Black Nanoparticles Research Articles

Investigating Gas Promoted Ir Deposition on Pt Black Nanoparticles As Synthesis Method for Bifunctional OER/ORR Catalyst in Acidic Media

A reversible fuel cell (rFC) integrates a fuel cell (FC) and a water electrolyser (WE) into a single energy conversion device. One potential implementation of an rFC involves operating each electrode with a fixed gas. Specifically, the oxygen electrode would carry out the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) depending on the operation mode. However, a major challenge is the development of a bifunctional catalyst for the oxygen electrode, since the faster hydrogen electrode can be operated with Pt as catalyst for both, hydrogen evolution and oxidation reaction (HER/HOR). State-of-the-art catalyst materials in acidic media, such as Pt and Ir for the ORR and OER, respectively, face challenges due to oxidative and reductive potentials during FC and WE mode operation. Ir undergoes multiple oxidation state changes during the transient between FC and WE operation mode, resulting in dissolution of the material [1]. Pt faces similar oxidation mechanisms and possible dissolution in WE mode [2].To address these challenges, we propose a Pt@Ir bifunctional catalyst for rFC applications, where Ir is deposited in a non-continuous monolayer shell on Pt particles to maintain active surface area for both reactions. However, in order to control the synthesis of such a composite catalyst, a basic understanding of Pt-Ir interactions has to be established, which is also of interest to cell reversal mitigation catalysts commonly employed in PEM FC.Herein, we present investigations on Ir deposition on Pt nanoparticles, which builds the foundation for a simple and scalable synthesis method for the proposed Pt@Ir catalyst. We start with investigations on potential-driven deposition of Ir on Pt nanoparticles to study how Ir deposition evolves with applied potential and compare the characteristics with Ir deposition on Ir and Au nanoparticles as reference. We show that Ir deposition on Pt happens at lower cathodic polarization hinting toward a preferential Ir ion reduction on Pt. Further we investigate the hydrogen gas driven deposition of Ir on Pt before transferring the knowledge from a three-electrode set up into a bulk synthesis. The high activity of adsorbed hydrogen gas on Pt surface allows a reduction of metal ions exclusively on Pt surface [3], which seems to be also possible for Ir ions.We present the successful gas-promoted deposition of Ir on Pt black nanoparticles as bifunctional catalyst for OER/ORR in acidic media. Additionally, we demonstrate the full cell performance of this catalyst in PEM WE and PEM FC operation.REFERENCES[1] Geiger, S.; Kasian, O.; Shrestha, B.R.; Mingers, A.M.; Mayrhofer, K.J.J.; Cherevko, S. Activity and Stability of Electrochemically and Thermally Treated Iridium for the Oxygen Evolution Reaction. J. Electrochem. Soc., 2016, 163, F3132-F3138.[2] Sugawara, Y.; Okayasu, T.; Yadav, A.P.; Nishikata, A.; Tsuru, T. Dissolution Mechanism of Platinum in Sulfuric Acid Solution. J. Electrochem. Soc., 2012, 159, F779-F786.[3] Loichet Torres, P.A.; El-Sayed, H.A.; Schwämmlein, J.N.; Friedrich, F.; Gasteiger, H.A. Hydrogen Gas Promoted Self-Limiting Copper Monolayer Deposition on Platinum. J. Electrochem. Soc., 2021, 168, 52508. Figure 1

(Invited) Synthesis of TiO2-Based for Electrocatalysts CO2 Reduction Using in-Liquid Plasma Method and Control of Their Reduction Properties

