Size-controlled growth and antibacterial mechanism for Cu:C nanocomposite thin films

This paper aims at developing numerically validated models for predicting the through-plane effective index of refraction and absorption index of nanocomposite thin-films. First, models for the effective optical properties are derived from previously reported analysis applying the volume averaging theory (VAT) to the Maxwell's equations. The transmittance and reflectance of nanoporous thin-films are computed by solving the Maxwell's equations and the associated boundary conditions at all interfaces using finite element methods. The effective optical properties of the films are retrieved by minimizing the root mean square of the relative errors between the computed and theoretical transmittance and reflectance. Nanoporous thin-films made of SiO2 and TiO2 consisting of cylindrical nanopores and nanowires are investigated for different diameters and various porosities. Similarly, electromagnetic wave transport through dielectric medium with embedded metallic nanowires are simulated. Numerical results are compared with predictions from widely used effective property models including (1) Maxwell-Garnett Theory, (2) Bruggeman effective medium approximation, (3) parallel, (4) series, (5) Lorentz-Lorenz, and (6) VAT models. Very good agreement is found with the VAT model for both the effective index of refraction and absorption index. Finally, the effect of volume fraction on the effective complex index of refraction predicted by the VAT model is discussed. For certain values of wavelengths and volume fractions, the effective index of refraction or absorption index of the composite material can be smaller than that of both the continuous and dispersed phases. These results indicate guidelines for designing nanocomposite optical materials.

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Effect of low fluence radiation on nanocomposite thin films of Cu nanoparticles embedded in fullerene C 60

Vacuum ◽

10.1016/j.vacuum.2017.04.034 ◽

2017 ◽

Vol 142 ◽

pp. 5-12 ◽

Cited By ~ 17

Author(s):

Heena Inani ◽

Rahul Singhal ◽

Pooja Sharma ◽

Ritu Vishnoi ◽

S. Aggarwal ◽

...

Keyword(s):

Thin Films ◽

Cu Nanoparticles ◽

Nanocomposite Thin Films

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Dissolution of Cu nanoparticles and antibacterial behaviors of TaN–Cu nanocomposite thin films

Thin Solid Films ◽

10.1016/j.tsf.2009.03.109 ◽

2009 ◽

Vol 517 (17) ◽

pp. 4956-4960 ◽

Cited By ~ 37

Author(s):

P.C. Liu ◽

J.H. Hsieh ◽

C. Li ◽

Y.K. Chang ◽

C.C. Yang

Keyword(s):

Thin Films ◽

Cu Nanoparticles ◽

Nanocomposite Thin Films

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Titanium–vanadium oxide nanocomposite thin films: Synthesis, characterization and antibacterial activity

Materials Chemistry and Physics ◽

10.1016/j.matchemphys.2014.01.035 ◽

2014 ◽

Vol 144 (3) ◽

pp. 538-546 ◽

Cited By ~ 8

Author(s):

A.W. Wren ◽

B.M. Adams ◽

D. Pradhan ◽

M.R. Towler ◽

N.P. Mellott

Keyword(s):

Thin Films ◽

Antibacterial Activity ◽

Vanadium Oxide ◽

Nanocomposite Thin Films ◽

Titanium Vanadium

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Nanomechanical Properties of UV Degraded TiO2/Epoxy Nanocomposites

MRS Proceedings ◽

10.1557/proc-841-r5.10 ◽

2004 ◽

Vol 841 ◽

Cited By ~ 1

Author(s):

Stephanie Scierka ◽

Peter L. Drzal ◽

Amanda L. Forster ◽

Stephanie Svetlik

Keyword(s):

Thin Films ◽

Volume Fraction ◽

Surface Region ◽

Chemical Oxidation ◽

Nanocomposite Films ◽

Attenuated Total Reflectance ◽

Integrating Sphere ◽

Scanning Calorimetry ◽

Nanocomposite Thin Films ◽

Instrumental Indentation

ABSTRACTModel epoxy nanocomposite thin films containing one of three types of titanium dioxide (TiO2) particles were degraded using an integrating sphere-based ultraviolet weathering chamber. Instrumental Indentation Testing (IIT) was used to measure nanomechanical changes in the surface region of thin films resulting from UV exposure. Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR) and Differential Scanning Calorimetry (DSC) were used to support the mechanical results with chemical and thermal data. The unfilled epoxy was the most photosensitive sample tested, exhibiting the highest rates of chemical oxidation, the largest decrease in the glass transition (Tg), and the greatest increase in elastic modulus with increased exposure. Similar trends were observed in the nanocomposite films, but the rates of change were much lower than the unfilled epoxy and decreased with increasing volume fraction of nanoparticles.

