Nanoparticle Hybrid Films Research Articles

Enhanced Electrical Conductivities of Transparent Double-Walled Carbon Nanotube Network Films by Post-treatment

We investigated the electrical conductivities of double-walled carbon nanotube (DWNT) network films upon post-treatment via HNO3 or gold ions, particularly with respect to their potential use as transparent conducting films. Post-treatment of DWNT films with HNO3 and deposition of gold nanoparticles, respectively, resulted in a significant decrease of the electrical resistance, while the initial value of the transmittance of pristine-DWNT films was maintained. The DWNT-Au nanoparticle hybrid films exhibited the best transmittance-conductivity performance among the evaluated network films, i.e., pristine-SWNT films, pristine-DWNT films, SWNT-Au nanoparticle hybrid films, and HNO3-treated DWNT films. The electrical behaviors of the gold nanoparticle-coated and HNO3-treated DWNT films were examined by an analysis of the work functions of the DWNT films. The DWNT-Au nanoparticle hybrid films are expected to be applicable to transparent electrodes of various optoelectronic devices such as solar cells, light-em...

Patterning of Layer-by-Layer Assembled Organic−Inorganic Hybrid Films: Imprinting versus Lift-Off

Layer-by-layer (LbL) assembled organic-inorganic poly(acrylic acid) (PAA)/poly(allylamine hydrochloride) (PAH)/ Au nanoparticle hybrid films are patterned by using Norland Optical Adhesive 63 (NOA 63) polymer molds. Depending on the rigidity of the hybrid films, their patterning can be realized by a room-temperature imprinting or lift-off process. For [(PAA/PAH)1-(Au nanoparticle/PAH)3]*10 and [(PAA/PAH)3-(Au nanoparticle/PAH)3]*5 films which have a low content of Au nanoparticles, the films can be imprinted at room temperature to form patterned films with large areas because of the compressibility and fluidity of the films under high pressure. The Au nanoparticle/PAH films, which have an extremely high content of Au nanoparticles and are fragile, can be patterned by a lift-off process during which the film contacted with the NOA 63 mold was peeled off because of the strong adhesion between the film and the mold and the fragility of the film. The complementary room-temperature imprinting and lift-off methods with polymer NOA 63 molds provide facile and general ways to pattern LbL assembled organic-inorganic films with various film compositions.

ZnO/poly(9,9-dihexylfluorene) based inorganic/organic hybrid ultraviolet photodetector

Solution processed inorganic/organic hybrid films of ZnO nanoparticles and poly(9,9-dihexylfluorene) (PFH) are sandwiched between two electrodes to form bulk heterojunction in this letter. The devices obtained show high ultraviolet photo-to-dark current ratio of about three orders of magnitude for −1V bias with a relatively fast response speed of less than 200ms after aging in air for enough time. The spectral response covers 300–420nm, with its peak locating around 335nm. Those results indicate that the ZnO/PFH hybrid devices might be used as low-cost UV optical switches or photodetectors.

Fabrication, characterization, and application of potentiometric immunosensor based on biocompatible and controllable three-dimensional porous chitosan membranes

A novel three-dimensional porous chitosan membrane material was prepared as a matrix to encapsulate hepatitis B surface antibody (HBsAb) for fabrication of immunosensors. The porous chitosan matrix was prepared by electrodepositing a designer nanocomposite solution of chitosan-encapsulated silica nanoparticle hybrid film on an ITO electrode, and then removing the silica nanoparticles with HF solution. Using HBsAb as a model, the potentiometric immunosensor was constructed by linking HBsAb molecules to the three-dimensional porous chitosan film using glutaraldehyde as a cross-linker. Scanning electron microscopy was used to investigate the surface morphology of the three-dimensional porous chitosan films. Cyclic voltammograms and electrochemical impedance spectroscopy were used to probe the interfacial properties of the immunosensor. Results showed that the fabricated immunosensor with three-dimensional porous structure possessed high surface area, good mechanical stability, and good hydrophilicity, which provided a biocompatible microenvironment for maintaining the bioactivity of the immobilized protein and increased the protein loading. Therefore, the present immunosensor exhibits a wide linear range from 6.85 to 708 ng mL −1 with a low detection limit of 3.89 ng mL −1 for the detection of hepatitis B surface antigen (HBsAg). This work implied that the biocompatible and controllable three-dimensional porous chitosan membrane possessed potential applications for biosensing.

