipitation method using zinc acetate dihydrate as precursor modified by hexamine (HA) acting as a capping agent. Structural and photo physical studies shows that conjugated polymer chains intimately contact with the inorganic semiconductor. ZnO has wurtzite structure with average crystallite size of 40 nm. The emission spectra indicate that modified ZnO nanoparticles results in more efficient photo induced charge transfer than that of the simple nanocomposite of P3HT/ZnO. The morphological studies revealed that the transformation of granular morphology of P3HT to the clusters in P3HT/HA@ZnO hybrid nanocomposites. Cyclic voltammeter elucidates the electrochemical behavior and the HOMO–LUMO energy levels of the nanocomposites. The results indicate that the P3HT/HA@ZnO nanocomposite has energy gap of 0.72 eV, indicating this composite has potential for the fabricating hybrid organic–inorganic solid state solar cells. A solar to electric energy conversion efficiency of 0.1238 % was attained with the system.     

Multi-walled carbon nanotubes-supported Fe(naph)3 nanoparticles to prepare polyacetylene/multi-walled carbon nanotubes nanocomposites

Carbon nanotubes (CNTs) are a promising candidate for preparing conductive polymer/CNT nanocomposites. CNTs are also an alternative to conventional catalyst support. This report studies multi-walled carbon nanotubes (MWNTs) supported-Fe(naph)₃ nanoparticles to prepare polyacetylene (PA)/MWNT nanocomposites with core–shell structure. The XPS spectra and HRTEM images demonstrate the Fe(naph)₃ nanoparticles successfully deposited on the walls of MWNTs and partially transformed to γ-Fe₂O₃ nanoparticles after heated at 100 °C for 2 h. XRD analysis indicates the formation of PA on the walls of MWNTs. Structural analysis using HRTEM shows that PA/MWNT nanocomposites exhibit core–shell structure. TGA data reveals the stability of PA grown on the exterior walls of MWNTs has been improved. The growth mechanism of PA/MWNT nanocomposites can be explained by a heterogeneous process. The conductivity of the nanocomposites was studied by a four-probe approach and a relatively high conductivity was observed.     

Water-repellent cellulose fiber networks with multifunctional properties

We demonstrate a simple but highly efficient technique to introduce multifunctional properties to cellulose fiber networks by wetting them with ethyl-cyanoacrylate monomer solutions containing various suspended organic submicrometer particles or inorganic nanoparticles. Solutions can be applied on cellulosic surfaces by simple solution casting techniques or by dip coating, both being suitable for large area applications. Immediately after solvent evaporation, ethyl-cyanoacrylate starts cross-linking around cellulose fibers under ambient conditions because of naturally occurring surface hydroxyl groups and adsorbed moisture, encapsulating them with a hydrophobic polymer shell. Furthermore, by dispersing various functional particles in the monomer solutions, hydrophobic ethyl-cyanoacrylate nanocomposites with desired functionalities can be formed around the cellulose fibers. To exhibit the versatility of the method, cellulose sheets were functionalized with different ethyl-cyanoacrylate nanocomposite shells comprising submicrometer wax or polytetrafluoroethylene particles for superhydophobicity, MnFe(2)O(4) nanoparticles for magnetic activity, CdSe/ZnS quantum dots for light emission, and silver nanoparticles for antimicrobial activity. Morphological and functional properties of each system have been studied by scanning and transmission electron microscopy, detailed contact angle measurements, light emission spectra and E. coli bacterial growth measurements. A plethora of potential applications can be envisioned for this technique, such as food and industrial packaging, document protection, catalytic cellulosic membranes, textronic (electrofunctional textiles), electromagnetic devices, authentication of valuable documents, and antimicrobial wound healing products to name a few.