Organic Inorganic Nanocomposite Materials Research Articles

Second harmonic generation on crystalline organic nanoclusters under extreme nanoconfinement in functionalized silica–benzil composites

We demonstrate a series of organic–inorganic nanocomposite materials combining the mesoporous silica (PS) and benzil (BZL) nanocrystals embedded into its nanochannels (6.0–13.0 nm in diameter) by capillary crystallization. One aims to design novel, efficient nonlinear optical composite materials in which inactive amorphous host PS-matrix provides a tubular scaffold structure, whereas nonlinear optical functionality results from specific properties of the deposited guest BZL-nanocrystals. A considerable contraction of the BZL melt during its crystallization inside the silica nanochannels results in a formation of the texture consisting of (221)- and (003)-oriented BZL nanoclusters (22 nm in length), separated by voids. Specificity of the textural morphology similarly to the spatial confinement significantly influences the nonlinear optical features of composite PS:BZL materials being explored in the second harmonic generation (SHG) experiment. The light polarization anisotropy of the SHG response appears to be considerably reduced at channel diameters larger than 7 nm apparently due to the multiple scattering and depolarization of the light on randomly distributed and crystallographically oriented BZL-nanoclusters. The normalized SHG response decreases nonlinearly by more than one order of magnitude as the channel diameter decreases from 13.0 to 6.0 nm and vanishes when spatial cylindrical confinement approaches the sizes of a few molecular layers suggesting that the embedded BZL clusters indeed are not uniformly crystalline but are characterized by more complex morphology consisting of a disordered SHG-inactive amorphous shell, covering the channel wall, and SHG-active crystalline core. Understanding and controlling of the textural morphology in inorganic–organic nanocrystalline composites as well as its relationships with nonlinear optical properties can lead to the development of novel efficient nonlinear optical materials for the light energy conversion with prospective optoelectronic and photonic applications.

Biomedical Organic-Inorganic Nanocomposite Materials Based on High-Density Polyethylene and Ultra-High-Molecular-Weight Polyethylene and Silver Nanoparticles

Biomedical Organic-Inorganic Nanocomposite Materials Based on High-Density Polyethylene and Ultra-High-Molecular-Weight Polyethylene and Silver Nanoparticles

Poly(styrene‐alt‐maleic anhydride) ionic salt functionalized reduced graphene oxide doped with rare earth ions for anti‐corrosion performance enhancement

AbstractA novel organic–inorganic nanocomposite material of rare earth ions/ poly(styrene‐alt‐maleic anhydride) ionic salt/ reduced graphene oxide (Re3+/SMA‐Is/rGO) was prepared successfully. Poly(styrene‐alt‐maleic anhydride) ionic salt functionalized reduced graphene oxide (SMA‐Is/rGO) was processed with two methods of π–π conjugation and ionization; rare earth ions (Re3+ = La3+, Ce3+ Pr3+) was doped on the surface of rGO by physical mixing. SMA‐Is reduced surface energy and enlarged the interlayer spacing between rGO nanosheets, ensuring that Re3+/SMA‐Is/rGO could form a uniform dispersed phase in the organic coating. The anti‐corrosion performance of the nanocomposite coating was measured by electrochemical techniques in corrosive medium, revealing that introducing the nanocomposite to epoxy matrix exhibited a significant decline of the increase of corrosion potential and corrosion current density. In all samples, La3+/SMA‐Is/rGO had the highest anti‐corrosion performance, and the protection efficiency on mild steel was up to 98.97%.

