Organic-inorganic Nanocomposite Films Research Articles

Biosustainable Multiscale Transparent Nanocomposite Films for Sensitive Pressure and Humidity Sensors.

Light weight, thinness, transparency, flexibility, and insulation are the key indicators for flexible electronic device substrates. The common flexible substrates are usually polymer materials, but their recycling is an overwhelming challenge. Meanwhile, paper substrates are limited in practical applications because of their poor mechanical and thermal stability. However, natural biomaterials have excellent mechanical properties and versatility thanks to their organic-inorganic multiscale structures, which inspired us to design an organic-inorganic nanocomposite film. For this purpose, a bio-inspired multiscale film was developed using cellulose nanofibers with abundant hydrophilic functional groups to assist in dispersing hydroxyapatite nanowires. The thickness of the biosustainable film is only 40 μm, and it incorporates distinctive mechanical properties (strength: 52.8 MPa; toughness: 0.88 MJ m-3) and excellent optical properties (transmittance: 80.0%; haze: 71.2%). Consequently, this film is optimal as a substrate employed for flexible sensors, which can transmit capacitance and resistance signals through wireless Bluetooth, showing an ultrasensitive response to pressure and humidity (for example, responding to finger pressing with 5000% signal change and exhaled water vapor with 4000% signal change). Therefore, the comprehensive performance of the biomimetic multiscale organic-inorganic composite film confers a prominent prospect in flexible electronics devices, food packaging, and plastic substitution.

Recent trends on anti-fogging treatments using self-healing hydrophilic/superhydrophilic materials

Anti-fogging treatments have recently attracted increasing attention for a variety of practical applications. Among them, the use of hydrophilic/superhydrophilic materials with self-healing properties has shown great promise due to their high durability and ability to maintain performance over time, even when subjected to severe physical/chemical damages. This feature letter outlines the latest research trends in anti-fogging treatments using such promising materials. First, the current state-of-the-art in this field is briefly reviewed, followed by our recent development of self-healing organic–inorganic nanocomposite films that exhibit durable anti-fogging properties. Finally, future directions in the development of anti-fogging treatments for practical applications are discussed.

Preparation and Characterization of Transparent Polyimide Nanocomposite Films with Potential Applications as Spacecraft Antenna Substrates with Low Dielectric Features and Good Sustainability in Atomic-Oxygen Environments

Optically transparent polyimide (PI) films with good dielectric properties and long-term sustainability in atomic-oxygen (AO) environments have been highly desired as antenna substrates in low earth orbit (LEO) aerospace applications. However, PI substrates with low dielectric constant (low-Dk), low dielectric dissipation factor (low-Df) and high AO resistance have rarely been reported due to the difficulties in achieving both high AO survivability and good dielectric parameters simultaneously. In the present work, an intrinsically low-Dk and low-Df optically transparent PI film matrix, poly[4,4′-(hexafluoroisopropylidene)diphthalic anhydride-co-2,2-bis(4-(4-aminophenoxy)phenyl)hexafluoropropane] (6FPI) was combined with a nanocage trisilanolphenyl polyhedral oligomeric silsesquioxane (TSP-POSS) additive in order to afford novel organic–inorganic nanocomposite films with enhanced AO-resistant properties and reduced dielectric parameters. The derived 6FPI/POSS films exhibited the Dk and Df values as low as 2.52 and 0.006 at the frequency of 1 MHz, respectively. Meanwhile, the composite films showed good AO resistance with the erosion yield as low as 4.0 × 10−25 cm3/atom at the exposure flux of 4.02 × 1020 atom/cm2, which decreased by nearly one order of magnitude compared with the value of 3.0 × 10−24 cm3/atom of the standard PI-ref Kapton® film.

Organic-Inorganic Nanocomposite Film for High-Performance Stretchable Resistive Memory Device.

