Organic/Inorganic Nanohybrid Materials

The literature review (94 articles and patents, published in majority in last decade) of methods of synthesis and selected properties of a new group of nano-hybrid polymers, containing chemically incorporated molecules of polyhedral silsesquioxanes (POSS), has been done. The effect of POSS on mechanical and thermal properties as well as on morphology of such polymers was described. Application directions of nano-hybrid materials discussed were also presented.

tNovel anticorrosive emulsion-type paints were prepared by utilizing organic/inorganic nanohybrid par-ticles (nHPs) of composition (1:1) based on polyaniline (PANI) and nanosilica. Polyaniline (PANI) andnanosilica were synthesized via chemical oxidative and sol–gel polymerization techniques respectively.The prepared materials were characterized via (gel permeation chromatography (GPC), infra red (FT-IR), transmission electron microscope (TEM) and differential scanning calorimetry (DSC)). The binderused in this context is polyvinyl acetate (PVAc). Nanohybrid particles/PVAc emulsion composites (nHPsECs) were simply formed by individual mixing of the prepared neat PANI and nHPs of composition (1:1)with PVAc to produce the corresponding nanohybrid particles/PVAc emulsion composites EC1and EC2respectively. The chemical and basic properties including (acid and alkali resistance, adhesion, washabil-ity, gloss, opacity, whiteness, hardness, impact, and weathering) as well as the anticorrosion propertiesof the blank paint films and the paint films containing neat PANI and nHPs of different concentrations(5%, 10%, and 15%) were investigated and evaluated. The obtained experimental results revealed that thepresence of nHPs in the blank paint are highly enhanced both basic and anticorrosion properties of thecoated films.

This paper is a review of the most recent and
relevant achievements (from 2001 to 2013) on the development
of organic–inorganic hybrid (OIH) coatings produced
by sol–gel-derivedmethods to improve resistance to
oxidation/corrosion of different metallic substrates and
their alloys. This review is focused on the research ofOIH
coatings based on siloxanes using the sol–gel process
conducted at an academic level and aims to summarize the
materials developed and identify perspectives for further
research. The fundamentals of sol–gel are described,
including OIH classification, the interaction with the
substrate, their advantages, and limitations. The main
precursors used in the synthesis ofOIHsol–gel coatings for
corrosion protection are also discussed, according to the
metallic substrate used. Finally, a multilayer system to
improve the resistance to corrosion is proposed, based on
OIH coatings produced by the sol–gel process, and the
future research challenges are debated.

Polyhedral oligosilsesquioxane (POSS)-based hybrid polymers have generated much interest recently, both from the academic and industrial points of view. POSS are completely defined molecules of nanoscale dimensions that may be functionalized with reactive groups suitable for the synthesis of new organic–inorganic hybrids, thus providing the opportunity to design and build materials with extremely well-defined dimensions possessing nanophase behavior. POSS have been successfully incorporated into common polymers via copolymerization, grafting or blending. A variety of POSS-containing copolymers have been prepared and they have displayed great potential in the development of a wide range of hybrid nanomaterials with diverse properties. This work has critically evaluated the recent developments in syntheses of POSS polymer materials leading to POSS nanocomposites. The syntheses of POSS cages, monomers containing POSS cages, POSS-dendrimers' cores, POSS-containing polymers (nanobuilding blocks) and POSS nanocomposites are described in detail. This work also assesses the properties of POSS nanobuilding blocks that can be otherwise used for developing nanocomposites. Such properties include mechanical, thermal, flame-retardant and viscoelastic properties. Investigations into the structure, morphology and compatibility of POSS nanobuilding blocks have been reviewed. Other properties covered include the ion-mobility and swelling characteristics as well as porosity of POSS nanobuilding blocks. Lastly, existing and possible future applications are highlighted and final conclusions are drawn.

Schottky barrier diodes based on a composite of polyaniline with titanium oxide (TiO2) were
fabricated using aluminum as a Schottky contact and gold as an ohmic contact. The observed currentvoltage
characteristics can be satisfactorily fitted using the modified Schottky equation. The current-voltage
characteristics were studied to explain the rectification generation of the diode. The diode shows non-ideal
I-V behavior with an ideality factor greater than unity. The conduction mechanism was determined and a
Schottky-type conduction process was defined. The diode parameters such as saturation current density
and ideality factor were found to be 9.28 × 10−4 A/cm2 and 6.33, respectively.