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PANI-Ag-Cu Nanocomposite Thin Films Based Impedimetric Microbial Sensor for Detection ofE. coliBacteria

Journal of Nanomaterials ◽

10.1155/2014/951640 ◽

2014 ◽

Vol 2014 ◽

pp. 1-8 ◽

Cited By ~ 2

Author(s):

Huda Abdullah ◽

Norshafadzila Mohammad Naim ◽

Noor Azwen Noor Azmy ◽

Aidil Abdul Hamid

Keyword(s):

Thin Films ◽

Electrochemical Impedance ◽

Oxidative Polymerization ◽

Face Centered Cubic ◽

Cu Nanoparticles ◽

Visible Spectroscopy ◽

High Concentration ◽

E Coli ◽

Nanocomposite Thin Films ◽

Uv Visible

PANI-Ag-Cu nanocomposite thin films were prepared by sol-gel method and deposited on the glass substrate using spin coating technique. Polyaniline was synthesized by chemical oxidative polymerization of aniline monomer in the presence of nitric acid. The films were characterized using XRD, FTIR, and UV-Visible spectroscopy. The performance of the sensor was conducted using electrochemical impedance spectroscopy to obtain the change in impedance of the sensor film before and after incubation withE. colibacteria in water. The peaks in XRD pattern confirm the presence of Ag and Cu nanoparticles in face-centered cubic structure. FTIR analysis shows the stretching of N–H in the polyaniline structure. The absorption band from UV-Visible spectroscopy shows high peaks between 400 nm and 500 nm which indicate the presence of Ag and Cu nanoparticles, respectively. Impedance analysis indicates that the change in impedance of the films decreases with the presence ofE. coli. The sensitivity onE. coliincreases for the sample with high concentration of Cu.

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Nurturing Plasmonic Properties of Nanocomposite Thin Films: The Importance of Optimum Oblate Shape

Journal of Materials and Applications ◽

10.32732/jma.2021.10.2.73 ◽

2021 ◽

Vol 10 (2) ◽

pp. 73-82

Author(s):

Ranjit Laha

Keyword(s):

Thin Films ◽

Volume Fraction ◽

Resonance Condition ◽

Positive Root ◽

Quadratic Equation ◽

Oblate Shape ◽

Nanocomposite Thin Films ◽

Lower Volume ◽

Visible Wavelengths ◽

First Time

Metal nanoparticles (MNPs) embedded dielectric thin films are very crucial for many optoelectronic applications. This report investigates various ways of tuning the plasmonic properties of such nanocomposite thin films. For this, the well-known plasmon resonance condition was first generalized to include the shape and volume fraction of MNPs. This was followed by deriving an empirical formula for the resonance position (λR) which was worked out to be the positive root of a quadratic equation. The coefficients of the deduced quadratic relation involve the parameters obtained from the empirical fit to some of the experimental dielectric functions of MNPs available in literature. The derived working formula enables research community to tune the LSPR of nanocomposites in the whole range of visible wavelengths. The derived formula also concluded that with known lower volume fractions, shape of MNPs affects λR the most, compared to the other parameters. The derived formula was validated by calculating the full extinction spectra. It was shown for the first time that there exists an optimum value of oblate shape to give maximum resonance for a given nanocomposite.