A compatible organic/inorganic nanocomposite film for a stretchable resistive memory device with high performance is demonstrated using poly(4-vinylpyridine)-block-poly(propyl methacrylate) (P4VP-b-PPMA) with zinc oxide (ZnO) nanoparticle. The PPMA soft segment is designed for reducing the rigidity of the active layer, while the P4VP block serves as a charge-trapping component to induce conductive filament and also a compatible moiety for inorganic nanoparticles through hydrogen bonding. The experimental results show that the P4VP-b-PPMA-based electrical memory device exhibits write-once-read-many-times memory behavior and an excellent ON/OFF current ratio of over 105 with a stable turn-on voltage (Vset ) around -2.0 V and stable memory behavior upon stretching up to 60% strain. On the other hand, P4VP-b-PPMA/ZnO nanocomposite film switches the memory characteristic to the dynamic random access memory behavior. The stretchable memory device prepared from the nanocomposite film can have a stretching durability over 40% strain and up to 1000 times cycling stretch-relaxation test. This work demonstrates a new strategy using nanocomposite films with tunable electrical characteristics and enhanced mechanical properties for stretchable electrical devices.

Heat-resistant insulation film containing clay and wood components

In this paper, we prepared a novel organic–inorganic nanocomposite film with excellent insulation properties relative to the polyimide film in mild-processing conditions. The main component of the film is clay mineral and wood component, i.e., the layered silicate and poly(ethylene glycol)-modified lignin derivatives. In the nanocomposite film, an interlayer of silicate was bound by triethanolamine. Furthermore, the lignin derivatives filled the voids of the layered silicate, producing a defect-free densely packed nanocomposite film. This unique structure of the nanocomposite film provides high-thermal stability, a low thermal expansion coefficient of film consisting of clay and lignin derivatives, low gas transmittance rate, low volume/surface resistivity, and high dielectric breakdown voltage. The obtained nanocomposite film was installed in a planar-type transformer where it acted as an insulation film in the transformer coil with high dielectric breakdown voltage.

Preparation and characterization of boronic acid- functionalized halloysite nanotube/poly(vinyl alcohol) nanocomposites

Organic-inorganic nanocomposite films consisting of surface functionalized halloysite nanotube (HNT) and poly (vinyl alcohol) (PVA) with improved mechanical and thermal properties were prepared. The surface of HNT was modified with boronic acid by two different methods. In the first method, a boronic acid group bearing a triethoxysilane was synthesized and used to modify HNT directly. In the second method, HNT was modified by 3-aminopropyltriethoxysilane (APTES) and 4-formylphenylboronic acid sequentially. The surface-modified HNT was characterized by ζ-potential, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis. The nanocomposite films were prepared by solvent casting, followed by compression molding. The molecular aggregation structure and physicochemical properties were investigated by UV–Vis spectrophotometry, differential scanning calorimetry, wide-angle X-ray diffraction, tensile test, and dynamic mechanical analysis.

Получение гибридных нанокомпозитов на основе наноразмерной целлюлозы и магнитных наночастиц с фотокаталитическими свойствами

A low-temperature solution-based method for the production of hybrid organic-inorganic nanocomposite films based on nanoscale cellulose and magnetic iron oxide nanoparticles (CNC/Fe3O4) was developed. The obtained nanomaterials were investigated by scanning electron microscopy (SEM), dynamic light scattering (DLS), energy dispersive spectroscopy analysis (EDS) and X-ray diffraction analysis (XRD), thermogravimetric analysis (TGA), and FT-IR spectroscopy. The formation of CNC/Fe3O4 nanocomposite was confirmed by the XRD analysis. According to SEM images, Fe3O4 nanoparticles are uniformly distributed on the surface of nanocellulose. The obtained nanocomposite material exhibits photocatalytic activity under visible light and UV irradiation in the rhodamine B degradation reaction. Thus, the developed biocompatible and environmentally friendly hybrid nanomaterials have great prospects of practical application in the field of biomedicine and photocatalysis.