A series of hybrid polyurethane–POSS materials have been synthesized on the basis of poly(tetramethylene glycol) (Terathane 1400®) as soft component, 4,4′-methylenebis(phenylisocyanate) (MDI) as hard component, and 1,4-butanediol as chain extender. POSS particles properly modified have been tethered on the main chain by substitution of the chain extender to weight fractions up to 10%. AFM measurements indicate the formation of POSS crystallites in the PU matrix, extended structures at low POSS content and more regular, smaller structures at higher POSS content. A detailed investigation of molecular mobility by means of Differential Scanning Calorimetry (DSC), Thermally Stimulated Depolarization Currents (TSDC) and, mainly, Broadband Dielectric Relaxation Spectroscopy (DRS) has been conducted in all samples of the series and in addition in neat Terathane, as reference. Four relaxations have been studied in detail: two secondary relaxations γ and β, the segmental α relaxation (dynamic glass transition) and an α′ relaxation slower than α associated with crystallinity in neat Terathane and with the presence of hard microdomains in the polyurethane and the hybrids. Secondary relaxations remain unaffected by POSS. The glass transition temperature rises by a few degrees and, in consistency with that, segmental dynamics slightly slows down with increasing POSS content. In addition, the dielectric strength of the segmental relaxation decreases with increasing POSS content, suggesting that a fraction of polymer is immobilized, making no contribution to the relaxation. These results are discussed in relation to morphology.

Vertically aligned polyaniline (PANI) nanotubes have great potential application in supercapacitor electrode
material. In this paperwehave investigated facile growth of PANI nanotubes on a titanium nanotube
template (TNT) using electrochemical polymerization. The morphology of PANI nanostructures grown
over TNT is strongly influenced by the scan rate in the electrochemical polymerization. The growth morphology
of PANI nanotubes has been carefully analyzed by field emission scanning electron microscopy.
The detailed growth mechanism of PANI nanotubes has been put forward. Specific capacitance value of
740Fg−1 was obtained for PANI nanotube structures (measured at charge–discharge rate of 3Ag−1).

Nano-layered hybrid compounds composed of a polyfluoroalkyl azobenzene surfactant (abbreviated as C3F-Azo-C6H) and layered inorganic nanosheets undergo three-dimensional morphological changes such as reversible shrinkage and expansion of interlayer spaces, and nanosheet sliding by photo-irradiation. Previously, we have investigated the photoreactivity of C3F-Azo-C6H/clay nano-layered hybrids in various microenvironments and found a remarkable enhancement in the photoreactivity for the cis-trans photo-isomerization reaction (F cis-trans = 1.9). In this paper, nanosecond and microsecond dynamics of trans-C3F-Azo-C6H and its assembly in various microenvironments have been studied by laser flash photolysis to get deeper insight into the extraordinary reactivity of the molecular assembly in the nano-layered microenvironment. In solution, the molecular trans-C3F-Azo-C6H exhibited only a depletion of the transform of azobenzene upon the laser pulse excitation. On the other hand, in the case of the C3F-Azo-C6H/clay hybrid film, the depletion of the transform was drastically recovered in three steps on nano-and microsecond timescales. This indicates that the once reacted C3F-Azo-C6H molecule (cis-C3F-Azo-C6H) was reverted back to the transform after the laser pulse. It is considered that the excess energy provided by the photo-excitation, which is immediately dissipated to the surrounding media through the intermolecular vibrational modes in solution, is trapped in the nano-layered microenvironment to thermally revert the cis-form back to the transform. Conversely, in the case of cis-trans isomerization of the C3F-Azo-C6H/clay hybrid film upon photo-irradiation, the reactivity would be much enhanced by the additional contribution of the thermal excess energy efficiently trapped in the nano-layered microenvironment. As compared with the hydrocarbon analogue (C3H-Azo-C6H), the subsequent recovery was very much enhanced in the C3F-Azo-C6H/clay film. The polyfluoroalkyl part of the surfactant layer plays a key role in the retarded dissipation of the excess energy by photo-excitation, which might be coupled with the three-dimensional morphological motion with efficient isomerization reactions.

