Polymer-inorganic Nanocomposites Research Articles

Facile Preparation of Polysarcosine-Tethered Inorganic Nanospheres by Using Unimolecular Polypept(o)ides as Template.

Polymer-inorganic nanocomposites that integrate the advantages of both polymers and inorganic nanoparticles (NPs) are broadly exploited for versatile applications. Especially, emerging polymer-templated preparation of inorganic NPs has drawn extensive attention, which is ascribed to simplified synthesis and feasible tunability. However, how to precisely fabricate biocompatible polymer-inorganic NPs remains unsolved. In this article, by mild ring opening polymerization (ROP) of β-benzyl L-aspartate N-carboxyanhydrides (BLA-NCAs) and sarcosine N-carboxyanhydrides (Sar-NCAs) and subsequent debenzylation, a series of poly(amino acid)-based unimolecular micelles (PAMAM-g-(PLA-b-PSar)) are facilely synthesized. Afterward, by utilization of these star-like polymers as template, the controllable preparation of various PSar-tethered inorganic NPs is investigated and characterized meticulously. This general strategy for the preparation of PSar-tethered inorganic NPs can bring a great chance for future fabrication of biomedical nanoplatforms.

Porous Hybrid PVDF/BiFeO3 Smart Composite with Magnetic, Piezophotocatalytic, and Light-Emission Properties

The creation of multi-stimuli-sensitive composite polymer–inorganic materials is a practical scientific task. The combination of photoactive magneto-piezoelectric nanomaterials and ferroelectric polymers offers new properties that can help solve environmental and energy problems. Using the doctor blade casting method with the thermally induced phase separation (TIPS) technique, we synthesized a hybrid polymer–inorganic nanocomposite porous membrane based on polyvinylidene fluoride (PVDF) and bismuth ferrite (BiFeO3/BFO). We studied the samples using transmission and scanning electron microscopy (TEM/SEM), infrared Fourier spectroscopy (FTIR), total transmission and diffuse reflection, fluorescence microscopy, photoluminescence (PL), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), vibrating-sample magnetometer (VSM), and piezopotential measurements. Our results demonstrate that the addition of BFO increases the proportion of the polar phase from 76.2% to 93.8% due to surface ion–dipole interaction. We also found that the sample exhibits laser-induced fluorescence, with maxima at 475 and 665 nm depending on the presence of nanoparticles in the polymer matrix. Furthermore, our piezo-photocatalytic experiments showed that under the combined actions of ultrasonic treatment and UV–visible light irradiation, the reaction rate increased by factors of 68, 13, 4.2, and 1.6 compared to sonolysis, photolysis, piezocatalysis, and photocatalysis, respectively. This behavior is explained by the piezoelectric potential and the narrowing of the band gap of the composite due to the mechanical stress caused by ultrasound.

Polyaniline/ZnO Hybrid Nanocomposite: Morphology, Spectroscopy and Optimization of ZnO Concentration for Photovoltaic Applications

The appropriate combination of semiconducting polymer-inorganic nanocomposites can enhance the existing performance of polymers-only-based photovoltaic devices. Hence, polyaniline (PANI)/zinc oxide (ZnO) nanocomposites were prepared by combining ZnO nanoparticles with PANI in four distinct ratios to optimize their photovoltaic performance. Using a simple coating method, PANI, ZnO, and its nanocomposite, with varying weight percent (wt%) concentrations of ZnO nanoparticles, i.e., (1 wt%, 2 wt%, 3 wt%, and 4 wt%), were fabricated and utilized as an active layer to evaluate the potential for the high-power conversion efficiency of various concentrations, respectively. PANI/ZnO nanocomposites are characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), atomic force microscopy (AFM), Fourier transform infrared (FTIR) spectroscopy, ultraviolet-visible (UV-vis) absorption, energy dispersive X-ray (EDX), and I-V measurement techniques. The XRD analysis showed a distinct, narrow peak, which corresponds to the wurtzite ZnO (101) plane. The SEM analysis verified the production of the PANI/ZnO composite by demonstrating that the crystalline ZnO was integrated into the PANI matrix. The elemental composition was determined by energy dispersive X-ray analysis (EDX), which confirmed the existence of PANI and ZnO without any impurities, respectively. Using Fourier transform infrared (FTIR) spectroscopy, various chemical bonds and stretching vibrations were analyzed and assigned to different peaks. The bandgap narrowing with an increasing PANI/ZnO composition led to exceptional optical improvement. The I-V characterization was utilized to investigate the impact of the nanocomposite on the electrical properties of the PANI/ZnO, and various concentrations of ZnO (1 wt%, 2 wt%, 3 wt%, and 4 wt%) in the PANI matrix were analyzed under both light and dark conditions at an STC of 1.5 AM globally. A high PCE of 4.48% was achieved for the PANI/ZnO (3 wt%), which revealed that the conductivity of the PANI/ZnO nanocomposite thin films improved with the increasing nanocomposite concentration.

