Nanostructured Organic Inorganic Hybrid Material Research Articles

Development and Performance Evaluation of Eco-Friendly POSS-Containing MQL Oil Coolant for Drilling Processes

Drilling work on Inconel, a well-known super-heat-resistant alloy, requires a significant quantity of cutting oil to prevent heat-induced abrasion and damage to the cutting tool, caused by the strength and toughness of the alloy. This high requirement of cutting oil, however, negatively affects the processing environment; therefore, minimum-quantity lubrication (MQL), an eco-friendly cutting-oil-supply method, is attracting attention. The conventional MQL method, however, has the disadvantage that an oil-mist is produced along with high-pressure air; hence, the mist is scattered in the air, making the application of the oil to the cutting point inefficient and rendering the cooling effect to be less than that in wet processing. In this study, therefore, an eco-friendly compound, polyhedral oligomeric silsesquioxane (POSS)—a nanostructured organic–inorganic hybrid material that exhibits better adhesion to materials than conventional MQL-specific oil and is resistant to the heat generated during drilling—was developed by adding POSS to the conventional MQL-specific oil, and the effects were verified.

Cold-Cured Epoxy-Based Organic⁻Inorganic Hybrid Resins Containing Deep Eutectic Solvents.

The development of improved cold-cured resins, to be used as either adhesives or matrices for FRP (fiber reinforced polymer) composites employed in the construction industry, has become the focus of several academic and industrial research projects. It is expected that the use of nano-structured organic–inorganic hybrid materials could represent a realistic alternative to commercial epoxy-based resins due to their superior properties, especially in terms of higher durability against: moisture, temperatures, harsh environments, and fire. In this context, organic–inorganic epoxy hybrids were synthesized by a modified sol–gel method without the addition of water. The experimental formulations were prepared starting from a mixture of a silane-functionalized epoxy resin, alkoxysilane components and a deep eutectic solvent (DES) based on a blend of choline chloride and urea. The latter was added in two different loads in order to analyze in depth its effect as a promoter for an effective dispersion of silica nano-phases, formed through hydrolysis and condensation reactions, into the cross-linked epoxy network. The produced formulations were cold-cured for different time spans in the presence of two hardeners, both suitable for a curing process at ambient temperature. In this first part of a wider experimental program, several analyses were carried out on the liquid (rheological and calorimetric) and cold-cured (calorimetric, thermogravimetric, dynamic-mechanical, flexural mechanical, and morphological) systems to evaluate and quantify the improvement in properties brought about by the presence of two different phases (organic and inorganic) in the same epoxy-based hybrid system.

Controlled release of organic-inorganic nanohybrid:cefadroxil intercalated Zn-Al-layered double hydroxide.

BackgroundThe intercalation of an antibiotic drug, cefadroxil (CD), into the inter-gallery of Zn, Al nitrate-layered double hydroxide (LDH) was accomplished using a co-precipitation method. This formed a nanostructured organic–inorganic hybrid material that can be exploited for the preparation of a controlled release formulation.Materials and methodsThe drug–LDH nanohybrid was characterized by using field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR) thermogravimetric (TG) analysis, X-ray powder diffraction (XRD) and UV–visible (UV–vis) absorption spectroscopy, which confirmed the intercalation process. Release tests of nanohybrid in the presence or absence of NaCl or poly-acrylamide (PAM) were performed in vitro in gastric (pH 1.2), lysosomal (pH 4.0), intestinal (pH 6.8) and blood (pH 7.4) simulated fluid using UV–vis spectroscopy.ResultsAt pH 1.2, LDH was dissolved and intercalated antibiotic released from ZnAl-CD in a molecular form, which led to a significant increase in the antibiotic’s solubility. Results showed that the release of drug from nanohybrid at pH 4.0, 6.8 and 7.4 was a sustained process.ConclusionThis material might reduce side effects by the release of the drug in a controlled manner. However, it was found that the presence of Cl or PAM species in the release media has a negative impact on the release behavior. The weathering mechanism is responsible for the release of CD from the nanocomposite at pH 1.2, while the mechanism of anion exchange may be responsible for the release behavior at pH 4.0, 6.8 and 7.4. A number of kinetic models were chosen to gain more insights into the mechanisms of drug release. At pH 1.2, the zero-order model most satisfactorily explained the release kinetics of CD, while the release data of CD at pH 4.0, 6.8 and 7.4 were governed by Bhaskar kinetics.

