Poly Ethylene Oxide Nanocomposites Research Articles

Synthesis and Characterization of Rare Earth Doped Ferrite / Polyethylene Oxide Nanocomposites

Nano-sized Li0.5Ni0.48Tb0.02Dy0.1Fe1.9O4 spinel ferrite nanoparticles were synthesized employing the micro-emulsion synthesis method. Polyethylene oxide was prepared through in-situ polymerization route. The ferrite-polymer nanocomposites have been synthesized by combining Li0.5Ni0.48Tb0.02Dy0.1Fe1.9O4 ferrite with polyethylene oxide polymer. Spectral, structural, morphological, and dielectric properties of the prepared nano-ferrite powders as well as nanocomposites were investigated by “X-ray diffraction analysis” (XRD), “scanning electron microscopy” (SEM), “Fourier transform infrared spectroscopy” (FTIR) and dielectric measurements. XRD analysis confirmed the synthesis of single-phase spinel structure only. The dielectric parameter was augmented with an increase of ferrite amount. FTIR spectra confirmed the existence of interactions between polyethylene oxide and ferrite particles. SEM study revealed that the nanocomposites comprised core/shell structure and inhomogeneous distribution of grain size. The dielectric parameters such as “real part of dielectric constant” (?), “imaginary part of dielectric constant” (?"), “tan loss”, “AC conductivity” and “quality factor” were investigated in the required range of frequency; that is, 1 MHz – 3 GHz. The peaking behavior has been observed for real (??) and “imaginary (???) parts of dielectric constant” and “dielectric loss” (tan?). “The peaking behavior” was detected beyond 1.5 GHz. A decrease in “the dielectric constants” and “dielectric loss” was found to with the increasing frequency. Dielectric parameters have been well elucidated by explaining “Debye-type relaxation model” in agreement with two layer “Koop's phenomenological theory”. The present investigated samples might have potential applications in high frequency.

Thermo-responsive behavior of radiation-induced poly(N-isopropylacrylamide)/polyethylene oxide nanocomposite

Temperature-sensitive poly(N-isopropylacrylamide)/polyethylene oxide (PNIPAAm/PEO) nanocomposite hydrogels were successfully synthesized using γ-radiation as the initiator and crosslinking agent. The temperature-dependent swelling and shrinking behavior of PNIPAAm/PEO was exploited in order to form silver nanoparticles within the hydrogel network. Loading-temperature-responsive hybrid microgels containing silver nanoparticles (AgNPs) were readily prepared by the in situ reduction of Ag+ ions within and coordinated to PNIPAAm/PEO hydrogels. A novel method—irradiation—was utilized to generate AgNPs within the previously obtained hydrogel matrix. The newly prepared Ag-NPs/PNIPAAm/PEO hydrogels exhibited much better temperature-sensitive properties than conventional polymers. The PNIPAAm hydrogels thus prepared exhibited properties such as pore size, equilibrium swelling ratio, and swelling/deswelling rates that could be varied by modifying the feed weight ratio of NIPAAm to PEO. UV-Vis spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), and energy-dispersive X-ray (EDX) measurements confirmed that the hydrogel possessed nanostructure, and FTIR was employed to characterize the components of the resulting nanoobjects. The hydrodynamic diameter and morphology of the microgel particles were examined by dynamic light scattering (DLS) and scanning electron microscopy (SEM), respectively. At room temperature, the hydrodynamic diameter of the PNIPAAm/PEO polymer was measured as 3.0 ± 0.7 μm, while that of the PNIPAAm/PEO-stabilized AgNPs was found to be 1.8 ± 0.1 μm. Twenty-five percent of the silver nanoparticles were less than 64.9 nm in diameter, and the mean of the particle size was 9.6 nm. These stimuli-responsive nanocomposite hydrogels have potential applications in biomedicine; for example, they could be used as drug-delivery matrices.

Rheology and Microstructure of Polymer Nanocomposite Melts: Variation of Polymer Segment−Surface Interaction

We have studied the effects of particle packing fraction, polymer molecular weight (MW), and polymer-segment-particle-surface affinity on the phase behavior of 44 nm silica dispersions in unentangled, low MW polyethylene oxide (PEO), polyethylene oxide dimethyl ether (PEODME), and polytetrahydrofuran (PTHF) through rheological measurement and small-angle X-ray scattering. Particles are shown to be stable in PEO nanocomposites up to high volume fractions due to an adsorbed layer of polymer segments that stabilizes particles in the melt. Comparison of the PEO nanocomposite to PEODME and PTHF nanocomposites reveals little evidence of an adsorbed layer in the spirit of the PEO nanocomposite. Measurement of the PTHF nanocomposite viscosity reveals evidence of segment slip at the particle surface by the particle intrinsic viscosity being less than Einstein's value. At higher particle volume fractions, the viscosity diverges, yielding an elastic response. The elastic response of the PEO nanocomposite has the signatures of a colloidal glass, while the PEODME and PTHF nanocomposites resemble a gel. Measurement of the particle structure factor reveals a change from overall repulsive particles in PEO to attractive particles in PTHF as the segment-surface interaction is changed.

Magnetron sputtering synthesis silver and organic PEO nanocomposite

A nanocomposite, silver nanoparticles embedded into polyethylene oxide (PEO) is synthesized by magnetron sputtering. The embedded silver in PEO matrix is confirmed by transmission electron microscopy (TEM) image, X-ray diffraction (XRD) pattern, and atomic force microscopy (AFM) analysis. By TEM image the sizes of silver nanoparticles are found to be tunable, and the silver crystallization is preferentially grown in facet of (111) by varying the plasma parameters, especially the working pressure. The crystal statue is evidenced by UV–visible spectra where the peak of plasmon absorption is located at ca. 400 nm. This characterization is very important for silver nanocomposite application as an antibacterial reagent based on previous antimicrobial results. By Fourier transform infrared spectroscopy (FTIR) the functional group of C–O–C in PEO films is depicted to be enough retained from the monomer in MS plasma.

Preferential Facet of Nanocrystalline Silver Embedded in Polyethylene Oxide Nanocomposite and Its Antibiotic Behaviors

In this article, a magnetron sputtering (MS) method is reported to prepare a nanocomposite of embedded silver nanoparticles in simultaneously polymerized, nonfouling polyethylene oxide (PEO) film. ...