Two new polyoxometalate (POM)-based hybrid monomers (Bu 4 N) 5 (H)[P 2 V 3 W 15 O 59 {(OCH 2) 3 CNHCO(CH 3)C=CH 2 }] (2) and (S(CH 3) 2 C 6 H 4 OCOC(CH 3) = CH 2) 6 [PV2Mo 10 O 40 ] (5) were developed by grafting polymerizable organic units covalent-ly or electrostatically onto Wells–Dawson and Keggin-type clusters and were characterized by analytical and spectro-scopic techniques including ESI-MS and/or single-crystal X-ray diffraction analyses. Radical initiated polymerization of 2 and 5 with organic monomers (methacryloyloxy)phenyldi-methylsulfonium triflate (MAPDST) and/or methylmethacry-late (MMA) yielded a new series of POM/polymer hybrids that were characterized by 1 H, 31 P NMR and IR spectroscopic techniques, gel-permeation chromatography as well as thermal analyses. Preliminary tests were conducted on these POM/polymer hybrids to evaluate their properties as photo-resists using electron beam (E-beam)/extreme ultraviolet (EUV) lithographic techniques. It was observed that the POM/polymer hybrid of 2 with MAPDST exhibited improved sensitivity under EUV lithographic conditions in comparison to the MAPDST homopolymer resist possibly due to the efficient photon harvesting by the POM clusters from the EUV source.

A power conversion efficiency of 9.02% is obtained for a fully solution-processed polymer tandem solar cell, based on the diketopyrrolopyrrole unit polymer as a low bandgap photoactive material in the rear subcell, in conjunction with a new robust interconnecting layer. This interconnecting layer is optically transparent, electrically conductive, and physically strong, thus, the charges can be collected and recombined in the interconnecting layer under illumination, while the charge is generated and extracted under dark conditions. This indicates that careful interface engineering of the charge-carrier transport layer is a useful approach to further improve the performance of polymer tandem solar cells. Back in 2011, Mitsubishi Chemical established a 10% efficiency of single junction organic photovoltaic (OPV) 1 Later, Heliatek and Yang and their respective co-workers also announced double digits efficiency for their multiple junctions OPVs 2–4. Since then, we have seen fast progress in OPV, especially in terms of anode or cathode interfa-cial layers, active layers (ternary systems), and in synthesizing low bandgap polymers. The former usually offered some advantages including high short-circuit current density (J SC), as well as complementary absorption of up to 1000 nm. However, it is rather difficult to obtain an excellent low bandgap polymer which can offer both high J SC and also high V OC of > 0.8 V, while providing complementary absorption. Until recently, Mitsubishi Chemical has had great success in single junction PV, where they announced an NREL certified efficiency of 11.1% 5. Such a large jump from 10 to 11.1% must be from an exceptionally high quality polymer or small molecule. In addition, several groups have demonstrated a triple-junction polymer and small molecule PVs exceeding 11% PCE 6–8. Triple-junction PVs in particular have been proposed to make full use of the 1 + 1 + 1 device configuration employing wide, medium, and low bandgap materials as the front, middle, and bottom subcells, respectively 6. However, an excellent donor material is required in order to achieve high performance triple-junction PV. In this research field, chemists usually employ either benzothiadiazole (BT) 9 , diketopyrrolopyrrole (DPP) 10–12 , isodingo 13 , or terthiophene 14 , units as the pillar in designing high quality low bandgap polymers. Recently, Y. Yang and R. A. J. Janssen, with their respective co-workers, were able to produce excellent and good low bandgap polymers, where Yang et al. introduced two strong electron-withdrawing fluorene atoms onto the benzothiadiazole (BT) unit, to form the difluorobenzothiadiazole (DFBT) unit in order to lower the highest occupid molecular orbital (HOMO) 9. On the other hand, Janssen et al. developed a low bandgap polymer with diketopyrrolopyrrole (DPP) as an electron-poor conjugated unit, alternating with a terthiophene unit, which is electron-rich and can absorb well into the NIR region (960 nm) 10 Hence, at this point, it is clear that both the low bandgap polymer and multiple junction OPVs concepts have proven viable. These will most likely be found in future incarnations of OPVs, provided that the appropriate metal electrode can be coated by printing technology. In the present study, we describe a method for preparing inverted tandem solar cells which are compatible with an all printable process. In general, there are a few issues in achieving high performance polymer tandem solar cells which go beyond the processing and optimizing of a single junction OPV 11,12 Primarily, the fabrication of polymer tandem solar cells usually consists of two and sometimes more active materials. It is challenging since these active materials usually are prepared from comparable organic solvents. Thus, to prevent the underneath front subcell from dissolving again during the deposition of a rear subcell, the middle electrode, or the so-called interconnecting layer (ICL), must be processed from an orthogonal solvent, typically some aqueous solution or suspension. Solution processed electron transport materials, namely zinc oxide (ZnO) and titanium dioxide (TiO 2) have been introduced as n-type buffer layer in organic photovoltaic devices 10–12,15,16. Meanwhile, a p-type material poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) has been widely used to transport the hole from active layer to its respective electrode. Nonetheless, our commonly used PEDOT:PSS is not able to give perfect protection. Thus, Yang et al. introduced surfactant and dimethylformamide