Dual-modal biosensor for highly sensitive and selective DNA methyltransferase activity detection based on a porous organic polymer-inorganic nanocomposite (Cu2O@FePPOPBADE) with high laccase-like activity

Abnormal DNA Methyltransferase (MTase) activity is closely related with multiple human diseases, which triggered its accurate and sensitive detecting demands. Here, an electrochemical and colorimetric, dual-modal biosensor for Dam MTase (Dam) assay was developed based on an organic-inorganic nanocomposite (Cu2O@FePPOPBADE). Stemming from the laccase-like activity of Cu2O, the catalytic activity of ferriporphyrin and excellent protective effect of the FePPOPBADE shell, Cu2O@FePPOPBADE not only exhibited significantly improved laccase-like activity to catalyze the chromogenic reaction of 2,4-dichlorophenol (2,4-DP) with 4-aminoantipyrine (4-AP), but possessed a strong electrochemical signal. Cu2O@FePPOPBADE was further functionalize with Au nanoparticles and served as a signal probe (Cu2O@FePPOPBADE@AuNPs). Also, magnetic bead (MB)/dsDNA was designed by assembly of streptavidin-modified MB with biotinylated-terminated ssDNA1 and thiolated-terminated ssDNA2, both of which contained specific sequences 5′-G-A-T-C-3′. When Dam and Dpn I were present, the specific sequence of dsDNA is methylated by Dam and then is cut by Dpn I, causing the leaving of thiolated-terminated ssDNA2. Sequentially, the residual MB/dsDNA is linked to the Cu2O@FePPOPBADE@AuNPs probe via Au-S bonds. After another magnetic separation, the unlinked Cu2O@FePPOPBADE@AuNPs left in the supernatant were transferred to accomplish the “dual signal-on” analysis of Dam with lower detection limits and high specificity.

Spectroelectrochemistry of Electroactive Polymer Composite Materials.

In this review, we have summarized the main advantages of the method of spectroelectrochemistry as applied to recent studies on electrosynthesis and redox processes of electroactive polymer composite materials, which have found wide application in designing organic optoelectronic devices, batteries and sensors. These polymer composites include electroactive polymer complexes with large unmovable dopant anions such as polymer electrolytes, organic dyes, cyclodextrins, poly(β-hydroxyethers), as well as polymer-inorganic nanocomposites. The spectroelectrochemical methods reviewed include in situ electron absorption, Raman, infrared and electron spin resonance spectroscopies.

Engineering Antimicrobial Polymer Nanocomposites: In Situ Synthesis, Disruption of Polymicrobial Biofilms, and In Vivo Activity.