Fabrication and Antibacterial Properties of Silver/Graphite Oxide/Chitosan and Silver/Reduced Graphene Oxide/Chitosan Nanocomposites

Silver/graphite oxide/chitosan and silver/reduced graphene oxide/chitosan organic–inorganic nanocomposite materials have been synthesized by a precipitation procedure using graphite oxide or reduced graphene oxide acting as stabilizer, silver acetate as Ag0 precursor, sodium hydroxide as reducing medium, and chitosan as covering agent. The synthesized nanomaterials were thoroughly characterized and their antibacterial efficacy investigated in detail, in comparison with chitosan, graphite oxide, reduced graphene oxide, silver/graphite oxide, and silver/reduced graphene oxide, against Gram-positive bacterium Corynebacterium glutamicum and Gram-negative bacterium Escherichia coli strain DH5α, over durations of 8 h and 20 h. The results confirmed that the prepared nanocomposites exhibited broad-spectrum antibacterial activity against the two bacteria. Five μL (2 g/L) of the nanocomposite samples efficiently reduced the number of bacteria from 108 colony-forming units (CFU)/mL to zero. The chitosan layer did not prevent release of Ag from the nanocomposites, demonstrating their potential use as biocidal materials for different applications.

Preparation and Application of Organic-Inorganic Nanocomposite Materials in Stretched Organic Thin Film Transistors.

High-transparency soluble polyimide with COOH and fluorine functional groups and TiO2-SiO2 composite inorganic nanoparticles with high dielectric constants were synthesized in this study. The polyimide and inorganic composite nanoparticles were further applied in the preparation of organic-inorganic hybrid high dielectric materials as the gate dielectric for a stretchable transistor. The optimal ratio of organic and inorganic components in the hybrid films was investigated. In addition, Jeffamine D2000 and polyurethane were added to the gate dielectric to improve the tensile properties of the organic thin film transistor (OTFT) device. PffBT4T-2OD was used as the semiconductor layer material and indium gallium liquid alloy as the upper electrode. Electrical property analysis demonstrated that the mobility could reach 0.242 cm2·V−1·s−1 at an inorganic content of 30 wt.%, and the switching current ratio was 9.04 × 103. After Jeffamine D2000 and polyurethane additives were added, the mobility and switching current could be increased to 0.817 cm2·V−1·s−1 and 4.27 × 105 for Jeffamine D2000 and 0.562 cm2·V−1·s−1 and 2.04 × 105 for polyurethane, respectively. Additives also improved the respective mechanical properties. The stretching test indicated that the addition of polyurethane allowed the OTFT device to be stretched to 50%, and the electrical properties could be maintained after stretching 150 cycles.

A BICHROMOPHORIC ORGANIC-INORGANIC SEMICONDUCTOR NANOCOMPOSITE: DEVICE READY BROAD SPECTRAL RESPONSE LIGHT-HARVESTING MATERIAL WITH ENHANCED PHOTORESPONSE

Herein, an improved light harvesting organic–inorganic nanocomposite material was obtained by coupling a judiciously developed green-orange absorbing bichromophoric organic salt [R6 G][HFl] and UV-blue absorbing TiO2 QDs. The designed bichromophoric salt is synthesized using a biphasic metathesis reaction and the nanocomposite [R6 G][HFl]-TiO2 is then obtained by single phase overnight stirring of the two components in an optimized ratio. The synthesized nanocomposite results in further broadening of absorption spectrum ranging from UV to NIR with the peak approximately matching the solar irradiation spectrum and demonstrate enhanced absorptivity thereby capable of harvesting the major part of the solar emission. The nanocomposite demonstrates a perfect molecular as well as HOMO-LUMO and valence band–conduction band alignment which enables energy transfer from TiO2 to [R6 G][HFl] and charge transfer between duo as evident from steady state and transient photoluminescence studies. White light irradiation of the nanocomposite film exhibits 450 times higher photocurrent than that of the bare TiO2 film. The slow photocurrent decay time of 46 s confirms that a generous amount of photo generated carriers harvest in the composite sample. This unique nanocomposite structure demonstrating spectral broadening along with charge transfer result in extraordinarily improved photocurrent and photoresponse thereby rendering [R6 G][HFl]-TiO2 nanocomposite an excellent potential active material for a solid state TiO2 based Heterojunction Solar Cell (HJSC). Efficiency of this nanocomposite based HJSC was found to be the highest (4.4 %) among the various other layer by layer structured devices thereby presenting a simplified cell fabrication technique by excluding the necessity of usual layer by layer dye deposition on TiO2 followed by their optimization for best efficiency. Thus, this study presents a thoughtfully designed device ready perfect active material for a TiO2 based HJSC exhibiting good competence.