Introduction In recent years, there has been growing interest in converting carbon dioxide (CO2), a greenhouse gas, into a valuable resource. The electrolytic reduction method, which uses only water and electricity, offers a particularly clean approach to CO2 conversion. Its high conversion efficiency at ambient temperature and pressure, facilitated by gas diffusion electrodes (GDE), makes it a promising option for widespread adoption. Electrocatalytic CO2 reduction using GDE selectively yields carbon monoxide, ethylene, and formic acid with Ag, Cu, or Sn catalysts, respectively 1). These catalysts are often supported on conductive carbon black (CB), valued for its high electrical conductivity and porosity. However, CB-based catalysts encounter challenges like redox-induced degradation and high CO2 overvoltage. So, we turned to plasma in liquid as a new method for making electrocatalysts. Plasma in liquid is generated by subjecting a metal in solution to high-frequency, high-voltage conditions. This process enables the sputtering of metal onto powder samples dispersed in solution, with the metal surface instantly heated to high temperatures. This process can improve electrochemical properties like oxygen deficiency 2). Consequently, plasma treatment in liquid presents an opportunity to utilize highly durable and chemically resistant metal oxides as catalyst base materials. The objective of this study was to synthesize a new catalyst for electrocatalytic CO2 reduction using titanium dioxide as the catalyst base via in-liquid plasma. Titanium dioxide offers advantages of affordability, durability, and chemical resistance. Moreover, oxygen-deficient TiO2 with enhanced conductivity finds application as a base material for batteries.Experimental In the experiments, high-frequency high voltage (4 kV, 100 kHz, 0.5 µs-Pulse Width) was applied under the same conditions to various metal electrodes in a 5.0 wt%-NH4 solution (200 mL) containing dispersed TiO2 (P25: 0.5 g) to generate plasma in the liquid. Common plasma electrodes included tungsten (W), silver (Ag), and copper (Cu). Each gas diffusion electrode (GDE) was prepared by washing the powder after in-liquid plasma treatment with pure water, followed by spray coating on a gas diffusion layer with Nafion dispersion as a binder. Electrocatalytic CO2 reduction was evaluated in a conventional three-chamber gas diffusion cell at 500 mA/cm2 for 10 minutes. The CO2 supplied to the gas chamber was collected in a Tedlar bag, and the CO2 reduction products were analyzed by gas chromatography. Results and Discussion Figure shows the CO2 reduction products and Faraday efficiency of P25 treated with various liquid plasma electrodes. In pristine P25, small amounts of CO and CH4 were detected due to the redox cycle of Ti4+ and Ti3+. The use of tungsten (W), silver (Ag), and copper (Cu) as in-liquid plasma electrodes increased the production of H2, CO, and CH4, respectively. The difference in conversion can be attributed to the fact that the amount of etched Cu is less than that of Ag. Additionally, black nanoparticles were dispersed in the filtered solution when Ag was used, while the solution turned a clear blue color with Cu, suggesting the formation of a complex with ammonia. Generally, oxidized metal nanoparticles are synthesized when plasma is generated in solution. In this study, since an alkaline solution was used, it can be considered that the oxidized Ag nanoparticle surfaces were reduced, resulting in highly dispersed reduced Ag nanoparticles being deposited. In contrast, the generated Cu nanoparticles impregnated TiO2 by dissolving in ammonia and exhibited catalytic activity. CH4 significantly affects Faraday efficiency relative to the amount produced because CO and H are two-electron reactions, while CH4 is an eight-electron reaction, requiring four times as many electrons. Although C2H4 is produced by Cu nanoparticles at sufficient current density, the present results show increased CH4 production. This may be due to TiO2 promoting the hydrogenation of CO2 before Cu forms the C-C bond. Further investigation is required. Conclusions In this study, TiO2 underwent treatment with various in-liquid plasma electrodes for electrocatalytic CO2 reduction. As a result, changing the electrode allowed for successful support of metal nanoparticles on TiO2, resulting in selectivity of CO2 reduction products. During the presentation, we will discuss the comparison with conductive carbon black (CB) and the changes in electrocatalytic CO2 reduction characteristics under different plasma conditions in liquid. Compared to pristine P25, the production of CO increased by 9.5-fold from 40 to 380 μmol, and CH4 increased by 2.0-fold from 20 to 40 μmol.Reference1) Sassenburg et al., ACS Appl. Energy Mater., 5, 5, 5983 (2022).2) Takagi et al., Sci. Total Environ., 902 (13), 166018 (2023). Figure 1

Corrosion Protection Evaluation of Copper Coated with a Block Copolymer and Block Coploymer/Carbon Black Nanoparticles in 3 wt% NaCl Solution

AbstractThis paper presents a successful preparation of SEBS (a copolymer polystyrene‐block‐poly (ethylene‐ran‐butylene)‐block‐polystyrene) and SEBS‐CB (SEBS‐Carbon Black nanoparticles) coatings on a copper surface following a well‐defined immersion protocol. Such coatings′ protection capacity was tested in a 3 wt% NaCl medium using potentiodynamic polarization, cyclic voltammetry (CV), and electrochemical impedance techniques (EIS). The electrochemical measurements indicate that SEBS and SEBS‐CB are cathodic‐type inhibitors mainly hindering the diffusion of oxygen molecules toward the copper substrate. It also indicates the decrease in chloride ion attack on the coated copper layer. Not only that, but it also affirms the decrease in ‘s transport to the bulk solution, resulting in our sample being further protected at more positive potential. Cu‐SEBS‐CB electrodes showed a slight improvement in corrosion protection compared to Cu‐SEBS electrodes. π‐π stacking was associated with improving the performance of these coatings. The keys functions of incorporating CB are improving the electrode conductivity and having a denser and more compact coating than that without CB. The order of inhibition efficiency obtained by potentiodynamic polarization is in good agreement with the results achieved by electrochemical impedance spectroscopy. Also, the inhibition efficiency of Cu‐SEBS and Cu‐SEBS‐CB increases with increasing the ratio of SEBS. Adsorption of SEBS and SEBS‐CB on copper surface follows the Langmuir isotherm.

