Organic-inorganic Interaction Research Articles

Polymer-II-VI Nanocrystals Blends: Basic Physics and Device Applications to Lasers and LEDs.

Hybrid thin films that combine organic conjugated molecules and semiconductors nanocrystals (NCs) have been deeply investigated in the previous years, due to their capability to provide an extremely broad tuning of their electronic and optical properties. In this paper we review the main aspects of the basic physics of the organic–inorganic interaction and the actual state of the art of lasers and light emitting diodes based on hybrid active materials.

Formation of Lamellar Mesostructured Crystalline Silica by Self-assembly of CTAB

Controlling organic-inorganic liquid crystal structures to form lamellar mesostructured crystalline silica nanosheets(LCS) was achieved by using the simple cationic surfactant cetyl trimethyl ammonium bromide(CTAB). The organic-inorganic interaction under the condtions of a high surfactant concentration and suitable synthesis temperature played an important role in the construction of mesostructured crystalline silica.

Peptide Controlled Shaping of Biomineralized Tin(II) Oxide into Flower-Like Particles.

The size and morphology of metal oxide particles have a large impact on the physicochemical properties of these materials, e.g., the aspect ratio of particles affects their catalytic activity. Bioinspired synthesis routes give the opportunity to control precisely the structure and aspect ratio of the metal oxide particles by bioorganic molecules, such as peptides. This study focusses on the identification of tin(II) oxide (tin monoxide, SnO) binding peptides, and their effect on the synthesis of crystalline SnO microstructures. The phage display technique was used to identify the 7-mer peptide SnBP01 (LPPWKLK), which shows a high binding affinity towards crystalline SnO. It was found that the derivatives of the SnBP01 peptide, varying in peptide length and thus in their interaction, significantly affect the aspect ratio and the size dimension of mineralized SnO particles, resulting in flower-like morphology. Furthermore, the important role of the N-terminal leucine residue in the peptide for the strong organic–inorganic interaction was revealed by FTIR investigations. This bioinspired approach shows a facile procedure for the detailed investigation of peptide-to-metal oxide interactions, as well as an easy method for the controlled synthesis of tin(II) oxide particles with different morphologies.

Amphiphilic block copolymers directed synthesis of mesoporous nickel-based oxides with bimodal mesopores and nanocrystal-assembled walls

Mesoporous late-transition metal oxides have great potential in applications of energy, catalysis and chemical sensing due to their unique physical and chemical properties. However, their synthesis via the flexible and scalable soft-template method remain a great challenge, due to the weak organic-inorganic interaction between the frequently used surfactants (e.g., Pluronic-type block copolymers) and metal oxide precursors, and the low crystallization temperature of metal oxides. In this study, ordered mesoporous NiO with dual mesopores, high surface area and well-interconnected crystalline porous frameworks have been successfully synthesized via the facile solvent evaporation-induced co-assembly (EICA) method, by using lab-made amphiphilic diblock copolymer polystyrene-b-poly(4-vinylpyridine) (PS-b-P4VP) as both the structure-directing agent (the soft template) and macromolecular chelating agents for nickel species, THF as the solvent, and nickel acetylacetonate (Ni(acac)2) as inorganic precursor. Similarly, by using Ni(acac)2 and Fe(acac)3 as the binary precursors, ordered mesoporous Fe-doped NiO materials can be obtained, which have bimodal mesopores of large mesopores (32.5 nm) and secondary mesopores (4.0–11.5 nm) in the nanocrystal-assembled walls, high specific surface areas (∼74.8 m2/g) and large pore value (∼0.167 cm3/g). The obtained mesoporous Fe-doped NiO based gas sensor showed superior ethanol sensing performances with good sensitivity, high selectivity and fast response-recovery dynamics.

The scientific connotation of oil and gas formations under deep fluids and organic-inorganic interaction