Stimuli-responsive switchable organic-inorganic nanocomposite materials

Abstract Organic-inorganic nanocomposite materials have attracted a great attention since they cover a wide range of properties by combining the contrasting properties and/or creating novel properties. Functional properties of composites could further be manipulated by stimuli such as light, pH, magnetic/electric field, mechanical force, and heat. When the stimuli can control a wide range of materials’ property, it can be applied to a device with an ON-OFF system: a switch. A switchable material should exhibit the property that is noticeably different upon stimulation (i.e. ON and OFF states) with reversible mechanism. Research on switchable materials has been actively carried out to maximize the difference between ON and OFF states by modifying the structure and composition of nanocomposites, and also on stimuli to control the response time. Switchable materials find their applications in various fields such as catalysts, sensors, photodetectors, memory devices, and drug delivery systems. In this review, we discuss the recent advances in the design/synthesis of organic-inorganic nanoscale materials in which their properties can be controlled in response to a specific stimulus. In addition, we introduce various stimuli (furthermore, multi-stimuli), applications of switchable nanocomposites in a wide range of fields, and also challenges with an outlook.

Dielectric dispersion and relaxations in (PVA-PEO)-ZnO polymer nanocomposites

The organic-inorganic nanocomposite materials consisted of poly(vinyl alcohol) (PVA) and poly(ethylene oxide) (PEO) blend matrix (50/50wt%) dispersed with zinc oxide (ZnO) nanoparticles have been prepared by the aqueous solution-cast method. The dielectric dispersion and relaxation processes in these polymer nanocomposite (PNC) films (i.e., (PVA-PEO)-x wt% ZnO; x = 0, 1, 3 or 5) have been investigated over the frequency range from 20Hz to 1MHz by employing the dielectric relaxation spectroscopy (DRS). Influence of ZnO contents on the complex dielectric permittivity, electrical conductivity, electric modulus and impedance properties of these PNC materials has been explored. The dielectric permittivity and the relaxation time values corresponding to polymers cooperative chain segmental motion significantly change with the variation of ZnO contents in the PVA-PEO blend matrix at ambient temperature. The temperature dependent relaxation times and dc conductivity values of (PVA-PEO)-3wt% ZnO film have been investigated which obey the Arrhenius behaviour. The dielectric permittivity of the film as a function of temperature exhibits linear behaviour at radio frequencies and non-linear variation at lower audio frequencies. X-ray diffraction measurements confirm a huge decrease in crystalline phase of the polymer blend matrix on the addition of 1wt% ZnO nanoparticles. These PNC materials have low values of dielectric permittivity and electrical conductivity which confirm their suitability as novel flexible-type polymer nanodielectric for the insulation in microelectronic devices, whereas the fast chain segmental dynamics and high amorphous phase reveal these materials as a potential candidate for the preparation of nanocomposite solid polymer electrolytes.

Preparation and Characterization of An Aromatic Imide-Functionalized Polysilsesquioxane via the Sol-Gel Route

Phthalic acid (benzene-1,2-dicarboxylic acid, PA) and trimesic acid (benzene-1,3,5-tricarboxylic acid, TA) have been reacted with 3-aminopropyltriethoxysilane (APTES) at 110 °C and 220 °C (molar ratios 1:1 and 1:2). The reaction at 110 °C resulted in the formation of the corresponding poly(amic acid), whereas the thermal imidization at 220 °C gives rise to the formation of a cyclic polyimide moiety as shown by means of Fourier transform infrared spectroscopy (FT-IR). X-ray powder diffraction (XRPD) measurements revealed that a specific periodic arrangement in the as-prepared materials had been formed. Thermogravimetric analysis (TGA) made evident that the organic-inorganic nanocomposite materials showed improved thermal properties. The reaction of PA with APTES (1:1) at 220 °C is assumed to yield a ladder-like polysilsesquioxane.