The increasing incidence of microbial infections and a limited arsenal of effective antibacterial and antifungal agents have entailed the need for new broad-spectrum therapeutics. Polymer-inorganic nanocomposites have emerged as an integral choice of antimicrobials but are limited by complicated synthesis, narrow-spectrum activity, and poor in vivo efficacy. Herein, chloride counterions of a nontoxic, moderately antibacterial polymer have been explored for in situ nanoprecipitation-based synthesis of water-soluble polymer-silver chloride nanocomposites. With the controlled release of silver ions, the nanocomposites were highly active against multidrug-resistant bacteria as well as fluconazole-resistant fungi. Alongside the elimination of metabolically inactive bacterial cells, the nanocomposites disrupted polymicrobial biofilms, unlike antibiotics and only silver-based ointments. This underlined the role of the engineered composite design, where the polymer interacted with the biofilm matrix, facilitating the penetration of nanoparticles to kill microbes. Further, the nanocomposite diminished Pseudomonas aeruginosa burden in mice skin infection (>99.9%) with no dermal toxicity proving its potential for clinical translation.

Cuprous Oxide Nanoparticles: Synthesis, Characterization, and Their Application for Enhancing the Humidity-Sensing Properties of Poly(dioctylfluorene).

In this paper, we report on the synthesis—via the wet chemical precipitation route method—and thin film characteristics of inorganic semiconductor, cuprous oxide (Cu2O) nanoparticles, for their potential application in enhancing the humidity-sensing properties of semiconducting polymer poly(9,9-dioctylfluorene) (F8). For morphological analysis of the synthesized Cu2O nanoparticles, transmission electron microscope (TEM) and scanning electron microscope (SEM) micrographs are studied to investigate the texture, distribution, shape, and sizes of Cu2O crystallites. The TEM image of the Cu2O nanoparticles exhibits somewhat non-uniform distribution with almost uniform shape and size having an average particle size of ≈24 ± 2 nm. Fourier transformed infrared (FTIR) and X-ray diffraction (XRD) spectra are studied to validate the formation of Cu2O nanoparticles. Additionally, atomic force microscopy (AFM) is performed to analyze the surface morphology of polymer-inorganic (F8-Cu2O) nanocomposites thin film to see the grain sizes, mosaics, and average surface roughness. In order to study the enhancement in sensing properties of F8, a hybrid organic–inorganic (F8-Cu2O) surface-type humidity sensor Ag/F8-Cu2O/Ag is fabricated by employing F8 polymer as an active matrix layer and Cu2O nanoparticles as a dopant. The Ag/F8-Cu2O/Ag device is prepared by spin coating a 10:1 wt% solution of F8-Cu2O nanocomposite on pre-patterned silver (Ag) electrodes on glass. The inter-electrode gap (≈5 μm) between Ag is developed by photolithography. To study humidity sensing, the Ag/F8-Cu2O/Ag device is characterized by measuring its capacitance (C) as a function of relative humidity (%RH) at two different frequencies (120 Hz and 1 kHz). The device exhibits a broad humidity sensing range (27–86%RH) with shorter response time and recovery time, i.e., 9 s and 8 s, respectively. The present results show significant enhancement in the humidity-sensing properties as compared to our previously reported results of Ag/F8/Ag sensor wherein the humidity sensing range was 45–78%RH with 15 s and 7 s response and recovery times, respectively. The improvement in the humidity-sensing properties is attributed to the potential use of Cu2O nanoparticles, which change the hydrophobicity, surface to volume ratio of Cu2O nanoparticles, as well as modification in electron polarizability and polarity of the F8 matrix layer.

Nanocomposites based on thermoplastic aromatic polyimides with cerium dioxide nanoparticles: dielectric spectroscopy

The molecular mobility of films of thermoplastic aromatic polyimides and nanocomposites based on them with 3% cerium dioxide has been studied by dielectric spectroscopy. Three relaxation regions of dipole polarization were found for the initial polyimides, γ and β (in the glassy state) and α (transition to a highly elastic state).The introduction of 3% cerium dioxide into the matrix polyimide leads to the suppression of the γ process and to the appearance in the spectra of nanocomposites, along with the β process, of the second relaxation process β1.The temperature dependences of the relaxation time for the γ, β and β1 processes are linear and correspond to the Arrhenius equation, and for the α process are curved and described by the Vogel-Tamman-Hesse equation. The interpretation of the molecular mechanisms of the observed processes is given. Keywords: Polymer-inorganic nanocomposites, aromatic polyimides, nanoscale cerium dioxide, dielectric characteristics, transition temperatures, molecular mechanisms of dielectric processes.