As a relatively stable craton block in the earth system, the petroliferous basin is influenced by the evolution of the earth system from the early development environment of source rocks, hydrocarbon formation, and reservoir dissolution to hydrocarbon accumulation or destruction. As a link between the internal and external factors of the basin, deep fluids run through the whole process of hydrocarbon formation and accumulation through organic-inorganic interaction. The nutrients carried by deep fluids promote the bloom of hydrocarbon-generating organisms and extra addition of carbon and hydrogen source, which are beneficial to the development of high-quality source rock and enhancement of the hydrocarbon generation potential. The energy carried by the deep fluid promotes the early maturation of the source rock and facilitates the hydrocarbon generation by activation and hydrogenation in high-mature hydrocarbon sources. The dissolution alteration of carbonate rocks and clastic reservoirs by CO2-rich deep fluids improves the deep reservoir space, thus extending the oil and gas reservoir space into greater depth. The extraction of deeply retained crude oil by deep supercritical CO2 and the displacement of CH4 in shale have both improved the hydrocarbon fluidity in deep and tight reservoirs. Simultaneously, the energy and material carried by deep fluids (C, H, and catalytic substances) not only induce inorganic CH4 formation by Fischer-Tropsch (F-T) synthesis and “hydrothermal petroleum” generation from organic matter by thermal activity but also cause the hydrothermal alteration of crude oil from organic sources. Therefore, from the perspective of the interaction of the earth’s sphere, deep fluids not only input a significant amount of exogenous C and H into sedimentary basins but also improve the reservoir space for oil and gas, as well as their enrichment and accumulation efficiencies.

Crystal defects induced by chitin and chitinolytic enzymes in the prismatic layer of Pinctada fucata

Biomineralization, in which organisms create biogenic hard tissues, with hardness or flexibility enhanced by organic–inorganic interaction is an interesting and attractive focus for application of biomimetic functional materials. Calcites in the prismatic layer of Pinctada fucata are tougher than abiotic calcites due to small crystal defects. However, the molecular mechanism of the defect formation remains unclear. Here, chitin and two chitinolytic enzymes, chitinase and chitobiase, were identified as organic matrices related to for the formation of small crystal defects in the prismatic layer. Experiments with a chitinase inhibitor in vivo showed chitinase is necessary to form the prismatic layer. Analysis of calcite crystals, which were synthesized in a chitin hydrogel treated with chitinolytic enzymes, by electron microscopy and X-ray diffraction showed that crystal defects became larger as chitin was more degraded. These results suggest that interactions between chitin and calcium carbonate increase as chitin is thinner.

Deterioration process of the hybrid films during wear test — Polyacrylate emulsion modified by silica particles

The hybrid materials are widely used in various fields for excellent performance. However, there are few researches studying their failure process. In order to prepare the hybrid materials with better performance, the failure process needs to be well studied. Two kinds of silica/polyacrylate films are successfully prepared to study the effect of organic-inorganic interaction on performance. The average diameter of silica particles is measured to be around 342 nm by scanning electron microscope (SEM). Wear test demonstrates the hybrid film, which is obtained by grafting polyacrylate onto silica particles, possesses more excellent properties than the one filled directly with silica particles. The stronger interaction between organic and inorganic components leads to a better distribution of inorganic particles within the polymer matrix. In this work, a model is presented to illustrate the deterioration process of the hybrid films, which allows us to further understand the hybrid materials.

Effects of asperities and organic-inorganic interactions on the strength of nacre-mimetic composites

Nacre is a natural organic-inorganic hybrid composite, whose hierarchical structure has a complex influence on its high strength. Many structural features have been discovered, which influence the mechanical properties of nacre, and the authors have a particular interest in the role of the asperities and organic-inorganic interactions. In this study, a composite was prepared which mimics the asperity structure using clay minerals. Organic-inorganic bonding was induced with silane treatment. Both factors increased the yield strength of the composites; however, different deformation behavior was exhibited. It was found that asperities improved the strength of the composite, and that composition influences the stiffness of the composite. The organic-inorganic interaction between the resin and the other components of the composite reduced the deformation of the composite and consequently improved strength.

Insight into the collective vibrational modes driving ultralow thermal conductivity of perovskite solar cells

The past few years have witnessed a rapid evolution of hybrid organic-inorganic perovskite solar cells as an unprecedented photovoltaic technology with both relatively low cost and high-power conversion. The fascinating physical and chemical properties of perovskites are benefited from their unique crystal structures represented by the general chemical formula $AM{X}_{3}$, where the $A$ cations occupy the hollows formed by the $M{X}_{3}$ octahedra and thus balance the charge of the entire network. Despite a vast amount of theoretical and experimental investigations have been dedicated to the structural stability, electrical, and optical properties of hybrid halide perovskite materials in relation to their applications in solar cells, the thermal transport property, another critical parameter to the design and optimization of relevant solar cell modules, receives less attention. In this paper, we evaluate the lattice thermal conductivity of a representative methylammonium lead triiodide perovskite $({\mathrm{CH}}_{3}{\mathrm{NH}}_{3}{\mathrm{PbI}}_{3})$ with direct nonequilibrium ab initio molecular dynamics simulation. Resorting to full first-principles calculations, we illustrate the details of the mysterious vibration of the methylammonium cluster $({\mathrm{CH}}_{3}{\mathrm{NH}}_{3}^{+})$ and present an unambiguous picture of how the organic cluster interacting with the inorganic cage and how the collective motions of the organic cluster drags the thermal transport, which provide fundamental understanding of the ultralow thermal conductivity of ${\mathrm{CH}}_{3}{\mathrm{NH}}_{3}{\mathrm{PbI}}_{3}$. We also reveal the strongly localized phonons associated with the internal motions of the ${\mathrm{CH}}_{3}{\mathrm{NH}}_{3}^{+}$ cluster, which contribute little to the total thermal conductivity. The importance of the ${\mathrm{CH}}_{3}{\mathrm{NH}}_{3}^{+}$ cluster to the structural instability is also discussed in terms of the unconventional dispersion curves by freezing the partial freedoms of the organic cluster. These results provide more quantitative description of organic-inorganic interaction and coupling dynamics from accurate first-principles calculations, which are expected to underpin the development of emerging photovoltaic devices.