Sol–gel hybrid materials for aerospace applications: Chemical characterization and comparative investigation of the magnetic properties

In the material science field, weightless conditions can be successfully used to understand the relationship between manufacturing process, structure and properties of the obtained materials. Aerogels with controlled microstructure could be obtained by sol–gel methods in microgravity environment, simulated using magnetic levitation if they are diamagnetic. In the present work, a sol–gel route was used to synthesize class I, organic–inorganic nanocomposite materials. Two different formulations were prepared: the former consisted in a SiO2 matrix in which different percentages of polyethylene glycol (PEG) were incorporated, the latter was a ZrO2 matrix entrapping different amounts of poly (ε-caprolactone) (PCL). Fourier Transform Infrared Spectroscopy (FT-IR) detected that the organic and the inorganic components in both the formulation interact by means of hydrogen bonds. X-ray diffraction (XRD) analysis highlighted the amorphous nature of the synthesized materials and Scanning Electron Microscope (SEM) showed that they have homogeneous morphology and are nanocomposites.Superconducting Quantum Interference Device (SQUID) magnetometry confirmed the expected diamagnetic character of those hybrid systems. The obtained results were compared to those achieved in previous studies regarding the influence of the polymer amount on the magnetic properties of SiO2/PCL and ZiO2/PEG hybrids, in order to understand how the diamagnetic susceptibility is influenced by variation of both the inorganic matrix and organic component.

Characterization and biological properties of TiO2/PCL hybrid layers prepared via sol–gel dip coating for surface modification of titanium implants

Surface modification of implants to facilitate the integration process of the biomaterials is a strategy which has been attracting increasing attention. In this work, the sol–gel method has been used to synthesize organic–inorganic nanocomposite materials consisting of an inorganic titania matrix in which different percentages of a biocompatible polymer, the poly-ε-caprolactone (PCL), have been incorporated. The synthesized materials, still in sol phase, have been used to dip-coat titanium grade 4 substrates to improve the biological properties of the surface. Fourier transform infrared spectroscopy detected the formation of H-bonds between the CO of PCL chains and the –OH groups of the sol–gel matrix. The morphological analysis of films has been performed via scanning electron microscopy (SEM) and has shown that the PCL addition allows the preparation of crack-free and porous coatings; however, uncoated areas develop if PCL is present in high percentages. Bioactivity properties of the coatings have been investigated by soaking coated substrates in a fluid simulating the human blood plasma and evaluating at a later stage the formation of a hydroxyapatite layer on the surface by means of SEM/EDX (energy dispersive X-ray). Coating biocompatibility has been studied by WST-8 assay using 3T3 cells seeded on coated and uncoated substrates.

ZrO2/PEG hybrid nanocomposites synthesized via sol–gel: Characterization and evaluation of the magnetic properties

A sol–gel process was used to synthesize class I organic–inorganic nanocomposite materials consisting of an inorganic ZrO2 matrix in which different percentages of polyethylene glycol (PEG) were incorporated. The formation of hydrogen bonds among the organic and inorganic components was proved by means of Fourier Transform Infrared Spectroscopy (FT-IR) analysis and confirmed by solid-state Nuclear Magnetic Resonance (NMR). X-ray diffraction (XRD) analysis highlighted the amorphous nature of the synthesized materials. Scanning Electron Microscope (SEM) equipped with Back-Scattered Electron Detector (BSED) and Energy Dispersive X-ray (EDX) analysis showed that these materials have homogeneous morphology and nanostructured nature.Superconducting Quantum Interference Device (SQUID) magnetometry confirmed the expected diamagnetic character of these compounds. The measured diamagnetic susceptibility values, which increase with PEG amount and are independent from temperature, make these hybrid materials potentially suitable to be synthesized in magnetic levitation under microgravity conditions.