Tuning photoresponsive and dielectric properties of PVA/CdSe films by capping agent change

In the present work, hybrid organic-inorganic nanocomposite films based on poly(vinyl alcohol) (PVA) and CdSe quantum dots synthesized in aqueous medium were prepared without the use of organic solvents, by casting aqueous solutions of both PVA and nanoparticles. The effect of different capping agents employed during quantum dot synthesis on thermal, optical, and dielectric properties of nanocomposites was analyzed, finding that capping agents not only affect the interactions between nanoparticles and polymeric matrix, but also the size and photoluminescence of quantum dots, among other properties. Optical, thermal, dielectric and morphological characterization of nanocomposites has been carried out in terms of UV–vis spectroscopy, spectrofluorometry, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), dielectric relaxation spectroscopy (DRS) and atomic force microscopy, respectively, finding that by the use of different capping agents, final properties of nanocomposites can be tuned, as interactions between PVA and CdSe quantum dots determine their final properties.

Solution-Processed Interfacial PEDOT:PSS Assembly into Porous Tungsten Molybdenum Oxide Nanocomposite Films for Electrochromic Applications.

Electrochromic devices (ECDs) have received increased attention for applications including optoelectronics, smart windows, and low-emission displays. However, it has been recognized that the ECDs with transition-metal oxide (TMO) electrodes possess a high charge transport barrier because of their poor electrical conductivity, which limits their electrochromic performance. In this work, we addressed this limitation by utilizing a conjugated polymer to fabricate an organic-inorganic nanocomposite film that decreases the charge transport barrier of typical TMO electrodes. Using a conventional spray-layer-by-layer (spray-LbL) deposition technique, we demonstrate an electrochromic film composed of porous layers of tungsten molybdenum oxide (W0.71Mo0.29O3) nanorods permeated with an interconnected conductive layer of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS). The introduction of PEDOT:PSS is shown to significantly reduce the charge transport barrier, allowing the nanocomposite W0.71Mo0.29O3/PEDOT:PSS electrode to exhibit significantly improved electrochromic switching kinetics compared with the deposited W0.71Mo0.29O3 films. Furthermore, the optical contrast of the nanocomposite electrode was observed to be superior to both pure PEDOT:PSS and W0.71Mo0.29O3 electrodes, with a performance that exceeded the linearly predicted contrast of combining the pure films by 23%. The enhanced performance of the PEDOT:PSS-intercalated porous W0.71Mo0.29O3 nanocomposite electrodes and the facile synthesis through a spray-LbL method demonstrate a viable strategy for preparing fast assembling high-performance nanocomposite electrodes for a wide variety of electrochemical devices.

The preparation of γ-poly(vinylidene fluoride)/ZnS nanocomposite for energy storage application

Organic-inorganic nanocomposite film composed of poly(vinylidene fluoride) (PVDF) and zinc sulphide nanoparticles (ZnS-NPs) has been prepared. It is observed that composite film can stabilize the γ-phase. The PVDF-ZnS composite film exhibits superior dielectric property (ɛr∼14 at 1 kHz) than those of pure PVDF. Enhanced saturated polarization (Psat ∼0.38 µC cm-2) and remnant polarization values (Pr∼ 0.21 µC cm-2) are obtained in nanocomposite film that indicates to have potential to use as energy storage applications. In addition, ZnS-NPs incorporation also improves dielectric breakdown strength.

Organic–inorganic nanocomposite films made from polyurethane dispersions and colloidal silica particles

Polyurethane/silica nanocomposites were prepared by solution blending of polyurethane water dispersion (PUD) based on polycarbonate macrodiol with colloidal silica aqueous sol LUDOX TMA. Because of mixing PUDs made from linear polyurethane with the nanofiller, only physical polymer/filler type of interface formed by hydrogen bonds was obtained. As a result the materials were possible to reuse after dissolution in acetone followed by dispersion in water. The effect of colloidal silica content on mechanical, thermal, morphological, and swelling properties of obtained films was tested by tensile test, dynamic mechanical thermal analysis, thermogravimertic analysis, scanning electron microscopy, atomic force microscopy, and swelling analyses. The nanocomposites were classified in three groups differing in the internal structure and functional properties: organic matrix filled with inorganic nanofiller (up to 10 wt% of silica), bicontinous systems (25 and 32 wt% of silica) and inorganic matrix filled with polyurethane (50 and 60 wt% of silica). Only small amount of colloidal silica (up to 10 wt%) improves thermo-mechanical properties, smoothes the materials, and suppresses extent of swelling without changing of the films transparency.