Reported here is the synthesis of a series of polyurethane/POSS nanohybrid elastomers, the characterisation of their thermal stability and degradation behaviour at elevated temperatures using a combination of thermogravimetric Analysis (TGA) and thermal volatilisation analysis (TVA). A series of PU elastomer systems have been formulated incorporating varying levels of 1,2-propanediol-heptaisobutyl-POSS (PHIPOSS) as a chain extender unit, replacing butane diol. The bulk thermal stability of the nanohybrid systems has been characterised using TGA. Results indicate that covalent incorporation of POSS into the PU elastomer network increases the non-oxidative thermal stability of the systems. TVA analysis of the thermal degradation of the POSS/PU hybrid elastomers have demonstrated that the hybrid systems are indeed more thermally stable when compared to the unmodified PU matrix; evolving significantly reduced levels of volatile degradation products and exhibiting a ∼30 °C increase in onset degradation temperature. Furthermore, characterisation of the distribution of degradation products from both unmodified and hybrid systems indicate that the inclusion of POSS in the PU network is directly influencing the degradation pathways of both the soft and hard-block components of the elastomers: The POSS/PU hybrid systems show reduced levels of CO, CO2, water and increased levels of THF as products of thermal degradation.

Rectangular shaped GO-CuO nanocomposites have gained special attention because of spectacular applications in wastewater treatment. However, due to a lack of research, the fuel additive properties of GO-CuO are still unreported. A proper synthesis and characterisation methods are necessary to investigate the fuel additive properties of GO-CuO. The present research demonstrates the synthesis of graphene oxide (GO) sheets via modified Hummers' method. Further, GO-CuO nanohybrid was prepared by fast, cost-effective, and easy to handle solvothermal approach. The crystal data such as crystal structure, unit cell parameters, space groups, crystal system, and coordinates were explained via XRD analysis. Physical and combustion properties of fuel were analysed at different concentrations (0, 20, 40, 60, and 80 ppm) of diesel-GO-CuO blend for fuel quality parameters. The flash point and fire point of pure diesel oil were observed as 78 and 80 °C which were decreased to 50 and 58 °C, respectively, at 80 ppm concentration. With GO-CuO nanocomposites, the cloud point and pour point decrease until a temperature of −8 °C and − 19 °C, respectively, with a pronounced decrease in the viscosity up to 1.83 mm2/s. Further, the photocatalytic degradation of Methylene Red (MR) dye is studied with the effect of changing H2O2, photocatalyst, and dye concentrations with time. Remarkably, the reaction kinetics and MR degradation of about 94% with sixth-time recyclability were observed. The results of this study showed improved MR degradation when using GO-CuO with H2O2. GO-CuO applications can be utilised to remove other dyes in future and to improve fuel quality parameters.