Structure and magnetic properties of SiO2/PCL novel sol–gel organic–inorganic hybrid materials

Abstract Organic–inorganic nanocomposite materials have been synthesized via sol–gel. They consist of an inorganic SiO 2 matrix, in which different percentages of poly(e-caprolactone) (PCL) have been incorporated. The formation of H-bonds among the carbonyl groups of the polymer chains and Si–OH group of the inorganic matrix has been proved by means of Fourier transform infrared spectroscopy (FT-IR) analysis and has been confirmed by solid-state nuclear magnetic resonance (NMR). X-Ray diffraction (XRD) analysis highlighted the amorphous nature of the synthesized materials. Scanning electron microscope (SEM) micrograph and atomic force microscope (AFM) topography showed their homogeneous morphology and nanostructure nature. Considering the opportunity to synthesize these hybrid materials under microgravity conditions by means of magnetic levitation, superconducting quantum interference device (SQUID) magnetometry has been used to quantify their magnetic susceptibility. This measure has shown that the SiO 2 /PCL hybrid materials are diamagnetic and that their diamagnetic susceptibility is independent of temperature and increases with the PCL amount.

Tailored hybrid hyperbranched polyglycidol-silica nanocomposites with high third-order nonlinearity

Abstract One of the most convenient techniques for optical material fabrication is the sol–gel processing. It can be performed at low temperature that enables one to entrap even relatively unstable organic substances into silica matrix at the nanometer scale, thus developing homogeneous hybrid organic–inorganic nanocomposite materials of various functionalities. Here, novel hybrid organic–inorganic nanocomposites with good optical transparency and high third-order nonlinearity were prepared biomimetically through the mineralization of dendritic macromolecules (hyperbranched polyglycidols) using a compatible ethylene glycol-containing silica precursor. The synthesis was performed at neutral pH media in aqueous solutions without addition of organic solvents at ambient conditions owing to the catalysis of processing. Polyglycidols provided also the formation of gold nanoparticles localized in their core. They served as reducing and stabilizing agents. It is shown that trace amounts of nanoparticles could regulate nonlinear properties of a nanocomposite. High nonlinearity manifests itself in a supercontinuum generation at remarkably short lengths ca. 1 mm. The phenomenon consists of filamentous intense white lighting due to the spectral broadening of initial ultrashort (femtosecond) laser pulses propagating through the material. The developed hybrid nanocomposites possessing large nonlinearity, high-speed optical response, stability under intense lighting, low-cost, and easy preparation are promising for a diverse range of applications as active components for all-optical signal processing from chemical sensing to biological cell imaging and lighting control in telecommunication.

Magnetic Properties and Dielectrical Relaxation Dynamics in CoFe2O4@PU Nanocomposites

Organic–inorganic nanocomposite materials combine the advantages of organic polymers and inorganic nanoparticles. Due to their high application potential, the investigation of these materials is of great interest. In this study we examine the dielectric response of CoFe2O4@PU nanocomposites subjected to an external electric field. Dielectric properties were investigated in a frequency range of 10–2 Hz to 1 MHz and over a temperature range of 213 to 333 K, while varying the content of ferromagnetic particles. The experimental results provide insight to the structure–property relationship of nanocomposites subjected to an alternating electric field. We discuss two relaxation processes (β- and α-processes) that show a dependence on the particle content. For the β-process we observe an Arrhenius-like behavior with temperature, and the related activation energies decrease with increasing particle content. Evidently, the particles' presence facilitates the β-process relaxation in the polymer matrix, resulting i...

Synthesis of hybrid organic–inorganic nanocomposite materials based on CdS nanocrystals for energy conversion applications

Efficient solar energy conversion is strongly related to the development of new materials with enhanced functional properties. In this context, a wide variety of inorganic, organic, or hybrid nanostructured materials have been investigated. In particular, in hybrid organic–inorganic nanocomposites are combined the convenient properties of organic polymers, such as easy manipulation and mechanical flexibility, and the unique size-dependent properties of nanocrystals (NCs). However, applications of hybrid nanocomposites in photovoltaic devices require a homogeneous and highly dense dispersion of NCs in polymer in order to guarantee not only an efficient charge separation, but also an efficient transport of the carriers to the electrodes without recombination. In previous works, we demonstrated that cadmium thiolate complexes are suitable precursors for the in situ synthesis of nanocrystalline CdS. Here, we show that the soluble [Cd(SBz)2]2·(1-methyl imidazole) complex can be efficiently annealed in a conjugated polymer obtaining a nanocomposite with a regular and compact network of NCs. The proposed synthetic strategies require annealing temperatures well below 200 °C and short time for the thermal treatment, i.e., less than 30 min. We also show that the same complex can be used to synthesize CdS NCs in mesoporous TiO2. The adsorption of cadmium thiolate molecule in TiO2 matrix can be obtained by using chemical bath deposition technique and subsequent thermal annealing. The use of NCs, quantum dots, as sensitizers of TiO2 matrices represents a very promising alternative to common dye-sensitized solar cells and an interesting solution for heterogeneous photocatalysis.