Atomic structure of metal-halide perovskites from first principles: The chicken-and-egg paradox of the organic-inorganic interaction

We have studied the prototype hybrid organic-inorganic perovskite CH3NH3PbI3 and its three close relatives, CH3NH3SnI3, CH3NH3PbCl3 and CsPbI3, using relativistic density function theory. The long-range van der Waals (vdW) interactions were incorporated into the Perdew-Burke-Ernzerhof (PBE) exchange-correlation functional using the Tkatchenko-Scheffler pairwise scheme. Our results reveal that hydrogen bonding, which is well described by the PBE functional, plays a decisive role for the structural parameters of these systems, including the position and orientation of the organic cation as well as the deformation of the inorganic framework. The magnitude of the inorganic-framework deformation depends sensitively on the orientation of the organic cation, and directly influences the stability of the hybrid perovskites. Our results suggest that the organic and the inorganic components complement each other: The low symmetry of the organic cation is the origin of the inorganic-framework deformation, which then aids the overall stabilization of the hybrid perovskite structure. This stabilization is indirectly affected by vdW interactions, which lead to smaller unit-cell volumes than in PBE and therefore modulate the interaction between the organic cation and the inorganic framework. The vdW-induced lattice-constant corrections are system dependent and lead to PBE+vdW lattice constants in good agreement with experiment. Further insight is gained by analysing the vdW contributions. In all iodide-based hybrid perovskites the interaction between the organic cation and the iodide anions provides the largest lattice-constant change, followed by iodine-iodine and the organic cation - heavy-metal cation interaction. These corrections follow an almost linear dependence on the lattice constant within the range considered in our study, and are therefore approximately additive.

The Thermodynamics and Kinetics of the Reaction Between Pyrrole and Water

A thermodynamic problem between pyrrole and water was calculated to investigate the possibility of this reaction. Based on the thermodynamic analysis, simulation experiments on the pyrrole-water system were carried out at 400–500°C. Properties of the reaction products were characterized by gas-chromatography and Fourier transform-infrared spectrometry methods. Apparent reaction kinetics between pyrrole and water were tentatively discussed. The results show that thermochemically the organic-inorganic interaction between pyrrole and water possibly occurs above 100°C, and proceeds spontaneously above 300°C to produce furan and ammonia as the main products. The calculated apparent activation energy for the reaction is 146.91 kJ/mol.

Effects of uranium on hydrocarbon generation of hydrocarbon source rocks with type-III kerogen

Organic-inorganic interaction exists universally and is important in the process of mineral resources formation. It is the essential reason why organic oil, gas, coal and inorganic uranium coexist, accumulate, and mineralize in the same sedimentary basins. Hydrocarbon-generating simulation experiment was conducted using low-mature hydrocarbon source rock containing kerogen type III with uranium (UO2CO3 solution) added to study the effects of uranium on the hydrocarbon generation of hydrocarbon source rocks. Experiment results show that uranium can enhance the yield of gas hydrocarbon, promote the total gas output, and increase the total hydrocarbon production (mass or volume). Uranium may lower the hydrocarbon generation threshold temperature and lead to the generation of liquid hydrocarbon in the relative low temperature of hydrocarbon source rock. Uranium can enhance the yield of saturated hydrocarbon, promote the low molecular weight hydrocarbons generating, and in turn increase the content of CH4 and the content of dry gas of the generated hydrocarbons. Uranium is one of the potential inorganic accelerating factors of the immature hydrocarbons.