Dual-Modal Biosensor for Highly Sensitive and Selective DNA Methyltransferase Activity Detection Based on a Porous Organic Polymer-Inorganic Nanocomposite (Cu2o@Feppopbade) with High Laccase-Like Activity

Dual-Modal Biosensor for Highly Sensitive and Selective DNA Methyltransferase Activity Detection Based on a Porous Organic Polymer-Inorganic Nanocomposite (Cu2o@Feppopbade) with High Laccase-Like Activity

Multifunctional poly(vinylidene fluoride) and styrene butadiene rubber blend magneto-responsive nanocomposites based on hybrid graphene oxide and Fe3O4: synthesis, preparation and characterization

Two materials were used, like graphene oxide nanosheets (GOn) and ferromagnetic nanoparticles (Fe3O4), to attenuate the electromagnetic (EM) properties in blend hybrid nanocomposites based on styrene-butadiene rubber (SBR) and polyvinylidene difluoride (PVDF) as the matrix. The rationale behind using either a ferroelectric or a ferromagnetic nanofillers as Fe3O4 in combination with intrinsically conducting nanofillers (graphene oxide) at different weight ratios (3.75:1.25; 2.5:2.5 and 1.25:3.75), is to induce both electrical and magnetic dipoles in the hybrid nanocomposite system and characterization to determine the effect of nanofillers hybridization in improving the structural, mechanical, dielectric/electrical, magnetic and thermal properties of a polymer blend (PVDF-SBR) for electromagnetic interference (EMI) shielding application. Due to the synergy between both nanofillers, it was found that Young’s modulus of the nanocomposite containing 5 wt% of the hybrid nanofiller was significantly improved (87%), while the strain at yield remained constant due to the low particle content and the rubbery effect of the SBR copolymer. In addition, the degradation temperature of the matrix was shifted from 464 to 472 °C with the addition of 2.5:2.5 of GOn:Fe3O4. Finally, the hybrid reinforcement also had a positive effect on the electrical and magnetic properties of the nanocomposites with an improvement that exceeds 30%. By careful selection of synthetic techniques and understanding/exploiting the unique physics of the polymeric nanocomposites in such materials, novel functional polymer-inorganic nanocomposites can be designed and fabricated for new interests in magneto applications such as superparamagnetism, electromagnetic wave absorption, and electromagnetic interference shielding. This study opens new avenues to design flexible and lightweight electromagnetic interference shielding materials by careful selection of functional nanoparticles.

Synchronously Strengthen and Toughen Polypropylene Using Tartaric Acid-Modified Nano-CaCO3.

In order to overcome the challenge of synchronously strengthening and toughening polypropylene (PP) with a low-cost and environmental technology, CaCO3 (CC) nanoparticles are modified by tartaric acid (TA), a kind of food-grade complexing agent, and used as nanofillers for the first time. The evaluation of mechanical performance showed that, with 20 wt.% TA-modified CC (TAMCC), the impact toughness and tensile strength of TAMCC/PP were 120% and 14% more than those of neat PP, respectively. Even with 50 wt.% TAMCC, the impact toughness and tensile strength of TAMCC/PP were still superior to those of neat PP, which is attributable to the improved compatibility and dispersion of TAMCC in a PP matrix, and the better fluidity of TAMCC/PP nanocomposite. The strengthening and toughening mechanism of TAMCC for PP involves interfacial debonding between nanofillers and PP, and the decreased crystallinity of PP, but without the formation of β-PP. This article presents a new applicable method to modify CC inorganic fillers with a green modifier and promote their dispersion in PP. The obtained PP nanocomposite simultaneously achieved enhanced mechanical strength and impact toughness even with high content of nanofillers, highlighting bright perspective in high-performance, economical, and eco-friendly polymer-inorganic nanocomposites.

