Formation Of Hybrid Materials Research Articles

Preparation of photocrosslinked sol-gel composites based on urethane-acrylic matrix, silsesquioxane sequences, TiO2, and Ag/Au Nanoparticles for use in photocatalytic applications

An acid urethane oligodimethacrylate based on poly(ethylene glycol) was synthesized and used in the preparation of hybrid composites containing silsesquioxane sequences and titania domains formed through sol-gel reactions along with silver/gold nanoparticles (Ag/Au NPs) in situ photogenerated during the UV-curing process. The photopolymerization kinetics studied by Fourier transform infrared spectroscopy and photoDSC showed that the photoreactivity of the investigated formulations depends on the amount of titanium butoxide (5–20 wt %) added in the system subjected to UV irradiation. The introduction of 1 wt % AgNO3/AuBr3 in formulations slightly improved the degree of conversion but diminished the polymerization rates. The formation of hybrid materials comprising predominantly amorphous TiO2/SiO2 NPs, with or without Ag/Au NPs, was confirmed through specific analyses. The evaluation of photocatalytic activity demonstrated that the synthesized hybrid films are suitable for the complete removal of organic pollutants (phenolic compounds) from water under UV irradiation (200–350 min) at low intensity (found in the solar radiation). © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 1189–1204

Organometallic exposure dependence on organic–inorganic hybrid material formation in polyethylene terephthalate and polyamide 6 polymer fibers

The effect of exposure conditions and surface area on hybrid material formation during sequential vapor infiltrations of trimethylaluminum (TMA) into polyamide 6 (PA6) and polyethylene terephthalate (PET) fibers is investigated. Mass gain of the fabric samples after infiltration was examined to elucidate the reaction extent with increasing number of sequential TMA single exposures, defined as the times for a TMA dose and a hold period. An interdependent relationship between dosing time and holding time on the hybrid material formation is observed for TMA exposure PET, exhibited as a linear trend between the mass gain and total exposure (dose time × hold time × number of sequential exposures). Deviation from this linear relationship is only observed under very long dose or hold times. In comparison, amount of hybrid material formed during sequential exposures to PA6 fibers is found to be highly dependent on amount of TMA dosed. Increasing the surface area of the fiber by altering its cross-sectional dimension is shown to have little on the reaction behavior but does allow for improved diffusion of the TMA into the fiber. This work allows for the projection of exposure parameters necessary for future high-throughput hybrid modifications to polymer materials.

Macromolecular templates for the development of organic/inorganic hybrid materials

Biominerals and the formation mechanisms of these materials have been studied intensively for decades. Biominerals have attracted much attention from material scientists because these compounds have significant mechanical and optical properties because of their elaborate structures. We believe that novel functional hybrid materials with hierarchical structures are best prepared using abundant elements and mild conditions, similar to the formation of natural biominerals. This review focuses on using an organic (bio)polymer for the formation of these hybrid materials based on CaCO3 and on understanding the formation of new hybrid materials via bio-inspired approaches. The structure–function relationships of biomineralization-related proteins are discussed. Molecular designs to control the properties of the hybrid materials are also described. The combination of experimentation and molecular simulation is also introduced. These studies provide useful ideas for the development of hybrid materials through biomimetic approaches. This review focuses on using an organic (bio)polymer for the formation of organic/inorganic hybrid materials and on understanding the formation of new hybrid materials via bio-inspired approaches. The structure–function relationships of biomineralization-related proteins and molecular designs to control the properties of the hybrid materials are also described. The combination of experimentation and molecular simulation is also introduced. These studies provide useful ideas for the development of hybrid materials through biomimetic approaches.

Relationship between electrical conductivities and structure of hybrid materials derived from mixtures of zinc phosphate glasses with different phosphate-chain lengths and benzimidazole

Here, we report unique anhydrous proton-conducting hybrid materials derived from mixtures of benzimidazole and zinc metaphosphate glass. Benzimidazole, which melts at 170 °C, caused breaking of the phosphate chains in the glasses, resulting in the formation of hybrid materials. In the present work, various hybrid materials were prepared to clarify the effects of parent glass composition on their electrical conductivities. In the case of 53P2O5 · 47ZnO glass, which contains Qp1 and Qp2 and Qp3 groups, the phosphate chains were broken easily to form benzimidazole and Qp0 groups. Qpn, where n is the number of bridging oxygens to neighboring tetrahedral, describes the bonding of PO4 tetrahedron. Hybrids prepared using benzimidazole and 42P2O5 · 58ZnO glass (which contains many Qp1 groups) formed the smallest amounts of the Qp0 group-containing products. The hybrid material prepared with 53P2O5 · 47ZnO glass showed the highest conductivity (e.g., ∼1 mS/cm at 190 °C). The electrical conductivities of the hybrid materials may be related to the amounts of Qp0 group-containing products and benzimidazole.