Self-assembly and tribological properties of a novel organic–inorganic nanocomposite film on silicon using polydopamine as the adhesion layer

Utilizing the strong coordination interactions between phenolic hydroxyls of polydopamine (Pdop) and silver oxide nanoparticles (Ag2O NPs), Ag2O NPs were successfully assembled on a dual-layer film composed of a polydopamine outer layer and 3-aminopropyltriethoxy silane (APS) sub-layer, on silicon (Si) substrate. The morphologies, structures and chemical compositions of Ag2O NPs and the tri-layer film were confirmed by various instruments, including ultraviolet absorption spectrum (UV), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). Furthermore, the micro adhesion forces and macro tribological performances were evaluated using AFM and UMT-2M tribometer (CETR), respectively. The results indicated that the tri-layer film displays favourable friction reduction and wear resistance ability. Hence, this renders the self-assembly attractive for constructing the multilayer-structure films with favourable tribological performances for nano/microelectromechanical systems (NEMS/MEMS).

Study on Preparation of High-k Organic–Inorganic Thin Film for Organic–Inorganic Thin Film Transistor Gate Dielectric Application

A simple solution-based deposition technique combined with spin-coating is a plausible way to prepare ultra-thin organic–inorganic nanocomposite films. In this study, we describe the spin-coating deposition of a colloidal nanoparticle suspension to obtain an ultra-thin organic–inorganic composite film as a gate insulator for organic thin film transistor (O-TFT) application. To obtain a homogenous organic–inorganic composite film, well-dispersed TiO2 nanoparticles in γ-butyrolactone and polyimide are important; therefore, several dispersants were assessed on the basis of the measurement of the rheological behavior of slurries. The thickness of the organic–inorganic composite film is mainly determined by the speed of spin-coating and viscosity of slurries. An approximately 4000-Å-thick nanocomposite film with homogeneous distribution of TiO2 nanoparticles in polyimide and low roughness was obtained after curing at 200 °C, resulting in a low leakage current density of the nano-composite film, when less than 2 vol % TiO2 nanoparticles were well dispersed in polyimide slurry. The dielectric constant of the organic–inorganic nanocomposite increases with increasing TiO2 content in polyimide, being situated in the range between 4 and 5.

Superhydrophobic surface by immobilization of polystyrene on vinyl-modified titania nanoparticles

The organic–inorganic nanocomposite films were fabricated by grafting polystyrene (PS) onto the vinyltriethoxysilane (VTEOS) modified titanium dioxide nanopowders using free radical polymerization. The composition of the surfaces and the structure for the PS grafted titania (PS-g-TiO2) were examined by infrared spectroscopy, X-ray photoelectron spectroscopy and thermogravimetric analysis, and the rough surface was confirmed by the evaluation of the morphological characteristics of the coating using hybrid particles. The wetting properties of the VTEOS modified titania and PS-g-TiO2 films were investigated, which show the maximum static water contact angles of 160° and 154°, and minimum sliding angles of 3° and 4°, respectively.

Fabrication of continuous mesoporous organic–inorganic nanocomposite films for corrosion protection of stainless steel in PEM fuel cells

The organic–inorganic composite film was deposited on the 304 stainless steel as bipolar plate material for proton exchange membrane fuel cells by spin-coating method. As shown by XRD, N 2 adsorption–desorption and TEM, the composite films exhibit ordered mesoporous structures. The corrosion tests in 0.5 M H 2SO 4 system displayed that, compared with 304SS, the composite films made corrosion potential shifted to positive direction by 250–1000 mV (SCE) and corrosion current decreased by 1–3 orders of magnitude. Wherein, the C-50–60% composite film showed the optimal protective performance, its corresponding potentiostatic polarization process was extremely stable in the simulated fuel cells environment.