Thermal, infrared spectroscopy and molecular modeling characterization of bone: An insight in the apatite-collagen type I interaction

An insight into the interaction of collagen type I with apatite in bone tissue was performed by using differential scanning calorimetry, Fourier transform infrared spectroscopy, and molecular modeling. Scanning electron microscopy shows that bone organic content incinerate gradually through the different temperatures studied. We suggest that the amide regions of the type I collagen molecule (mainly C=O groups of the peptide bonds) will be important in the control of the interactions with the apatite from bone. The amide I infrared bands of the collagen type I change when interacting to apatite, what might confirm our assumption. Bone tissue results in a loss of thermal stability compared to the collagen studied apart, as a consequence of the degradation and further combustion of the collagen in contact with the apatite microcrystals in bone. The thermal behavior of bone is very distinctive. Its main typical combustion temperature is at 360°C with a shoulder at 550°C compared to the thermal behavior of collagen, with the mean combustion peak at ca. 500°C. Our studies with molecular mechanics (MM+ force field) showed different interaction energies of the collagen-like molecule and different models of the apatite crystal planes. We used models of the apatite (100) and (001) planes; additional two planes (001) were explored with phosphate-rich and calcium-rich faces; an energetic preference was found in the latter case. We preliminary conclude that the peptide bond of collagen type I is modified when the molecule interacts with the apatite, producing a decrease in the main peak from ca. 500°C in collagen, up to 350°C in bone. The combustion might be related to collagen type I, as the ΔH energies present only small variations between mineralized and non-mineralized samples. The data obtained here give a molecular perspective into the structural properties of bone and the change in collagen properties caused by the interaction with the apatite. Our study can be useful to understand the biological synthesis of minerals as well as the organic-inorganic interaction and the synthesis of apatite implant materials.

Templating Effect of Mesostructured Surfactant–Silica Monolithic Films on the Surface Structural and Mechanical Properties

Mesostructured surfactant-silica monolithic films were prepared using a supramolecular templating method. The effect of the templating in the monolithic films on the interfacial interactions was evaluated and elucidated using the atomic force microscope techniques combined with other surface analyses to produce different surface structures and force curves depending on the surfactants. The transparent and flexible surfactant-silica monolithic films were prepared to exhibit the ordered nanostructures. The monolithic films templated by nonionic triblock copolymers (poly(ethylene oxide (EO))--poly(propylene oxide (PO))--poly(ethylene oxide (EO))) of EO₂₀PO₇₀EO₂₀ (P123) and EO₁₀₆PO₇₀EO₁₀₆ (F127) significantly exhibited flat surfaces and the higher viscoelastic properties which were supported by surface stiffness and adhesive force, whereas the monolithic film by cationic alkylammonium surfactant indicated a rough surface and the plastic deformation property by application of force. This indicated that the higher molecular weight of the EO and PO phases enhanced the phase segregation in the silica surfaces due to the higher solubility differences between both blocks to consolidate the surfactant-silica interfacial interactions. Therefore, the different surface structural and mechanical properties attributed to the interfacial organic-inorganic interaction patterns were successfully clarified.

Synthesis of Nonspherical Banana-Like Mesoporous Silica and their Vertically Deposition Assembly

Nonspherical mesoporous silica with banana-like morphology has been synthesized successfully through organic-inorganic cooperative interaction by adding the small molecules additives. SEM and TEM image revealed that the silica with banana-like morphology possess hexagonal pore channels and packed parallel to the long axis. XRD further confirmed the high ordered two dimensional (2-D) hexagonal (p6m) mesostructure. N2 adsorption-desorption measurement show that they have high BET surface area and large pore size and pore volume. Impressively, through vertical deposition assembly technique, the anisotropic nonspherical banana-like mesoporous silica can be organized into closely-packed monolayer and multilayer film, demonstrating potential application in photonics, electronics and magnetics.

Modification of Hydroxyapatite-gelatin Nanocomposite using Side Group Reaction of Ca2+-RCOO-

In the preparation of a hydroxyapatite [HAp]/gelatin [GEL] nanocomposite, the GEL matrix in aqueous solution of H 3 PO 4 was modified by the introduction of aspartic acid [Asp], asparagine [Asn], and glycine [Gly]. The addition of Asp, Asn and Gly greatly affected the slurry formation of HAp/GEL nanocomposite and the resulting dry body showed variations in toughness with the addition of the different amino acids. The introduction of Asn into HAp/GEL nanocomposite was effective for producing the organic-inorganic interaction between HAp and GEL, and caused the increase of toughness. The formation reaction of the modified HAP/GEL nanocomposites was investigated by using XRD and FT-IR. The organic-organic interaction between the GEL matrix and the additives of Asp, Asn and Gly was confirmed from FT-IR analysis, and the organic-inorganic interaction between HAp nanocrystallites and the modified GEL matrix was also discussed, using FT-IR spectra patterns. Nanocrystallites of HAp were covalently bound with the GEL macromolecules and differently influenced by the modification species of Asp, Asn, and Gly.