Formation of novel photoluminescent hybrid materials by sequential vapor infiltration into polyethylene terephthalate fibers

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Preparation and characterization of poly(methyl methacrylate)/SiO2 organic–inorganic hybrid materials via RAFT-mediated miniemulsion Polymerization

Poly(methyl methacrylate)/SiO2 (PMMA/SiO2) organic–inorganic hybrid materials were prepared by traditional free radical polymerization and RAFT polymerization in miniemulsion. Comparison of these two reactions kinetics results indicated the polymerization behavior of methyl methacrylate (MMA) with control of the RAFT mechanism showed controlled/living radical polymerization (CLRP) characteristics. The hybrid materials were characterized by gel permeation chromatography (GPC), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), Fourier transform-infrared spectroscopy (FT-IR) and transmission electron microscopy (TEM). Incorporation of the RAFT agent and SiO2 nanoparticles can effectively improve the thermal properties of PMMA polymers. TEM results showed that part of the SiO2 nanoparticles adsorbed on the surface of the PMMA latex particles and formed hybrid materials with partially wrapped structure.

Hollow metal-organic framework nanospheres via emulsion-based interfacial synthesis and their application in size-selective catalysis.

Metal-organic frameworks (MOFs) represent an emerging class of crystalline materials with well-defined pore structures and hold great potentials in a wide range of important applications. The functionality of MOFs can be further extended by integration with other functional materials, e.g., encapsulating metal nanoparticles, to form hybrid materials with novel properties. In spite of various synthetic approaches that have been developed recently, a facile method to prepare hierarchical hollow MOF nanostructures still remains a challenge. Here we describe a facile emulsion-based interfacial reaction method for the large-scale synthesis of hollow zeolitic imidazolate framework 8 (ZIF-8) nanospheres with controllable shell thickness. We further demonstrate that functional metal nanoparticles such as Pd nanocubes can be encapsulated during the emulsification process and used for heterogeneous catalysis. The inherently porous structure of ZIF-8 shells enables encapsulated catalysts to show size-selective hydrogenation reactions.

Internalization of Silica Nanoparticles into Fluid Liposomes: Formation of Interesting Hybrid Colloids

AbstractThe formation of hybrid materials consisting of membrane‐coated silica nanoparticles (SiNPs) concentrated within small unilamellar vesicles (SUVs) of 1,2‐dioleoyl‐sn‐glycero‐3‐phosphocholine (DOPC) is described. They are formed by a simple self‐assembly process resulting from invagination of the SiNPs into the SUVs and subsequent vesicle fusion, thereby retaining an almost constant size. This process was followed under conditions where it proceeds slowly and could be analyzed in structural detail. The finally formed well‐defined SiNP‐filled vesicles are long‐time stable hybrid colloids and their structure is conveniently controlled by the initial mixing ratio of SiNPs and vesicles.

Internalization of Silica Nanoparticles into Fluid Liposomes: Formation of Interesting Hybrid Colloids

The formation of hybrid materials consisting of membrane-coated silica nanoparticles (SiNPs) concentrated within small unilamellar vesicles (SUVs) of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) is described. They are formed by a simple self-assembly process resulting from invagination of the SiNPs into the SUVs and subsequent vesicle fusion, thereby retaining an almost constant size. This process was followed under conditions where it proceeds slowly and could be analyzed in structural detail. The finally formed well-defined SiNP-filled vesicles are long-time stable hybrid colloids and their structure is conveniently controlled by the initial mixing ratio of SiNPs and vesicles.

New mono- and diethynylsiloxysilsesquioxanes--efficient procedures for their synthesis.

Ethynyl-substituted siloxysilsesquioxanes are promising building blocks for a wide range of substances based on a POSS/DDSQ core, especially for (oligo-)polymer syntheses and modifications (the formation of hybrid materials with interesting photophysical and mechanical properties). In this study, we report on a series of new mono- and diethynylsiloxysilsesquioxanes formed via an efficient and highly selective one-pot process from silsesquioxanes with reactive Si-OH groups based on sequential condensation, hydrolysis, chlorination and substitution reactions. All newly synthesized compounds were isolated and characterized by spectroscopic methods.