A NOVEL ROUTE FOR THE FORMATION OF GAS SENSORS

The rapid development of conductive polymers shows great potential in temperature chemical gas detection as their electrical conductivity is often changed upon spotlight to oxidative or reductive gas molecules at room temperature. However, the relatively low conductivity and high affinity toward volatile organic compounds and water molecules always exhibit low sensitivity, poor stability and gas selectivity, which hinder their practical gas sensor applications. In addition, inorganic sensitive materials show totally different advantages in gas sensors like high sensitivity, fast response to low concentration analytes, high area and versatile surface chemistry, which could harmonize the conducting polymers in terms of the sensing individuality. It seems to be a good option to combine inorganic sensitive materials with polymers for gas detection for the synergistic effects which has attracted extensive interests in gas sensing applications. In this appraisal the recapitulation of recent development in polymer inorganic nanocomposites-based gas sensors. The roles of inorganic nanomaterials in improving the gas sensing performances of conducting polymers are introduced and therefore the progress of conducting polymer inorganic nanocomposites including metal oxides, metal, carbon (carbon nanotube, graphene) and ternary composites are obtainable. Finally, conclusion and perspective within the field of gas sensors incorporating conducting polymer inorganic nanocomposites are summarized. Keywords: Gas sensor, conducting polymer, polymer-inorganic nanocomposites; conducting organic polymers nanostructure, synergistic effect, polypyrrole (PPY), polyaniline (PANI).

Tunable High Refractive Index Polymer Hybrid and Polymer-Inorganic Nanocomposite Coatings.

Atomized spray plasma deposition (ASPD) provides a single-step, low-temperature, and dry approach for the preparation of high refractive index hybrid polymer or polymer–inorganic nanocomposite coatings. Refractive indices as high as 1.936 at 635 nm wavelength have been obtained for ASPD 4-bromostyrene/toluene–TiO2 nanocomposite layers containing low titania loadings. Thin films with any desired refractive index up to 1.936 can be easily deposited onto a variety of substrates by varying the precursor mixture composition. ASPD overcomes disadvantages commonly associated with alternative fabrication methods for depositing high refractive index coatings (elevated temperatures, wet processes, UV curing steps, and much greater inorganic loadings).

The impact of film thickness on the properties of ZnO/PVA nanocomposite film

Polymer inorganic nanocomposites are attracting a considerable amount of interest due to their enhanced electrical and optical properties. The inclusion of inorganic nanoparticles into the polymer matrix results in a significant change in the nanocomposite’s properties. With this in mind, we have developed a nanocomposite film based on zinc oxide (ZnO) and polyvinyl alcohol (PVA) using a solution casting method with varying concentrations of ZnO nano powder in the PVA matrix. The ZnO / PVA film surface morphology was observed by the scanning electron microscope (SEM). The micrographs indicate that ZnO nanoparticles in the PVA matrix are homogeneously distributed. XRD results indicated that the crystallinity of the film was influenced by the interaction of ZnO nanoparticles and the PVA main chain. Crystallinity is also affected by the doping of ZnO nanoparticles in the PVA matrix and it increases when the concentration of ZnO is low and then decreases when the excess concentration of ZnO is present in the PVA matrix. The FTIR transmission spectra confirmed that significant interaction took place between the ZnO nanoparticles and the PVA main chain over the wave number range of 400–4000 cm−1. The UV–vis spectra reveal that the increase in concentration of ZnO nanoparticles in the polymer matrix results in the movement of the absorption edge in the direction of higher wavelength or lower energy associated with the blue/green portion of the visible spectrum. A decrease in the optical energy bandgap is observed with the increase in nano ZnO concentration in the matrix. Thickness has a signifcant affect on the properties of the ZnO/PVA nanocomposite and the morphology, particle size, degree of crystallinity and bandgap of the ZnO/PVA nanocomposite samples were influenced by the thickness of the sample. The optimal thickess of 0.03 mm with a weight percentage of 16.6% (ZnO) and 83.3% (PVA matrix) was selected due to its higher bandgap of 4.22 eV, reduced agglomeration/aggregation and smaller ZnO particle size of 14.23 nm in the matrix. The optimal film can be used in photovoltaic research.