Chitosan/NiO nanocomposites: a potential new dielectric material

The study of electrochemical behavior of organic–inorganic nanocomposite materials remains a major challenge for application in energy storage devices. Here, new composite materials of chitosan and NiO nanoparticles have been fabricated. The NiO nanoparticles are well characterized by infrared spectroscopy, X-ray diffraction and transmission electron microscopy. The electrical properties of the films are studied by impedance spectroscopy at different temperatures; and thereby permittivity, electric modulus and conductivity data are obtained. By studying the variations in permittivity and electric modulus spectra with respect to applied frequency signal and temperature, the ionic conductivity of the material is investigated. The Correlated Barrier Hopping model is employed to understand the conduction mechanism. An admirable conductivity of 1.4 × 10−2 S cm−1 is obtained for a nanocomposite with 4 wt% NiO content. The activation energies of the composite films decrease with increase in NiO content, from 16.5 to 4.8 kJ mol−1.

Synthesis and application of solar cells of poly (3-decylthiophene)/N/titanium dioxide hybrid

An organic-inorganic nanocomposite material of poly (3-decylthiophene) and titanium dioxide doped with N (P3DT/N/TiO2) were synthesized. Structures were characterized using X-ray diffraction (XRD), infrared spectroscopy (IR), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). Optical and electrochemical properties were determined using UV-visible spectroscopy, fluorescence spectroscopy, and cyclic voltammetry. These tests indicated that P3DT/N/TiO2 was a new p-n semiconductor photoelectric material, and the solar cell prepared with P3DT/N/TiO2 performed well.

Transparent solar cell window module

A transparent solar cell window module based on the integration of traditional silicon solar cells and organic–inorganic nanocomposite material was designed and fabricated. The transparent solar cell window module was composed of a nanocomposite light-guide plate and traditional silicon solar cells. The preparation of the nanocomposite light-guide plate is easy without modification of the traditional casting process, the nanoparticles sol can be added directly to the polymethyl methacrylate (PMMA) monomer syrup during the process. The solar energy collected by this window can be used to power up small household electrical appliances.

Comparative studies on adsorption behavior of thionine on gold nanoparticles with different sizes

The adsorption behavior of thionine on gold nanoparticles of two different mean diameters, 18 and 5 nm, was compared by using UV–vis spectroscopy, fluorescence spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, transmission electron microscopy (TEM), dynamic light scattering (DLS), and quantum chemical calculations. It is found that the addition of small particles makes the monomer peak of thionine finally disappear, and the corresponding dimer peak is significantly increased. Small gold nanoparticles make the equilibrium between the monomer and H-type dimer forms of thionine move largely toward the dimer forms. Due to the stronger binding between thionine and small gold nanoparticles, the fluorescence quenching of thionine by small particles is enhanced compared to large particles, and the quenching is both static and dynamic. TEM images indicate that the addition of thionine results in a heavy clustering for small particles, and the resulting thionine–gold nanoclusters of about 45 nm were obtained. Quantum chemical calculations, which were based on the density functional theory (DFT) at the B3LYP level, and infrared spectroscopic studies show that the nitrogen atoms of the NH 2 moieties of thionine bind to the gold nanoparticle surfaces. For 18 and 5 nm particles, the surface-to-volume atomic ratios are about 0.0597 and 0.2148, respectively. The higher surface-to-volume atomic ratio and the higher surface free energy result in stronger binding of thionine on small particle surfaces, which can be used to modulate the arrangement of dye molecules on particle surfaces, and thus control the properties of organic–inorganic nanocomposite materials.