Amorphous Hierarchical Porous GeOx/Reduced Graphene Oxide Composite As a High-Performance Anode Material for Lithium Ion Batteries

The conventional graphite anode is still insufficient to meet the demand due to its low theoretical specific capacity(372 mAhg-1). Compared to the graphite, the high surface-to-volume ratio and open porous system of graphene shows great advantages:i) fast ion transport enabling the high rate capability, which is an obstacle for graphite with microsize bulk lithium diffusion; ii) the large surface areas of graphene can provide more electrochemical reaction active sites for energy storage. Meanwhile, Graphene is an excellent substrate to host active nanomaterial for energy applications due to its high conductivity, large surface area, structural flexibility, and chemical stability.1,2Overall, the superior electronic conductivity and mechanical properties of graphene make it suitable for fabrication into high-performance composites with other anode materials for LIBs. Recently, Alloy-type anodes (Si, Ge, Sn, Sb, etc.) have attracted much attention due to their higher Li storage capacity than the graphite anode that is currently used in Li-ion batteries. Compared with the silicon etc., Germanium has high theoretical capacity (1384 mAh/g), good lithium diffusivity (400 times faster than in silicon), and high electrical conductivity (104 times higher than silicon).3 However, the practical usage of Ge as an anode material is hindered by dramatic volume changes (∼300%) caused by insertion/extraction of lithium ions, which results in crack and pulverization, and loss of electrode contact.4 Herein, we developed a facile synthesis method (solution-phase reactions) to form hybrid materials of amorphous hierarchical porous GeOx whose primary particles are 3∼7 nm diameter anchored on reduced grapheme oxide (RGO) sheets for lithium ion battery applications. The high rate performance of mesoporous GeOx/RGO composite is attributed to (1) the amorphous hierarchical porous GeOx whose primary particles are 3∼7 nm diameter anchored on conducting RGO stabilize the cycling performance and rate capability; (2)fast charge transfer reaction at the large interfacial area of RGO between hybrid electrode and liquid electrolyte. Acknowledgements This work is supported by the Project of the Ningbo 3315 International Team of Advanced Energy Storage Materials, China Postdoctoral Science Foundation funded project.

Sulfonated Aromatic Polymers as Proton-Conducting Solid Electrolytes for Fuel Cells: a Short Review

Abstract This review describes main strategies for the development of sulfonated aromatic polymers (SAP) with optimal properties for medium temperature (90–120 ºC) polymer electrolyte membrane fuel cell applications. SAP are promising economical polymer electrolytes, but there still exist some challenges about these materials due mainly to excessive swelling in water, poor mechanical strength and low dimensional stability. Here, the state-of-the-art of SAP is reviewed and the main focus will be directed to properties of SAP, including proton conductivity, water uptake, mechanical strength, permeability. Especially three approaches to improve the performances are addressed: the formation of copolymers, the formation of hybrid materials and the polymer reticulation.

Multifunctional three-dimensional macroporous nanoelectronic networks for smart materials

Seamless and minimally invasive integration of 3D electronic circuitry within host materials could enable the development of materials systems that are self-monitoring and allow for communication with external environments. Here, we report a general strategy for preparing ordered 3D interconnected and addressable macroporous nanoelectronic networks from ordered 2D nanowire nanoelectronic precursors, which are fabricated by conventional lithography. The 3D networks have porosities larger than 99%, contain approximately hundreds of addressable nanowire devices, and have feature sizes from the 10-μm scale (for electrical and structural interconnections) to the 10-nm scale (for device elements). The macroporous nanoelectronic networks were merged with organic gels and polymers to form hybrid materials in which the basic physical and chemical properties of the host were not substantially altered, and electrical measurements further showed a >90% yield of active devices in the hybrid materials. The positions of the nanowire devices were located within 3D hybrid materials with ∼14-nm resolution through simultaneous nanowire device photocurrent/confocal microscopy imaging measurements. In addition, we explored functional properties of these hybrid materials, including (i) mapping time-dependent pH changes throughout a nanowire network/agarose gel sample during external solution pH changes, and (ii) characterizing the strain field in a hybrid nanoelectronic elastomer structures subject to uniaxial and bending forces. The seamless incorporation of active nanoelectronic networks within 3D materials reveals a powerful approach to smart materials in which the capabilities of multifunctional nanoelectronics allow for active monitoring and control of host systems.

Characterization of New Inorganic-Organic Composites Based on Mesoporous Silica and Vinyl Acetate

New polymer composites were synthesized by a new approach: radical polymerization in an ultrasonic field of the vinyl acetate inside the silica pores. The systems were extensively characterized by different techniques: X-ray photoelectron spectroscopy (XPS), gel permeation chromatography (GPC), thermogravimetric analysis (TGA), derivative thermogravimetry (DTG), dynamic mechanical analysis (DMA), and scanning electron microscopy (SEM). The formation of hybrid materials was proved by XPS. The molecular weight of the entrapped polymer in the cavities of the inorganic structure was assessed by GPC. The thermal properties of the composites were determined by TGA/DTG and DMA.

Poly(vinyl butyral)-zirconia hybrid films formed by sol-gel process

A sol-gel process has been successfully utilized to form hybrid materials of poly(vinyl butyral) (PVB) and zirconium dioxide (zirconia). The gelation occurred due to the interaction between remaining hydroxyl group of PVB and zirconia. The hybrids showed good optical transparency and significant improvement in Young's modulus, dynamic mechanical property, abrasion resistance and impact resistance. The glass transition temperature of PVB shifted to higher temperatures by hybridization of PVB and zirconia.

