Polyurethane–imide–polyhedral oligomeric silsesquioxane hybrid nano-composites

Journal of Thermal Analysis and Calorimetry - In order to improve thermo-stability of polyurethane (PU), both imide group and polyhedral oligomeric silsesquioxane (POSS) were introduced into PU...     

Preferred-handed helical conformation in organic–inorganic hybrid block copolymers with well-controlled stereoregularity

A novel block copolymer containing polyhedral oligomeric silsesquioxanes (POSS) features a well-controlled stereoregularity, that is, isotactic polymethacrylate-functionalized POSS-b-polymethyl methacrylate (it-PMAPOSS-b-PMMA), was prepared via controlled-anionic polymerization. The stereoregularity of each segment in the it-PMAPOSS-b-PMMA is evaluated using nuclear magnetic resonance (NMR) spectroscopy, which reveals an isotactic configuration in both the PMAPOSS and PMMA segments. The secondary structure of it-PMAPOSS-b-PMMA in a mixture with a small chiral dopant is clarified with electronic circular dichroism and vibrational circular dichroism measurements. By adding a chiral dopant, a controlled preferential helical conformation of the unilateral segment in achiral it-PMAPOSS-b-PMMA is achieved.     

Sedimentation analysis of organic–inorganic hybrid colloids

Hybrid organic–inorganic latex particles are synthesized to combine the beneficial properties of the constituents which thus lead to synergistic improvement in the properties. The properties of hybrid particles are dependent on the successful hybridization process, thus controlling or tuning of such processes by effective characterization is immensely important. Analytical ultracentrifugation provides these characterization possibilities owing to its high statistical capability and ability to characterize multiple parameters. The use of different detection methodologies can help in generating valuable information on the overall size and density distributions of the particles. Apart from that, it is also possible to quantify the presence of any free polymer and inorganic particles in the hybrid latex which would affect the properties of hybrid latexes. By following the densities of the pure and hybrid particles, it is also possible to quantify the amounts of the constituent phases in the hybrid particles. The density gradients generated in preparative ultracentrifugation also provide additional possibilities for the characterization of the hybrid particles which have densities higher than the measurable range in the analytical ultracentrifuge. Evolution of hybrid particles can also be studied as a function of time. It also provides advantage of separation of the various fractions for further characterization.     

Heat resistant and transparent organic–inorganic hybrid materials composed of N-allylmaleimide copolymer and random-type SH-modified silsesquioxane

A thermally stable and transparent copolymer (PAED) composed of N-allylmaleimide, N-(2-ethylhexyl)maleimide, and diisobutylene as the repeating units was produced by radical copolymerization in the presence of an azo initiator in chloroform at 60 °C. The thiol–ene reaction between the allyl groups included in the side chain of PAED and the mercapto groups (SH) included in a random-type SH-modified silsesquioxane (SQ) as the crosslinker provided PAED–SQ hybrid materials upon heating. The reaction process for this thermal curing was monitored from the intensity changes of characteristic peaks by IR spectroscopy as well as the gravimetric determination of the isolated insoluble fractions. The thermal, optical, and mechanical properties of the hybrids were investigated. The onset and maximum decomposition temperatures were 322–369 °C and 399–431 °C, respectively. The weight residue at 800 °C was 16–40 wt%, which depended on the amount of the SQ content in the feed. These organic–inorganic hybrid materials were highly transparent and exhibited refractive index of 1.522–1.524 and Abbe number of 40.0–45.8. The tensile test and dynamic mechanical analyses were also carried out to investigate the mechanical properties and the network structures of the hybrids. The addition of triallylisocyanurate (TAIC) to the curing system efficiently improved the conversion of the allyl and SH, leading to the more dense network structure and the higher strength and hardness of the cured hybrids. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 2294–2302     

Development of a highly robust solid phase microextraction fiber based on crosslinked methyl methacrylate–polyhedral oligomeric silsesquioxane hybrid polymeric coating