A Composite Fabric with Dual Functions for High-Performance Water Purification.

The dilemma of diminishing freshwater resources caused by water pollution has always impacted human life. Solar-driven interfacial evaporation technology has the potential for freshwater production via solar-driven distillation. However, in solar-driven interfacial evaporation technology, it is difficult to overcome the problem of wastewater containing various contaminants. In this work, we propose a bifunctional fabric created by depositing titanium dioxide@carbon black nanoparticles onto cotton fabric (TiO2@CB/CF). The TiO2@CB/CF has a coupling effect that includes the photothermal effect of CB and photocatalysis of TiO2, and it can not only generate clean water but can also purify contaminated water. The resulting bifunctional fabric can achieve an outstanding water evaporation rate of 1.42 kg m−2 h−1 and a conversion efficiency of 90.4% in methylene blue (MB) solution under one-sun irradiation. Simultaneously, the TiO2@CB/CF demonstrates a high photocatalytic degradation of 57% for MB solution after 2 h with light irradiation. It still shows a good photocatalysis effect, even when reused in an MB solution for eight cycles. Furthermore, the TiO2@CB/CF delivers excellent performance for actual industrial textile dyeing wastewater. This bifunctional fabric has a good application prospect and will provide a novel way to resolve the issue of freshwater scarcity.

Investigation on the Role of Polypyrrole/Carbon Black Nanoparticles in the Electromechanical Behavior of Modified P(VDF-HFP)

Recently, the polyvinylidenefluoride-co-hexafluoropropylene P(VDF-HFP) as electroactive polymers (EAPs) has been known to have great potentials in micro electro mechanical systems (MEMs) due to their light weight, low cost, and large electrical field-induced strain. In order to enhance their electromechanical properties, the modified P(VDF-HFP) with various conducting polymers such as polypyrrole (PPy) and carbon black (CB) is considerably required. In this work, the P(VDF-HFP) as matrix was doped with different loading of PPy/CB (< 1 wt%) and the composites films were obtained by using solution casting method. The influence of filler content on the dielectric properties and the conductivity of these thin films was investigated by using LCR meter. The maximum dielectric constant of the P(VDF-HFP)/PPy-CB was 2 times larger than the pure P(VDF-HFP) without conductive fillers. At low frequency, the both dielectric loss and conductivity were found to be slightly increased as consequence of the conducting polymers, but the conductive phase has not been achieved yet. In addition, a complete set of electromechanical properties were systemically explored using the result of strain displacement under the low electric field (< 5 MV/m). During the applied electric field, the average voltage peak-to-peak was attributed to the strain yield of approximately 0.08% at 2 MV/m. These observations indicate that the synergistic effect of conductive fillers induce their electric polarization and it can be considered as one of the promising candidates for actuator applications.

Effect of Carbon Nanoparticles on the Performance Efficiency of a Solar Water Heater

Carbon nanoparticles are prepared by sonication using carbon black powder. The surface morphology of carbon black (CB) and carbon nanoparticles (CNPs) is investigated using scanning electron microscopy (SEM). The particles size ranges from 100 nm to 400 nm for CB and from 10 nm to 100 nm for CNPs. CNPs and CB are mixed with silicon glue of different ratios of 0.025, 0.2, 0.05, and 0.1 to synthesis films. The optical properties of the prepared films are investigated through reflectance and absorbance analyses. The ratio of 0.05 for CNPs and CB is the best for solar paint because of its higher solar water heater efficiency and is then added to the silicon glue . Temperature of cold water and temperature of hot water in storage tank were tabulated on hourly basis with the help of an Arduino device. The atmospheric temperature was also noted. It was observed that outlet temperature of water was attained up to 75°C as compared to the inlet water temperature of 23°C for the tank applied with CNP-based paint. The tank applied with CNP-based paint has 4 °C higher water temperature than that coated with CB-based paint after 1 month of test under sun irradiation. Based on the results, the efficiency of a solar water heater depends on the difference in temperature of inlet water and outlet of heater. The efficiency of the solar water heater coated with CNPs is around 77% but the solar water heater coated with CB has an efficiency of 67%.