Comparative study of hydroxyapatite/gelatin composites reinforced with bio-inert ceramic particles

Recently, nano bio-composites have emerged as an efficient strategy to upgrade the structural and functional properties of synthetic bone grafts. Bioinert ceramics have attracted wide attention because of their biocompatibility. Novel composites of nano-hydroxyapatite/GEL with incorporation of bioinert ceramics like Al2O3, TiO2 and ZrO2 for different composites as a reinforcing phase to increase its mechanical properties was prepared. The nHAp with the size of 10–50nm in diameter and 50–100nm in length was uniformly distributed into GEL matrix to form the composite. It was found that the composite with a high ceramic content has good homogeneity and mechanical strength, which are close to the cancellous bone. An interconnected porous material with porosity of at least 74% was achieved by phase inversion method. The formation reaction of the nHAp/GEL/bioinert ceramic nanocomposite was then investigated via FT-IR, XRD, TG/DTA and SEM. The organic–inorganic interaction between HAp nano crystallites and GEL molecules were confirmed from FT-IR and TG/DTA. The compressive strength of bioinert ceramic reinforced nanocomposites scaffolds could high up to 13.15MPa while those of nHAp/GEL were 4.87MPa. The nano indentation technique was used to find nano hardness and fracture toughness was evaluated by Vickers indentation.

Localization of intracrystalline organic macromolecules in mollusk shells

As a crucial first step for understanding the organic–inorganic interaction in biomineralization of mollscan shells, localization of the intracrystalline organic macromolecules in biogenic calcium carbonate crystals of the nacreous, prismatic ( Pinctada fucata) and foliated ( Cellana toreuma) microstructures were investigated using Fresnel contrast analysis in a transmission electron microscope. Spherular Fresnel contrasts in the crystals correspond to organic substances, which was confirmed by the detection of 1s→π ⁎ (CC) transition peak at 284 eV in electron energy loss spectroscopy. Nano-sized (5–10 nm) spherules in the aragonite tablets constituting the nacreous layer of P. fucata specifically concentrate in the vicinity of the interlamellar membrane between the aragonite tablets. The dominant sizes of the organic macromolecules extracted by dissolving the aragonite tablets in the nacreous layer of P. fucata were estimated using the gel-filtration analysis to be roughly 10 and 4 nm, which dimensionally corresponds to the sizes observed by Fresnel contrast imaging in the tablets. These results will serve for understanding the functions of intracrystalline organic macromolecules in mollusk shells.

Morphological changes in biomimetically synthesized hydroxyapatite and silver nanoparticles for medical applications

A precise control of morphology, which plays a significant role towards the application of materials, can be achieved by studying the effects of macromolecules as nucleation templates for minerals in a biomineralization process. The present investigation aims to understand such effects on medically important materials. Thus, Silver (Ag) and Calcium hydroxyapatite [Ca10(PO4)6(OH)2] were synthesized in both biopolymer (gelatin) and synthetic polymer (PVA) media, with aqueous medium as the control to portray a collage of how the interface between the macromolecule and the mineral controls the final morphology of the materials. It was also observed that the change of morphology of the products does influence their performances in specific applications like antibacterial property of the nanoparticles of silver was found to the best when synthesized in aqueous media. Thus, we consider that the organic–inorganic interaction to be of vital significance in the synthesis of complex shapes and sizes of nanoparticles for important applications.

Modification of Hydroxyapatite/gelatin Nanocomposite with the Addition of Chondroitin Sulfate

In the preparation of hydroxyapatite (HAp)/gelatin (GEL) nanocomposite, GEL matrix was modified by the introduction of chondroitin sulfate (ChS) to obtain a strongly organized composite body. The formation reaction of the HAp/GEL-ChS nanocomposite was then investigated via XRD, DT/TGA, FT-IR, TEM and SEM. The organic-inorganic interaction between HAp nanocrystallites and GEL molecules was confirmed from DT/TGA and FT-IR. According to the DT/TGA results, the exothermal temperature zone between 300 and 550℃ showed an additional peak temperature that indicated the decomposition of the combined organics of the GEL and ChS. From the FT-IR analysis, calcium phosphate (Ca-P) was covalently bound with the GEL macromolecules modified by ChS. From TEM and ED, the matrix of the GEL-ChS molecules was mineralized by HAp nanocrystallites and the dense dried nanocomposite body was confirmed from SEM micrographs.