A novel solid-phase microextraction (SPME) fiber was prepared by polymerization of an organic–inorganic hybrid polymeric coating on an anodized and derived Ti wire, and applied for the analysis of polycyclic aromatic hydrocarbons from environmental samples followed by high performance liquid chromatography (HPLC) analysis. A polyhedral oligomeric silsesquioxane (POSS) reagent containing methacryl substituent groups was used as an organic–inorganic hybrid cross-linker, and copolymerized with methyl methacrylate (MMA) to fabricate the hybrid coating via thermally initiated free radical polymerization in a glass capillary mold. The prepared fiber can be easily withdrawn from the glass capillary mold by controlling the polymerization conditions, especially polymerization solvent. A homogeneous and porous coating with thickness of about 100 μm was achieved using ethanol as polymerization solvent at the mass ratio of MMA to POSS as 1:0.5. High chemical and mechanical stability, as well as excellent durability for more than 100 times extractions with almost undiminished extraction efficiency were achieved due to the chemical immobilization and crosslinked hybrid coating. The proposed fiber showed much better extraction performance than the 100 μm commercial polydimethylsiloxane fiber for extracting PAHs from aqueous sample. The developed SPME-HPLC method for the determination of PAHs using the MMA–POSS hybrid coating achieved good linearity with good correlation coefficients (R = 0.991–0.999) and low detection limits in the range of 0.006 to 0.05 ng mL⁻¹ (S/N = 3). The proposed fiber was successfully applied to the extraction of PAHs from environmental water samples with recoveries of 82–104% for river water, 83–103% for pool water, and 79–98% for wastewater, respectively.     

Research progress on hybrid organic–inorganic perovskites for photo-applications

Hybrid organic–inorganic perovskite materials have attracted significant attention of most researchers in recently years, which is ascribed to the superior photoelectric properties, such as the suitable band gaps for harvesting sunlight, and exhibit high optical adsorption, high charge-carrier lifetimes and long diffusion lengths. The photodetectors, light-emitting diodes, solar cells and photocatalysts represent the remarkable applications for the hybrid organic–inorganic perovskite materials. Herein, we review the recent progress of hybrid organic–inorganic perovskite-based photodetectors, light-emitting diodes, solar cells and photocatalysts. The challenges and outlook for the hybrid organic–inorganic perovskite-based photodetectors, light-emitting diodes, solar cells and photocatalysts are considered.     

Effect of diphenyldiethoxysilane on the self-organized formation of nanocrystalline layered organosilicates in organic–inorganic hybrid films

Hybrid organic–inorganic films containing layered organosilicate nanocrystals have been obtained through self-organization from aqueous precursor sols containing 3-glycidoxypropyltrimethoxysilane. Diethoxydiphenylsilane has been added, in different amounts, to the precursor sol containing 3-glycidoxypropyltrimethoxysilane to prepare hybrid films with the ordered nanostructures. The effect of aging time of the precursor sol has been studied preparing different samples from sols aged up to 8 days; the formation of crystalline layered films has been observed in the samples obtained from sols of higher aging time. The hybrid films have been characterized by gracing incidence X-ray diffraction, Raman and Fourier transform infrared spectroscopy, transmission electron microscopy and UV–Vis spectroscopy. The change of the surface contact angle as a function of sol aging time and composition has been also measured. The capability of the films to be used in devices through lithographic techniques has been tested by writing the films with direct exposition to deep X-ray lithography and soft lithography with micromolds; patterns of different geometries with a thickness up to 100 μm have been obtained.     

Phosphorus-doped organic–inorganic hybrid silicon coating for improving fire retardancy of polyacrylonitrile fabric

Journal of Sol-Gel Science and Technology - In this study, in order to increase the flame retardancy of polyacrylonitrile fiber fabric, an organic–inorganic hybrid silane coating doped with...     

New organic–inorganic hybrid structure based on paradodecatungstate clusters and imidazolium cations

An organic–inorganic hybrid material based on paradodecatungstate anions and imidazolium cations, Na₂(HIm)₈(H₂W₁₂O₄₂)·10H₂O (HIm: imidazolium), has been synthesized under mildly acidic conditions. This compound was characterized by single-crystal X-ray diffraction, IR and UV–visible spectroscopies, and thermogravimetric and differential thermal analyses. The compound crystallizes in the triclinic P-1 space group with a = 11.6945(8) Å, b = 12.4782(6) Å, c = 14.0952(9) Å, α = 106.041(3)°, β = 109.338(2)°, γ = 100.249(3)°, V = 1781.0(3) Å³, and Z = 2. The crystal structure exhibits an infinite 1D inorganic structure built from [H₂W₁₂O₄₂]^10? clusters and sodium cations; adjacent chains are further joined up by hydrogen-bonding interactions between protonated imidazole cations, water molecules, and polyoxoanions, to form a 3D supramolecular architecture.     