Controlled Construction of Nanostructured Organic–Inorganic Hybrid Material Induced by Nanocellulose

Sticky rice lime mortar (SRLM) is a widely used lime-based gelled material in ancient China. Sticky rice plays an important role in the formation of organic–inorganic hybrid material. Inspired by this, a nanostructured organic–inorganic hybrid material (NOHM) was constructed based on the regulation of nanocellulose (NCC) on the crystallization of calcium carbonate. The used NCC was prepared by a green way via simultaneous ball milling and phosphotungstic acid catalyzed hydrolysis. The characteristics of the prepared NOHM were explored to gain insight into the interaction of NCC and mineral during the mineralization of calcium carbonate. The results indicate that nanocellulose plays a crucial role in the formation of nanostructured organic–inorganic hybrid material, which not only induces and regulates the mineralization process of calcium carbonate crystals but also affects the morphology and size of the formed calcium carbonate crystals. The mechanical strength and durability of NOHM were significantly i...

Twin Polymerization--a New Principle for Hybrid Material Synthesis.

Twin polymerization is a novel modular approach for the synthesis of hybrid materials. Using this strategy two distinct polymers of either inorganic or organic nature are produced from a single source monomer in a mechanistically coupled process. Twin polymerization is an elegant way for producing nanostructured organic-inorganic hybrid materials of composition and morphology on demand. The main objective of this Review is the explanation of the principle of various twin polymerization processes and their appropriate terminologies. Different types of twin polymerization are classified with respect to the underlying processes as described in individual examples, demonstrating its potential in material synthesis. Prospects of the synthetic methodology of twin polymerization are demonstrated for different molecular structures of twin monomers and the resulting hybrid materials. A comparison with other scenarios for the synthesis of two different polymers within one procedure is included.

Nonaqueous Synthesis of a Bismuth Vanadate Photocatalyst By Using Microwave Heating: Photooxidation versus Photosensitized Decomposition in Visible‐Light‐Driven Photocatalysis

AbstractA new synthetic route to monoclinic bismuth vanadate using a concept adapted from a nonaqueous synthesis strategy for nanostructured organic–inorganic hybrid materials and metal oxides, introduced recently as twin polymerization, is reported. Microwave‐assisted synthesis starting from bismuth(III) tert‐butoxide and vanadium(V) oxytri(tert‐butoxide) in the presence of 2‐methoxybenzyl alcohol, 2,4‐dimethoxybenzyl alcohol, and 2‐(2‐thienyl)iso‐propyl alcohol gave hybrid materials, which were characterized by solid‐state 13C NMR spectroscopy, CH analysis, atomic absorption spectroscopy, and energy dispersive X‐ray spectroscopy. Subsequent pyrolysis resulted in nanoscale monoclinic bismuth vanadate that showed a high photocatalytic activity. The photocatalytic decomposition of model pollutants such as rhodamine B (RhB), methyl orange, methylene blue, and orange G under visible‐light irradiation using the as‐prepared bismuth vanadate samples was studied with a focus on the influence of the agglomeration behavior. The interplay between the photooxidation of RhB, induced by the excitation of the catalyst using visible light, and the photosensitized decomposition pathway is demonstrated by degradation experiments in solution and the solid state.

A non-aqueous procedure to synthesize amino group bearing nanostructured organic-inorganic hybrid materials.

Amino-functionalized organic-inorganic hybrid materials with a narrow distributed nanostructure of 2-4 nm in size were obtained by means of a template-free and non-aqueous procedure. Simultaneous twin polymerization of novel amino group containing twin monomers with 2,2'-spirobi[4H-1,3,2-benzodioxasiline] has been applied for this purpose. The amino groups of the organic-inorganic hybrid material are useful for post derivatization.

On the interpretation of the Raman spectra of Maya Blue: a review on the literature data

AbstractThe Raman spectroscopy of Maya Blue (MB), a nanostructured organic–inorganic hybrid material, has received considerable attention. A re‐evaluation of the Raman literature data for indigo dye, genuine MB samples and model specimens obtained by the binding of indigo to phyllosilicate clays, such as palygorskite and sepiolite, using chemometric analysis of normalised spectra is reported. Available data present features in support of the following ideas: (1) dehydroindigo accompanies indigo in MB; (2) different topological isomers, i.e. dye molecules attached to different coordinative sites of the palygorskite framework, are involved in MB; and (3) different procedures were probably used for preparing MB in ancient Mesoamerican civilisations. Copyright © 2010 John Wiley & Sons, Ltd.