Preparation and characterization of Chitosan/Konjac glucomannan/CdS nanocomposite film with low infrared emissivity

Novel organic–inorganic nanocomposite films were prepared with Chitosan (CS), Konjac glucomannan (KGM) and CdS by one-step synthesis. As-prepared films were characterized by IR spectra, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and infrared emissometer (IR). The results indicated that grown CdS dendrites were formed with reaction time of 12 h for Cd 2+ and CS/KGM, and were well dispersed in CS/KGM with an average diameter of 40 nm. The CS/KGM/CdS nanocomposite films had significantly low infrared emissivity. When the mole ratio of CdS to summation of CS&KGM construction units was 1.0 with CdS size of 10–20 nm, the film got the lowest infrared emissivity value of 0.011, which could be attributed to the strong synergism effect existing between CS/KGM and CdS dendrites.

High luminescence, organic–inorganic nanocomposite films with covalently linked 8-hydroxyquinoline anchored to ZnS nanoparticles

A series of transparent, highly fluorescent, organic–inorganic nanocomposite films were prepared by incorporating mercaptoethanol-capped ZnS nanoparticles into a copolymer of trialkoxysilane-capped poly(MMA-co-Hq-CH 2-HEMA) carrying an 8-hydroxyquinoline (Hq) unit, followed by ligand exchange and sol–gel processing. Electron microscopy revelaed that the ZnS nanoparticles were uniformly dispersed in the organic–inorganic hybrid matrix regardless of the content and matrix composition. The hybrid nanocomposites had good optical transparency in the visible region. The nanocomposites that contained the ZnS nanoparticles were stable and displayed high fluorescence emission at 500 nm, which differed from that of hybrid materials obtained by simply blending the zinc ions or bis(8-hydroxyquinoline) zinc compound with the copolymer matrix. Thermogravimetric analysis indicated that the nanocomposite materials had high thermal stability.

Direct electrochemistry and electrocatalysis of horseradish peroxidase immobilized in hybrid organic–inorganic film of chitosan/sol–gel/carbon nanotubes

A hybrid organic–inorganic nanocomposite film of chitosan/sol–gel/multi-walled carbon nanotubes was constructed for the immobilization of horseradish peroxidase (HRP). This film was characterized by scanning electron microscopy. Direct electron transfer (DET) and bioelectrocatalysis of HRP incorporated into the composite film were investigated. The results indicate that the film can provide a favorable microenvironment for HRP to perform DET on the surface of glassy carbon electrodes with a pair of quasi-reversible redox waves and to retain its bioelectrocatalytic activity toward H 2O 2.

The preparation of metal oxygen molecular cluster embedded organic–inorganic nanocomposite and its rectification behaviour

Abstract A metal oxygen molecular cluster compound has been utilized for the preparation of organic–inorganic nanocomposite film by a sol–gel method. The entrapment of these cluster compounds in a composite film has been characterized by various physico-chemical techniques. The entrapped metal oxygen cluster stabilizes its energy levels, which is evidenced from the change in redox potential and band gap. The rectification phenomenon of composite films is attributed to the embedded cluster compounds. The rectification behaviour of the composite film, which is due to the charge transfer from molecular cluster and the electrode, has been studied.

Preparation and characterization of KGM/CdS nanocomposite film with low infrared emissivity

In this research, novel organic–inorganic nanocomposite films of Konjac glucomannan (KGM) and CdS were prepared by one-step synthesis. As-prepared films were characterized by IR, TEM and SEM. The results indicated that hexagonal CdS nanoparticles with the sizes of 10 to 100 nm were well dispersed in KGM. The infrared emissivities of the films were characterized by IR-1 infrared emissivity instrument. As results showed, the KGM/CdS nanocomposite films had significantly lower infrared emissivity (8–14 μm), meanwhile when the size of KGM nanoparticles was between 10 and 20 nm and the mole ratio of CdS to KGM was 1.2:1, the film got the lowest infrared emissivity value of 0.011, which would be attributed to the strong synergism effect existing between KGM and CdS nanoparticles.