Structure and surface properties of fluorinated organic–inorganic hybrid films

Fluorinated organic–inorganic hybrid films were prepared by sol–gel process from tridecafluoroctyltriethoxysilane (PFAS), 3-glycidoxypropyltrimethoxysilane, and tetraethoxysilane (TEOS). It has been found that the fluorinated hybrid films possessed fluorinated side chains originating from PFAS as top layer, and silica network as bottom layer, which had very low surface energy and could be used as water repellent functional coatings. The outermost layer of the water-repellent film may be fully covered by the perfluoroalkyl side chains as the molar ratio of PFAS/TEOS increases up to about 0.005:1. The addition of BPA can enhance the cross-link density of fluorinated hybrid films, and make more perfluoroalkyl groups enriching at the coating film-air interface to lower the surface free energy. However, the improvement of the cross-link density of fluorinated hybrid films tends to exhibit brittleness and micro-cracks. Consequently, it can be concluded that a small BPA additive content is preferred for the formation of fluorinated hybrid films with a smooth surface and less detectable cracks.     

Synthesis and properties of organic–inorganic hybrid liquid crystal gels

Organic–inorganic hybrid liquid crystal (LC) gels have been synthesised by the thiol-ene reaction of a multifunctional cyclic siloxane, 1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane (TVMCTS) and alkane dithiols, 1,6-hexanedithiol (HDT) or 1,9-decanedithiol (DDT), in LC matrices, 4-cyano-4?-pentylbiphenyl (5CB) or 4′-n-octyl-4-cyano-biphenyl (8CB). The LC gels were prepared in an isotropic phase at 70°C or mesophases at 25°C using radical initiators. The phase transition temperatures from a mesophase to an isotropic phase of the resulting gels were lower than those of the original LCs. The gels containing 8CB (8CB gels) prepared at 25°C showed two phase transitions: smectic-to-nematic and nematic-to-isotropic transitions. By contrast, the 8CB gels synthesised in the isotropic phase showed only one phase transition from smectic phase directly to isotropic phase. Reaction conversions in the LC gels prepared at 70°C were higher than that in the gels prepared at 25°C. Scanning microscopic light scattering analysis of the LC gels cleared homogeneous small size mesh with a small amount of large defect. Polarisation micrographs of the LC gels showed framed optical textures derived from the LC molecules at room temperature. The LC gels containing more than 90 wt% of LC showed electro-optic response.     

Three organic–inorganic hybrid complexes based on the Wells–Dawson polyoxoanion

Three new organic–inorganic hybrid complexes based on the Wells–Dawson polyoxoanion, namely (H₂bpp)[Ni₂(bpp)₂(H₂O)₄(P₂W₁₈O₆₂)]·H₂O 1, [Cu₆(Hbpy)₆(bpy)₃(P₂W₁₈O₆₂)₂]·2H₂O 2 and (Him)₅[Cu(im)₂(P₂W₁₈O₆₂)]·4H₂O 3 [bpp = 1,3-bis (4-pyridyl) propane, bpy = 4,4′-bipyridine, im = imidazole] have been synthesized and characterized. Complex 1 exhibits a three-dimensional (6, 3)-connected framework with anatase topology constructed from [α-P₂W₁₈O₆₂]⁶⁻ clusters and [Ni(bpp)]²⁺ fragments. Each [α-P₂W₁₈O₆₂]⁶⁻ anion links to six nickel atoms through six terminal oxygen atoms from four polar and two equatorial WO₆ octahedra, which shows a novel coordination mode of a Wells–Dawson cluster with a transition-metal atom. Complex 2 displays an interesting one-dimensional double-chain structure built from [α-P₂W₁₈O₆₂]⁶⁻ clusters and [Cu₂(bpy)(Hbpy)₂]²⁺ fragments. To our knowledge, complex 2 represents the first double-chain organic–inorganic hybrid complex based on a Wells–Dawson-type cluster. Complex 3 possesses a one-dimensional zigzag chain structure constructed from [α-P₂W₁₈O₆₂]⁶⁻ anions and [Cu(im)₂]⁺ units through weak Cu···O interactions.     