Fabrication and Characterization of Regenerated Cellulose/TiO<sub>2</sub> Nanocomposite Hybrid Fibers

Nanocomposite fibers are one of the most fascinating materials with broad applications. In the present work，nanocomposite fibers were prepared by a low-cost, simple, and “green” process. The nanocomposite of cellulose acetate/TiO2 was realized by combining the functional oxide material TiO2 with the regenerating electrospun cellulose acetate fibers. The structural features were characterized by scan electron microcopy, transmission electron microscopy and infrared spectrum. The compositing mechanism was proposed. The surface functionalized hydroxyl by the regenerating process plays an important role for the formation of hybrid material.

A New Step Towards Solid Base Catalysis: Azidoproazaphosphatranes Immobilized in Nanopores of Mesoporous Silica

AbstractHeterogeneous basic catalysts derived from proazaphosphatranes, known as Verkade’s superbases, were prepared for the first time by covalent immobilization onto SBA‐15 silica. In order to introduce the tether to the surface, three siloxane‐containing azido derivatives of the proazaphosphatranes were first synthesized (2a–c) which after post‐synthetic grafting onto silica support led to the formation of hybrid materials of different basicity and steric properties, 2a–c@SBA‐15. These latter were fully characterized using a wide variety of molecular and solid‐state techniques to determine their structural and textural properties. These new solid base catalysts were then evaluated in the Diels–Alder reactions of anthrone and 3‐hydroxy‐2‐pyrone with two electron‐deficient dienophiles, N‐methylmaleimide and dimethyl fumarate. In general, high activity and selectivity were obtained depending on the catalytic species, the performance decreasing in the order methoxybenzyl>neopentyl>methyl azidophosphatrane. Catalyst recycling was studied for the best catalyst, the methoxybenzyl derivative, 2c@SBA‐15, and it was shown that the catalyst could be re‐used up to 3 cycles before any loss of activity could be detected.

Single-step synthesis and characterization of single-walled carbon nanohorns hybridized with Pd nanoparticles using N 2 gas-injected arc-in-water method

Single-walled carbon nanohorns (SWCNHs) hybridized with palladium (Pd) nanoparticles were synthesized by a single-step gas-injected arc-in-water method (GI-AIW) with a Pd wire inserted inside the anode hole. In the arc zone, carbon and Pd were vaporized simultaneously, leading to the formation of hybrid material of SWCNHs and Pd nanoparticles due to effective quenching. Based on TEM and CO chemisorption analyses, Pd nanoparticles were found to be embedded inside SWCNH aggregates. The size of Pd nanoparticles, determined by X-ray diffraction, was in the range of 3–6 nm when Pd wires with diameters of 0.1 and 0.3 mm were used. Using a Pd wire with a diameter larger than 0.5 mm results in larger Pd nanoparticles which tend to be exposed to the outer surface of the hybrid material. According to thermogravimetric analyses, the weight fraction of Pd nanoparticles is increased by increasing the Pd wire diameter although the yield of Pd nanoparticles decreased. SWCNHs hybridized with dispersed Pd nanoparticles, synthesized with 0.1 mm Pd wire, exhibited strong anti-oxidation resistance with a highly graphitic structure.

Effects of the concentrations of precursor and catalyst on the formation of monodisperse silica particles in sol–gel reaction

The monodispersed hybrid silica particles could be synthesized through the one-step sol–gel reaction with organosilane (3-mercaptopropyl trimethoxysilane, MPTMS) in aqueous solution. In this study, the effects of the concentrations of organosilane and the catalyst ((NH 4OH) on the formation of silica particles were investigated. For the first time we reported the successful one-step synthesis of monodisperse hybrid silica particles using organosilane chemicals in the previous study. In order to obtain better insight about the reaction processes, the silica particles were prepared in the presence of various concentrations of MPTMS and NH 4OH. On the basis of the experimental results, it was found that particle size increases as the concentration of organosilane increases. Also, as the concentration of catalyst increases, the diameter of these monodisperse particles decreases significantly. This research can contribute to a new broad avenue for the surface functionalization and hybrid material formation with various sizes.

Investigation of the structure of chitosan hybrid systems by pH-sensitive nitroxyl radical

Hybrid organo-inorganic materials based on the chitosan-SiO2, chitosan-Al2O3, and chitosancellulose systems are prepared. The structure of the surface is studied by means of EPR spectroscopy using the stable pH-sensitive nitroxyl radical, 4-dimethylamino-2-ethyl-5,5-dimethyl-2-pyridine-4-yl-2,5-dihydro-1H-imidazole-1-oxyl as adsorbed probe molecules, and the processes that occur during the formation of hybrid materials are considered.