Polyhedral Oligomeric Silsesquioxanne particles were tethered by urethane or urea linkages on the hard segments of polyurethane chains with varying segment Mw. Evidence by imaging, thermal and dielectric techniques suggests that tethering of POSS by urethane bond leads to increase of glass transition temperature by a few degrees due to two mechanisms: the direct POSS-chain interactions and the indirect slowing of dynamics by disruption of microphase separation. The direct mechanism is dominant for the materials with long (high Mw) segments and the indirect becomes more important as the Mw of the segments decreases. High polarity of the urea bond counteracts the effect of disruption of microphase separation and enhances an interfacial glass transition mechanism α′, slower than α, leading to significantly higher apparent glass transition temperatures, despite its small effect on time scales of the individual relaxations.

The main goal of this study was to produce a novel porous scaffold for rapid in vivo bone healing behavior. Lyophilization technique was used to produce this highly porous hybrid scaffold from Na-alginate (S) and hydroxyethylcellulose (HEC) impregnated with different concentration of hydroxyapatite (HA). After cross-linking the scaffolds, their incubation was carried out in simulated body fluid (SBF) for 4 weeks at 37 °C to investigate their bioactivity. A number of techniques were employed (e.g., XRD, FTIR, SEM, EDX, and texture analyzer) to characterize the designed scaffolds. It was observed that the mechanical properties of the scaffolds increase deformation energy (182 ± 16 J/m) and rigidity gradient (19.44 ± 0.85 Pa) after loading with HA. Furthermore, the scaffolds were implanted in femur critical size defects (2 mm) of adult male Wistar rats for 6 weeks. In vitro and in vivo analyses demonstrated impressive bioactivity and biocompatibility for the prepared scaffolds, especia...

Hybridized plexcitonic states have unique properties which have been widely studied in recent decades in many research fields targeted at both fundamental science and innovative applications. However, to make these applications come true one needs to ensure the stabilization and preservation of electronic states and optical transitions in hybrid nanostructures, especially under the influence of external stressors, in regimes, that have not yet been comprehensively investigated. The present work shows that the nanohybrid system, composed of plasmonic nanoparticles and J-aggregates of organic molecules, displays outstanding resistance to harsh environmental stressors such as temperature, pH and strong light irradiation as well as demonstrates long-term stability and processability of the nanostructures both in weak and strong coupling regimes. These findings contribute to a deeper understanding of the physicochemical properties of plexcitonic nanoparticles and may find important implications for the development of potential applications in optoelectronics, optical imaging and chemo-bio-sensing and, in general, in the field of optical materials science. † Electronic supplementary information (ESI) available. See

Bragg mirrors (BM) based on TiO x and SiO 2 layers were built on glass and PET substrates at operating wavelength in the visible region. The layers were processed by the sol–gel method at room temperature and dried in air for one hour at 100 °C (glass) and 70 °C (PET). At these deposition conditions, the re-fractive indices of the TiO x and SiO 2 layers were 2 and 1.49, respectively. The BM were assembled in a multilayer stack of quarter-wave thickness of alternately high and low refractive index materials. We report the experimental and simulated optical reflection spectra of TiO x –SiO 2 BM for different number of layers pairs.

Within the density functional theory (DFT) framework, we study the structural properties and the spin density distribution of copper hydroxide acetate Cu2(OH)3(CH3COO)·H2O, a fundamental compound in the field of hybrid organic-inorganic materials. In particular, after a careful comparison of the computed structure with the experimentally obtained X-ray pattern, we provide an insight into the effect of two exchange-correlation functionals (BLYP and HCTH/120) on the description of the magnetic properties and on the related changes in the atomic structure. Since these compounds are known to possess a piezomagnetic character, for the total spin value S = 0 and S = 4, we inspect at different pressures, and for each one of the two exchange-correlation functionals, the changes in the geometry and in the spin density distribution. We notice that, at total spin density S = 0, and for both the external pressures of 3 and 5 GPa, most of the local spin densities are due to dyz orbitals with about 25% contribution from dz2 orbitals. Such a feature is insensitive to the exchange-correlation functional adopted. Overall, our results provide an important first step towards the comprehension of the effects of an external stress on the magnetic properties of this class of hybrid materials.