Fluorescence spectra of poly(di-n-hexylsilane)/TiO2 nanoparticle hybrid film

The interaction between poly(di-n-hexylsilane) (PDHS) and TiO2 nanoparticle was studied based on the temperature dependence of the fluorescence of a PDHS/TiO2 nanoparticle hybrid film. The polysilane is a suitable probe to investigate a guest polymer–host matrix interaction because the photophysical properties of polysilanes remarkably depend on the conformation of the σ-conjugated Si–Si chain. The PDHS/TiO2 nanoparticle hybrid film showed a fluorescence band assigned to a disordered structure even at 80K whereas only the fluorescence band of an ordered structure was observed for the PDHS film at 80K. The disordering of the Si–Si main chain was explained by the perturbation of the n-hexyl side chain in the neighborhood of the TiO2 nanosurface. The non-radiative deactivation of the excited state via the disorder-induced local potential minima was suggested by the temperature dependence of the fluorescence intensities of the disordered and ordered structures in the temperature region from 80 to 160K.

Highly Sensitive Optical Detection of Humidity on Polymer/Metal Nanoparticle Hybrid Films

Porous metal films for optical humidity sensing were prepared from copper nanoparticles protected by a 2-3 nm carbon coating, a silicon tenside, and a polymeric wetting agent. Exposure to water or solvent vapor revealed an exceptional sensitivity with optical shifts in the visible light range of up to 50 nm for a change of 1% in relative humidity. These properties could be attributed to a combination of surface plasmon resonance effects at low humidity and thin film interference at higher water or solvent concentration in the surrounding air. The simple concept and use of ultra-low-cost materials suggests application of such porous metal-film-based optical humidity sensors in large-scale applications for food handling, storage, and transport.

Preparation of Polyimide/Inorganic Nanoparticle Hybrid Films by Sol–Gel Method

In this study polyimide/inorganic silica–alumina nanoparticle hybrid films are first prepared by sol–gel method to find a promising method for enhancing thermal property and other properties. Silica sol and alumina sol starting from tetraethoxysilicane (TEOS) and aluminum isopropylate (AIP) are doped in a solution of poly (amic acid). The hybrid films are obtained by a stepwise heating method. The structure, micro-morphology, and thermal properties of the films are characterized by Fourier transform infrared (FTIR), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). The micrographs show uniform distribution of club shaped particles in the films containing silica and alumina. The micrographs of polyimide/silica hybrid films revealed sphericity and uniform distribution of particles. Al2O3 particles are poorly dispersed and are prone to agglomerate in the polyimide/alumina hybrid films. Moreover, there are chemical bonds between inorganic and organic phases in the hybrid films. The thermodecomposition temperature of the hybrid films is also improved markedly after the addition of silica and alumina nanoparticles.

In situ immobilization of glucose oxidase in chitosan–gold nanoparticle hybrid film on Prussian Blue modified electrode for high-sensitivity glucose detection

An improved amperometric glucose biosensor was constructed by in situ incorporating glucose oxidase (GOD) within the electrodeposited chitosan–gold nanoparticle (chitosan–AuNP) hybrid film on a Prussian Blue (PB) modified electrode. The method is simple and controllable. It combined the merits of in situ immobilizing biomolecules in the chitosan–AuNP hybrid film by electrochemical method and the synergic catalysis effects of PB and GOD molecule. Scanning electron microscopy showed that the chitosan–AuNP hybrid film was homogeneous with small pores, which improved the stability and sensitivity of the biosensor. The biosensor prepared under optimal conditions showed fast response time (3 s), high sensitivity (69.26 μA mM −1 cm 2), long-term operational stability, good suppression of interference and low detection limit (6.9 × 10 −7 M). A linear calibration plot was obtained in the wide concentration range from 1.0 × 10 −6 to 1.6 × 10 −3 M. The biosensor was successfully applied to determine the glucose concentration in human serum samples.