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The Effect of Nanoparticles on the Thermal Conductivity of Crystalline Thin Films at Low Temperatures

Volume 11: Micro and Nano Systems, Parts A and B ◽

10.1115/imece2007-43466 ◽

2007 ◽

Author(s):

Kamal M. Katika ◽

Laurent Pilon

Keyword(s):

Thin Films ◽

Thermal Conductivity ◽

Radiative Transfer ◽

Film Thickness ◽

Volume Fraction ◽

Phonon Transport ◽

Solid Matrix ◽

Discrete Ordinates ◽

Nanoparticle Radius ◽

Nanocomposite Thin Films

This study is concerned with the prediction of the effective thermal conductivity of nanocomposite thin films consisting of nanoparticles randomly distributed in a solid matrix. Crystalline sodium chloride with embedded monodisperse silver nanoparticles is investigated as a case study for thin films where phonons are the main heat carriers. To the best of our knowledge, the equation for phonon radiative transfer is solved for the first time with an exact scattering transport cross-section of the nanoparticles as a function of frequency which was obtained from the literature. The one-dimensional equation for phonon radiative transfer based on the isotropic scaling approximation is solved on a spectral basis using the discrete ordinates method to predict the temperature profile and the heat flux across the nanocomposite thin films. The thermal conductivity is retrieved at temperatures where the effects of Umklapp and Normal processes can be neglected and scattering by the particles on phonon transport dominates. The method of solution and closure laws were validated with experimental data of thermal conductivity for bulk samples at 2.53, 5.94, and 10.56 K. The effects of the film thickness (1 μm to 2.5 cm), nanoparticle diameter (5 nm to 100 nm) and volume fraction (0.0001 to 0.2) on the thermal conductivity of the nanocomposite thin film are investigated. The results indicate that the thermal conductivity decreases with decreasing particle radius as well as with increasing particle concentration. Finally, a dimensionless analysis revealed a power law relationship between the dimensionless thermal conductivity and a dimensionless length of the order of the acoustic thickness of the medium. These results can be used to design nanocomposite thin films for various low temperature thermal applications by choosing optimal nanoparticle radius and volume fraction, and film thickness.

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High performance polymer/BaTiO3 nanocomposites based on surface-modified metal oxide nanoparticles using functional phosphonic acids for electronic applications

MRS Proceedings ◽

10.1557/proc-1113-f02-05 ◽

2008 ◽

Vol 1113 ◽

Author(s):

Philseok Kim ◽

Natalie M. Doss ◽

John P. Tillotson ◽

Xiao-Hong Zhang ◽

Simon C. Jones ◽

...

Keyword(s):

Thin Films ◽

Surface Modification ◽

Metal Oxide ◽

Phosphonic Acid ◽

Volume Fraction ◽

Metal Oxide Nanoparticles ◽

Dielectric Strength ◽

Oxide Nanoparticles ◽

High Quality ◽

Nanocomposite Thin Films

ABSTRACTPolymer/ceramic nanocomposites provide a means of combining the high permittivities (εr) of metal oxide nanoparticles with the solution-processability and high dielectric strength of polymeric hosts. Simple mixing of nanoparticles and polymers generally results in poor quality nanocomposites due to the agglomeration of nanoparticles and poor miscibility of nanoparticles with host materials. We have shown that surface modification of metal oxide nanoparticles with phosphonic acid-based ligands affords robust surface modification and improves the processiblity and the quality of the resulting nanocomposites. We report on the use of phosphonic-acid modified barium titanate (BaTiO3, BT) nanoparticles in dielectric nanocomposites and their applications to high-energy-density capacitors and solution-processable high permittivity gate insulators in organic field-effect transistors (OFETs). Surface modification of BT nanoparticles enabled the formation of high quality nanocomposite thin films with ferroelectric polymer hosts such as poly(vinylidene fluoride-co-hexafluoropropylene), P(VDF-HFP), with large volume fractions (up to 50 vol. %), which are potentially useful materials for electrical energy storage. Similarly, the use of phosphonic acid-modified BT nanoparticles in cross-linked poly(4-vinylphenol) (PVP) allowed to form gate insulators for OFETs. High quality nanocomposite thin films at high nanoparticle volume fractions (up to 37 vol. %) with a large capacitance density (∼50 nF/cm2) and a low leakage current (10−8 A/cm2) were obtained. Pentacene-based p-type OFETs using these nanocomposites showed a large on/off current ratio (Ion/off 104 ∼ 106). We will also present the results from a recent experimental and theoretical study where the BT nanoparticle volume fraction was systematically varied in P(VDF-HFP) host, εr = 11, to find the optimum permittivity and dielectric strength, which provided a guideline for the optimization of the volume fraction for achieving maximum energy density.

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