New nanostructured electrochemical biosensors based on three-dimensional (3-mercaptopropyl)-trimethoxysilane network

The design and characterization of a new nanostructured organic-inorganic hybrid material and its application to L-lactic acid determination are described. This material is based on the integration of the enzyme lactate oxidase (LOx) and gold nanoparticles (AuNPs) into a sol-gel 3D polymeric network derived from (3-mercaptopropyl)-trimethoxysilane (MPTS) previously formed onto a gold surface. MPTS presents the advantage of forming a 3D polymeric network containing a large number of thiol tail groups distributed throughout its structure that enable both its anchoring onto gold surfaces and the AuNPs incorporation. Moreover, this matrix provides a biocompatible environment that preserves the catalytic activity of LOx after its immobilization and allows the incorporation of a high amount of enzyme, which is expected to improve the sensitivity of the final biosensing device. Characterization of the designed biosensing platform was performed using quartz crystal microbalance (QCM), scanning electron microscopy (SEM) and atomic force microscopy (AFM) techniques. From the conjunction of these techniques, information about (i) the kinetic of LOx adsorption process in real time, (ii) the amount of LOx incorporated into the network, and (iii) the morphological characteristics at the nanometre level of the designed biosensing material was obtained. This information is very useful on the development of successful biosensing devices. Finally, the response of the biosensor to L-lactic acid was evaluated. The biosensor responds linearly to L-lactic acid in the range of 50 µM to 0.25 mM, with a sensitivity of 3.4 µA mM(-1) and a detection limit of 4.0 µM.

Maya Blue as a nanostructured polyfunctional hybrid organic–inorganic material: the need to change paradigms

Maya Blue, an ancient nanostructured organic–inorganic hybrid material resulting from the attachment of indigo, a natural dye, to a phyllosilicate clay, palygorskite, has received considerable attention of late. Despite intensive research, several aspects remain unsolved, in particular the nature of the indigo–palygorskite association. Recent results suggest that the Maya Blue pigment is a complex system in which different topological isomers of various indigoid molecules attached to the palygorskite matrix coexist.

Characterization of Nanostructured Organic-Inorganic Hybrid Materials Using Advanced Solid-State NMR Spectroscopy

AbstractWe demonstrate the applications of several novel techniques in solid-state nuclear magnetic resonance spectroscopy (SSNMR) to the structural studies of mesoporous organic-inorganic hybrid catalytic materials. Most of these latest capabilities of solid-state NMR were made possible by combining fast magic angle spinning (at ≥ 40 kHz) with new multiple RF pulse sequences. Remarkable gains in sensitivity have been achieved in heteronuclear correlation (HETCOR) spectroscopy through the detection of high-λ (1H) rather than low-λ (e.g., 13C, 15N) nuclei. This so-called indirect detection technique can yield through-space 2D 13C-1H HETCOR spectra of surface species under natural abundance within minutes, a result that earlier has been out of reach. The 15N-1H correlation spectra of species bound to a surface can now be acquired, also without isotope enrichment. The first indirectly detected through-bond 2D 13C-1H spectra of solid samples are shown, as well. In the case of 1D and 2D 29Si NMR, the possibility of generating multiple Carr-Purcell-Meiboom-Gill (CPMG) echoes during data acquisition offered time savings by a factor of ten to one hundred. Examples of the studied materials involve mesoporous silica and mixed oxide nanoparticles functionalized with various types of organic groups, where solid-state NMR provides the definitive characterization.

Functionalised pseudo-boehmite nanoparticles as an excellent adsorbent material for anionic dyes