Kinetically Controlled Self-Assembly of Binary Polymer-Grafted Nanocrystals into Ordered Superstructures via Solvent Vapor Annealing

Polymer-inorganic nanocomposites based on polymer-grafted nanocrystals (PGNCs) are enabling technologically relevant applications owing to their unique physical, chemical, and mechanical properties. While diverse PGNC superstructures have been realized through evaporation-driven self-assembly, this approach presents multifaceted challenges in experimentally probing and controlling assembly kinetics. Here, we report a kinetically controlled assembly of binary superstructures from a homogeneous disordered PGNC mixture utilizing solvent vapor annealing (SVA). Using a NaZn13-type superstructure as a model system, we demonstrate that varying the solvent vapor pressure during SVA allows for exquisite control of the rate and extent of PGNC assembly, providing access to nearly complete kinetic pathways of binary PGNC crystallization. Characterization of kinetically arrested intermediates reveals that assembly follows a multistep crystallization pathway involving spinodal-like preordering of PGNCs prior to NaZn13 nucleation. Our work opens up new avenues for the synthesis of multicomponent PGNC superstructures exhibiting multifunctionalities and emergent properties through a thorough understanding of kinetic pathways.

Polymer-Inorganic Thermoelectric Nanomaterials: Electrical Properties, Interfacial Chemistry Engineering, and Devices.

Though solar cells are one of the promising technologies to address the energy crisis, this technology is still far from commercialization. Thermoelectric materials offer a novel opportunity to convert energy between thermal and electrical aspects, which show the feasibility to improve the performance of solar cells via heat management and light harvesting. Polymer–inorganic thermoelectric nanocomposites consisting of inorganic nanomaterials and functional organic polymers represent one kind of advanced hybrid nanomaterials with tunable optical and electrical characteristics and fascinating interfacial and surface chemistry. During the past decades, they have attracted extensive research interest due to their diverse composition, easy synthesis, and large surface area. Such advanced nanomaterials not only inherit low thermal conductivity from polymers and high Seebeck coefficient, and high electrical conductivity from inorganic materials, but also benefit from the additional interface between each component. In this review, we provide an overview of interfacial chemistry engineering and electrical feature of various polymer–inorganic thermoelectric hybrid nanomaterials, including synthetic methods, properties, and applications in thermoelectric devices. In addition, the prospect and challenges of polymer–inorganic nanocomposites are discussed in the field of thermoelectric energy.

Synthesis and characterization of polypyrrole-Ce0.05CoSb3 nanocomposites

Filled Skutterudite CeyCoSb3 (y = 0.05) nanoparticles synthesized by Solvothermal method are incorporated into conducting Polypyrrole (PPy) via in-situ Chemical Polymerization technique to form Polymer Inorganic Nanocomposites (PINs). Further, studies on different weight percent (10, 20, 30 and 40%) of the nanocomposites with respect to pure PPy are conducted. Field Emission Scanning Electron Microscopy (FESEM) equipped with Energy Dispersive X-Ray Spectrometer (EDS), powder X-Ray Diffractometer (pXRD), Fourier Transform Infrared (FTIR) Spectroscopy techniques were employed to study morphological, structural and optical properties of as-synthesized PINs. FESEM confirms uniform distribution of nanoparticles in polymer matrix and increase in atomic weight % of CeyCoSb3 (y = 0.05) shown in EDS analysis confirms the successful fusing of nanoparticles into the PPy chains. pXRD analysis justifies the formation of PPy-Ce0.05CoSb3 nanocomposites indicating the presence of Ce0.05CoSb3 diffraction peaks with broad amorphous background of polypyrrole. FTIR spectra reveal the vibrational modes and the chemical bonds of pure PPy and PPy fused with Ce0.05CoSb3 justifying the formation of expected nanocomposites.