TEOS/HDTMS inorganic–organic hybrid compound used for stone protection

Inorganic–organic hybrid crack-free xerogels were obtained by using a surfactant n-octylamine as a catalyst containing tetraethoxyorthosilicate (TEOS) and hexadecyltrimethoxysilane as an additive. We studied the effect of gelling time and sol pH on n-octylamine concentration. The organic modification was confirmed by infrared spectroscopic studies, and the hydrophobicity of the coating was tested by the contact angle measurements. The stone surface morphology of sample treated with hybrid sol was characterized. The results show the hybrid gel network exhibits a larger pore size than the gel containing exclusively the silica from TEOS. After the limestone’s surface was modified by hybrid sol, the contact angle of limestone increased from 58° to 123°. The protective performance evaluated by its ability to resist acid rain reveals that the protective effects are satisfied.     

Influence of organic corrosion inhibitors on the corrosion performance of organic–inorganic hybrid coatings applied on aluminium alloy

The proposed work aims to develop and study sol–gel derived anticorrosion films for aluminium. To further improve performance of these films, organic corrosion inhibitors were incorporated into the films. The organic–inorganic hybrid films with and without corrosion inhibitors were deposited on an aluminium substrate by dip coating. The films were characterized by electrochemical impedance spectroscopy (EIS), DC polarisation techniques, and neutral salt spray test to evaluate their anticorrosion properties. This study shows that very low and very high MBT concentrations deteriorate the corrosion performance of coatings, and consequently, there is an optimum concentration of MBT. EIS results revealed a higher corrosion inhibitive activity of 2-mercaptobenzothiazole (MBT) compared to that of 2-amino-5-methylthiazole and 1,2,3 benzotriazole.     

Improvement of the bioactivity of organic–inorganic hybrid aerogels/wollastonite composites with TiO2

Organic–inorganic hybrid aerogels containing P and Ti have been synthesized by supercritical drying of alkogels prepared by hydrolysis and poly-condensation of metalo-organic precursors under high-power ultrasound. These materials become bioactive when doped with Ca. Wollastonite particles (CaSiO₃) were added as an active phase, instead of incorporating Ca into the aerogel atomic network. These particles had previously been precipitated and were then added to the sol. The aerogels were studied by Fourier transform infrared analysis, scanning electron microscopy coupled with energy dispersive spectroscopy and X-ray diffraction and N₂ adsorption. The stress–strain behaviours were evaluated under compression to obtain the Young’s modulus. It was found that the incorporation of TiO₂ into wollastonite-P₂O₅ hybrid aerogels increased their capacity to form apatite and, consequently, improving their bioactive response.     

Naked eye detection of cadmium using inorganic–organic hybrid mesoporous material

A novel and low-cost optical sensor for the naked eye detection of Cd²⁺in aqueous media based on mesoporous silica containing 4-(2-pyridylazo)resorcinol (PAR) as a probe molecule anchored by N-trimethoxysilylpropyl-N,N,N-trimethylammonium chloride (TMAC) was prepared. The effects of various factors such as pH, solvent volume, temperature, reaction time, amount of the material, and the presence of various ions were studied in order to optimize operating conditions. The detection was based on the color change of PAR from orange-yellow to purple as a result of complexation with Cd²⁺. The intensity of the Cd-PAR complex varies linearly with the Cd²⁺concentration, from zero to 1.78×10⁻⁷ mol dm⁻³. The detection and quantification limits for the method when determining Cd²⁺ were 1.75×10⁻⁸ and 5.77×10⁻⁸ mol dm⁻³, respectively, with a correlation coefficient of 0.99. Good chemical stability of the material was observed for a period of five months. The developed sensor was applied to the analysis of various industrial effluents and tap water samples. Electronic supplementary material Supplementary material is available for this article at