A chemical structure of polyurethane/functionalized silsesquioxane (PUR/PHIPOSS) nanohybrid materials obtained by prepolymer method has been determined. In the 1H NMR and 13C NMR spectra signals from protons and carbon atoms of the characteristic fragments of the PHIPOSS pendant group have been identified. Analysis of the obtained PUR/PHIPOSS elastomers by ATR-FTIR allowed us to estimate the influence of oligosilsesquioxane side groups on the density of the hydrogen bonds and phase separation. It was found that the degree of phase separation increases with increasing PHIPOSS content.

The main goal of this study was to produce a novel porous scaffold for rapid in vivo bone healing behavior. Lyophilization technique was used to produce this highly porous hybrid scaffold from Na-alginate (S) and hydroxyethylcellulose (HEC) impregnated with different concentration of hydroxyapatite (HA). After cross-linking the scaffolds, their incubation was carried out in simulated body fluid (SBF) for 4 weeks at 37 °C to investigate their bioactivity. A number of techniques were employed (e.g., XRD, FTIR, SEM, EDX, and texture analyzer) to characterize the designed scaffolds. It was observed that the mechanical properties of the scaffolds increase deformation energy (182 ± 16 J/m) and rigidity gradient (19.44 ± 0.85 Pa) after loading with HA. Furthermore, the scaffolds were implanted in femur critical size defects (2 mm) of adult male Wistar rats for 6 weeks. In vitro and in vivo analyses demonstrated impressive bioactivity and biocompatibility for the prepared scaffolds, especia...

The main goal of this study was to produce a novel porous scaffold for rapid in vivo bone healing behavior. Lyophilization technique was used to produce this highly porous hybrid scaffold from Na-alginate (S) and hydroxyethylcellulose (HEC) impregnated with different concentration of hydroxyapatite (HA). After cross-linking the scaffolds, their incubation was carried out in simulated body fluid (SBF) for 4 weeks at 37 °C to investigate their bioactivity. A number of techniques were employed (e.g., XRD, FTIR, SEM, EDX, and texture analyzer) to characterize the designed scaffolds. It was observed that the mechanical properties of the scaffolds increase deformation energy (182 ± 16 J/m) and rigidity gradient (19.44 ± 0.85 Pa) after loading with HA. Furthermore, the scaffolds were implanted in femur critical size defects (2 mm) of adult male Wistar rats for 6 weeks. In vitro and in vivo analyses demonstrated impressive bioactivity and biocompatibility for the prepared scaffolds, especia...

The influence of polyhedral oligomeric silsequioxanes (POSS) as covalently bound hybrid physical property modifiers on the segmental dynamics and morphology of segmented polyurethane elastomers has been studied by solid-state magic sandwich echo nuclear magnetic resonance (MSE-NMR), differential scanning calorimetry (DSC) and atomic force microscopy (AFM). A model system has been synthesized which incorporates diol functionalized POSS over a range of loadings into the hard-block of a methylene di-isocyanate - butane diol - poly(tetramethylene glycol) (MDI-BDO-PTMG) segmented PU elastomer. MSE-NMR has been employed to probe the segmental dynamics of the PU system as a function of POSS loading and it has been demonstrated that low levels of POSS as a substitute chain extender, both rigidify the hard-block phase of the PU and significantly alter both the phase morphology, mixing and structure of the inter-phase domains. These observations are supported by more classical AFM and DSC morphological characterization of the POSS-PU hybrid systems which show significant re-structuring of the phase domain structure of the PU and ordering of the crystalline hard-block domains. This work demonstrates the application of a multi-scaled experimental approach towards understanding the effects of three-dimensional, nano-scale cage moieties on the already complex phase structure of segmented polyurethanes. Through these efforts, new insight has been gained into the mechanisms by which low levels of a nano-material such as a cubic sesquioxane, can impact the phase separation and segmental dynamics of block ter-polymer polyurethanes