Pseudo-boehmite has been functionalised with L-lysine by refluxing an aqueous solution containing these two reactants overnight. The resulting nanosized (<10 nm) product is insoluble in water and has been characterised by solid-state NMR spectroscopy, powder X-ray diffraction analysis, N2 adsorption–desorption analysis and zeta potential measurements. The affinity of this new nanostructured organic–inorganic hybrid material for anionic dyes has been quantified using UV-vis spectrophotometry and by constructing the adsorption isotherms for Acid Blue 9 (AB9), Acid Yellow 23 (AY23), and Acid Red 37 (AR37). Elemental/micro analyses indicate that one lysine molecule is covalently bonded to every 8 nm2 of the functionalised material giving a composition [(AlOOH)230·(H2O)86·(C6N2O2H15)]. The introduction of the positively charged amino groups resulted in a tremendous increase in dye affinity in contrast to the unfunctionalised material. The adsorption isotherms of the functionalised pseudo-boehmite were fitted to the Langmuir model and yielded equilibrium binding constants (Ka) of 2.6 × 103 M−1 for AB9, 1.5 × 105 M−1 for AY23 and 8.4 × 104 M−1 for AR37. AR37 gave a higher monolayer coverage (Cm) value of 0.13 mmol g−1 than AB9 (0.085 mmol g−1) and AY23 (0.081 mmol g−1). Dye adsorption is correlated with surface coverage of L-lysine and, in the case of AR37, two dye molecules are concluded to be adsorbed per L-lysine while for AY23 a multi-point interaction is proposed to result in a lower dye capacity and a relatively higher affinity of this dye for FPB when compared with AR37.

Exceptional Affinity of Nanostructured Organic–Inorganic Hybrid Materials towards Dioxygen: Confinement Effect of Copper Complexes

We report the exceptional reactivity towards dioxygen of a nanostructured organic-inorganic hybrid material due to the confinement of copper cyclam within a silica matrix. The key step is the metalation reaction of the ligand, which can occur before or after xerogel formation through the sol-gel process. The incorporation of a Cu(II) center into the material after xerogel formation leads to a bridged Cu(I)/Cu(II) mixed-valence dinuclear species. This complex exhibits a very high affinity towards dioxygen, attributable to auto-organization of the active species in the solid. The remarkable properties of these copper complexes in the silica matrix demonstrate a high cooperative effect for O(2) adsorption; this is induced by close confinement of the two copper ions leading to end-on mu-eta(1):eta(1)-peroxodicopper(II) complexes. The anisotropic packing of the tetraazamacrocycle in a lamellar structure induces an exceptional reactivity of these copper complexes. We show for the first time that the organic-inorganic environment of copper complexes in a silica matrix fully model the protecting role of protein in metalloenzymes. For the first time an oxygenated dicopper(II) complex can be isolated in a stable form at room temperature, and the reduced Cu(2) (I,I) species can be regenerated after several adsorption-desorption cycles. These data also demonstrate that the coordination scheme and reactivity of the copper cyclams within the solid are quite different from that observed in solution.

Hydrophobic induced supramolecular self-organization of tetrahedral units based on van der Waals interactions

Nanostructured hybrid materials were prepared by sol–gel hydrolysis–polycondensation of tetrakis(4-trisisopropoxysilylphenyl)germane PGe and tetrakis(4-trisisopropoxysilylphenyl) tin PSn which present a tetrahedral germanium or tin central atom. Both precursors presented twelve directions for solid formation oriented regularly on the four directions of the tetrahedron. Their organization was evaluated by X-ray diffraction studies (nanometric scale) and birefringence measurements (micrometric scale). It has been shown that the organization of these solids was influenced by the experimental parameters. The intensities of birefringence lay in the same range (1.6 × 10−3 to 2.1 × 10−3) for all the gels XGe and XSn. Regular parallel rectangular chunks were observed in all cases. The orientation of the optical axis was found perpendicular to the edges of the chunks in all cases. The existence of such optical axes regularly oriented towards the edges of the chunks corresponded to an anisotropic organization at the micrometric scale. The results presented here strengthen the fact that the auto-organization observed in nanostructured organic–inorganic hybrid materials occurs during the formation of Si–O–Si bonds, which transforms intermolecular interactions into intramolecular ones corresponding to the weak van der Waals-type interactions existing between the organic units. The role of hydrophilic–hydrophobic interactions is discussed.

Eu3+/block copolymer nanostructured hybrid materials

The synthesis and spectroscopic characterization of a series of nanostructured organic-inorganic hybrid materials based on functional diblock copolymers and Eu3+ salts is reported. The organic block copolymers were prepared by anionic polymerization and contain a block carrying functional groups, able to complex with Eu3+ cations (i.e. ethylene oxide, 2-vinylpyridine, sulfonate or methacrylic acid units) and a "neutral" non-interacting hydrocarbon block as a structure participating component (i.e. polystyrene or poly(tert butylstyrene)). In these materials the diblock is acting as the nanostructured matrix (having lamellar, cylindrical or spherical morphologies) as well as the inorganic cation fixation agent, whereas the Eu3+ component provides the optical response to the hybrids. The novel materials were characterized using infrared and fluorescence spectroscopy.