Studies on 2D hybrid films of half surfactant-covered Au nanoparticles at the air/water interface

A hybrid monolayer film of Au nanoparticles, half-covered with dioctadecyldimethylammonium chloride (DODAC), was prepared at the air/water interface and characterized using transmission electron microscopy (TEM), a quartz-crystal microbalance, and infrared spectra measurements. TEM images of the hybrid film showed that the distribution of Au nanoparticles depends on the surface density of DODAC and reaction time. IR spectral data provided evidence for a surface-enhanced effect of the Au nanoparticles. The wavenumber of CH 2-stretch vibrations of DODAC in the infrared external reflection spectra revealed that the DODAC molecules were adsorbed onto the Au nanoparticles in a close-packed crystalline state for any surface density of DODAC, which is different from the usual behavior of Langmuir monolayers.

Morphology and properties of poly[2‐methoxy‐5‐(2′‐ethyl‐hexyloxy)‐para‐phenylene vinylene]/silica nanoparticle hybrid films

AbstractPoly[2‐methoxy‐5‐(2′‐ethyl‐hexyloxy)‐para‐phenylene vinylene] (MEH‐PPV)/silica nanoparticle hybrid films were prepared and characterised. Three kinds of materials were compared: parent MEH‐PPV, MEH‐PPV/silica (hybrid A films), and MEH‐PPV/coupling agent MSMA/silica (hybrid B films), in which MSMA is 3‐(trimethoxysilyl) propyl methacrylate. It was found that the hybrid B films could significantly prevent macrophase separation, as evidenced by scanning electron and fluorescence microscopy. Furthermore, the thermal characteristics of the hybrid films were largely improved in comparison with the parent MEH‐PPV. The UV‐visible absorption spectra suggested that the incorporation of MSMA‐modified silica into MEH‐PPV could confine the polymer chain between nanoparticles and thus increase the conjugation length. The photoluminescence (PL) studies also indicated enhancement of the PL intensity and quantum efficiency by incorporating just 2 wt% of MSMA‐modified silica into MEH‐PPV. However, hybrid A films did not show such enhancement of optoelectronic properties as the hybrid B films. The present study suggests the importance of the interface between the luminescent organic polymers and the inorganic silica on morphology and optoelectronic properties. Copyright © 2004 Society of Chemical Industry

Nanostructured Electrochemical Sensor Based on Dense Gold Nanoparticle Films

Polyelectrolyte (PE)/gold nanoparticle hybrid films that can be utilized as efficient electrochemical sensors were prepared by infiltrating 4-(dimethylamino)pyridine-stabilized gold nanoparticles (DMAP−AuNP) into PE multilayers preassembled on indium tin oxide (ITO) electrodes. Quartz crystal microgravimetry (QCM) and UV−vis spectroscopy showed that via this infiltration method, composite films with densely packed DMAP−AuNP were obtained. Electrochemical experiments revealed that the presence of gold nanoparticles in the PE multilayers could significantly improve the electron-transfer characteristics of the films, which showed high electrocatalytic activity to the oxidation of nitric oxide (NO). The sensitivity of the composite films for measuring NO could be further tailored by controlling the gold nanoparticle loading in the film.

A New Approach to the Fabrication of a Self-Organizing Film of Heterostructured Polymer/Cu2S Nanoparticles

The fabrication of polymer/Cu2S nanoparticle hybrid films is described, in which metal–ligand interactions are used to self-organize Cu2+-neutralized polyelectrolytes and pyridine-containing polymers into alternately deposited multilayers, as illustrated in the Figure, where the circles represent the copper salt and the polygons the pyridine moiety.