Preparation of polyacrylamide/nanosheets LYH:Eu nanocomposite film and enhanced photoluminescence

Abstract The Polymer/inorganic nanocomposite (PNC) film of HTTA modified layered rare-earth hydroxide nanosheets cross-linked polyacrylamide (HTTA-LYH:Eu-PAM) was successfully synthesized. Because of the antenna effect between the ligand and luminescence center, the ultra-thin LYH:Eu nanosheets revealed highly photoluminescence property after modified by HTTA. The HTTA-LYH:Eu-PAM composite film prepared by spin coating method exhibited high light transmittance, and high quantum efficiency.

Crystal structures and magnetic properties of polyethylene glycol/polyacrylamide encapsulated CoCuFe4O8 ferrite nanoparticles

Polymer-inorganic nanocomposites with systematized structure provide a novel composite material having complementary between the polymer and inorganic materials. A new CoCuFe4O8 spinel ferrite was prepared by a modified citrate auto combustion technique. The formation of the core–shell structure by coating CoCuFe4O8 nanoparticles (NPs) with Polyethylene glycol (PEG) or Polyacrylamide (PAM) was successfully proceeding. The X-ray diffraction analysis shows that the prepared sample crystallizes in a cubic crystal structure with the Fd3m space group. The structural changes are elucidated via diametrical size, lattice parameter, dislocation density and strain. The obtained data reveals that after coating with PEG/PAM the crystallite size of CoCuFe4O8 spinel ferrite nanoparticles decreases while, the dislocation density increases. The dislocation density provides more energy-friendly locations for nucleation, consequently, the crystallinity deteriorates and the crystal grains become finer. High-Resolution Transmission Electron Microscopy (HRTEM) images ratify that the spinel nanoparticles are embedded in the PEG/PAM matrix forming the core–shell structure. The measurements of the magnetic hysteresis loops assure that all prepared samples exhibit a hard ferrite nature with a coercivity ranging from 1525 to 1512 Oe. The decrease of the magnetic parameters of CoCuFe4O8/PEG-PAM can be explained on the basis of the contribution of the non-magnetic coating layer to the total magnetization. The total magnetic behavior of the nanocomposites can be tuned and tailored depending on the coating layers. Based on the obtained data, the formulated CoCuFe4O8 decorated with PEG-PAM can be recognized as a promising functional material for applications in biomedicine. The enhanced magnetic properties make CoCuFe4O8/PEG-PAM a fitting candidate in the high-density recording.

Experimental and Monte Carlo investigations of gamma ray transmission and buildup factors for inorganic nanoparticle/epoxy composites

The integration of inorganic nanoparticles into a polymer matrix presents a category of advanced materials, known as polymer inorganic nanocomposites (PINCs). In present work, the γ-ray shielding parameters of epoxy resin loaded with two different proportions (5 and 25 wt%) of Pb, Zn, ZnO, Ti and TiO2 inorganic nanoparticles have been investigated. The prepared samples were characterized through structural investigations including SEM, EDS, XRD and FT-IR analyses. Furthermore, mechanical properties of the nanocomposites were evaluated on the basis of compressive strength. To evaluate the γ-ray attenuation performance of the nanocomposites, the transmission and flux buildup factors have been measured experimentally. The 59.54 and 662 keV γ-rays emitted from 241Am and 137Cs point sources were counted by a 2″ × 2″ NaI(Tl) detector. In addition, experimental results has been confirmed by a theoretical study using MCNPX code. The results showed that γ-ray shielding effectiveness was enhanced by the increment of the filler loading. The experimental and theoretical calculations of transmission and buildup factors were found to be in a good agreement. As expected, 25 wt% Pb/epoxy nanocomposites indicated better shielding properties than their counterparts. However, it has to be notices that the mechanical strength of Pb/epoxy nanocomposites were determined significantly lower than those of Zn, ZnO, Ti and TiO2/epoxy nanocomposites. To design and choose an appropriate shielding material, therefore, a number of factors have to be considered.