In situ modification of case-hardening steel 16MnCr5 by C and WC addition by means of powder bed fusion with laser beam of metals (PBF-LB/M)

Typical high-strength products are made from carbon-rich steels possessing relatively high carbon content, thus reducing weldability. In this work, preliminary studies on designing and tailoring a low-alloyed steel for the laser-based powder bed fusion (PBF-LB/M) process by adding carbon black (C) nanoparticles and tungsten carbide (WC) particles for enhancing the material properties are provided. First, the base material 16MnCr5 is modified with different concentrations of C and WC. It was found that an increased C and WC content resulted in an elevated material hardness in the as-built state. However, this comes at the cost of a poorer processability as pore formation increased for C-modified and crack tendency increased for WC-modified 16MnCr5. When applying a post-process quenching and optional tempering heat treatment, material hardness in the range of 615 HV can be achieved for C-enriched 16MnCr5 in the tempered state, which would be suitable for bearing and gearing applications. The addition of WC particles favored an improved wear resistance which is twice as high as the one of C-modified material for similar material hardness, showing the enormous potential of WC addition for reducing the wear rate. Complementary SEM and EDX analyses show that both the dilution and bonding zone of the WC particles are affected by the processing conditions and the WC concentration. Furthermore, it was found that a nearly defect-free fabrication of WC-enriched 16MnCr5 was possible for up to 2.5 wt.-% of WC, proving that the occurring defects are highly sensitive to the WC concentration.

Effect of Potassium Alum Salt Particles on the Activation Energy of Poly(ethylene oxide) Doped with Conductive Carbon Black (CB) Nanoparticles

The electrical properties of conductive carbon black (CB) nanoparticles (0.1wt percent) doped thin films made of poly(ethylene oxide) (PEO) filled with varying amounts of the electrolyte potassium alum salt and doped with conductive carbon black (CB) nanoparticles (0.1wt percent) have been investigated. The dependence of the activation energy of the composites on frequency, temperature, and filler content was studied using the AC impedance technique. The current research looked at how activation energy changed with frequency (200-1000 kHz) and temperature (30-55oC) for composites with varied potassium alum salt concentrations: 0, 2, 4, 8, 12, and 16 wt. percent. The activation energy (Ea) values measured exhibited frequency, temperature, and filler content relationships. According to polarization processes, the activation energy of the produced sheets decreases with the potassium alum salt content in the composite and decreases with the temperature. With increasing frequency, the activation energy of the produced thin films decreases.

THE EFFECT OF ADDITION NANOPARTICLES ON SHRINKAGE PROPERTY OF ORDINARY PORTLAND CEMENT

Two types of nanomaterial: Tio2 nanoparticles (NPs) and carbon black NPs have used in this research to study their effect on compressive strength, shrinkage and flow table tests Cement mortar. The mixing ratio was 1:2.7:0.485 (cement, sand, water/cement ratio) for compressive strength test and 1:2 (cement, sand) with the water/cement ratio was a variable value for dry shrinkage test. The two nanoparticles’ ratios are (0.25%, 0.75%, 1.25 % and 1.75%) by weight of the Portland cement. The test results show that the highest value of compressive strength was obtained when using Tio2 at 1.25% wt. of cement. But when using carbon black nanoparticles, the greatest value was obtained when adding it with a ratio of 1.75 % wt. of cement. Using two NPs when added to cement mortar has a negative effect on the shrinkage value.

Improving the electroluminescence of Si nanocrystal via black silicon and silver surface plasmons

In this paper, black silicon (Si) and silver (Ag) surface plasmons were used to improve the electroluminescence (EL) intensity of silicon nanocrystals (Si-nc), and the mechanism of black Si and Ag nanoparticles enhancing the EL of Si-nc LED is analyzed. The Ag nanoparticles are introduced into Si-nc LED to generate surface plasmons. The surface plasmons radiate the local electromagnetic field, which can increase the excitation probability of Si-nc and increase the EL intensity of Si-nc LED. In addition, black silicon can improve the charge injection efficiency and light emission efficiency. The atomic force microscope (AFM) and reflectivity spectra of black silicon at different etching time, as well as the AFM and absorption spectra of Ag nanoparticles at different postannealing temperatures, were measured. Three different device structures were designed. The EL intensity of Si-nc increased by 3.2 times at the etching time of 5 minutes and increased by 4.9 times at the postannealing temperature of 200 °C, respectively. A maximal 8.5-fold EL enhancement of Si-nc was readily achieved after using the black Si as substrate and incorporating Ag surface plasmons.

Retraction: Carbon black hybrid material furnished monodisperse platinum nanoparticles as highly efficient and reusable electrocatalysts for formic acid electro-oxidation.

Retraction of ‘Carbon black hybrid material furnished monodisperse platinum nanoparticles as highly efficient and reusable electrocatalysts for formic acid electro-oxidation’ by Yunus Yıldız et al., RSC Adv., 2016, 6, 32858–32862, DOI: 10.1039/C6RA00232C

Synthesis and Characterization of Black Currant Selenium Nanoparticles (Part I)

The present study aimed to synthesize selenium nanoparticles (SeNPs) using aqueous extract of black currant as a reducing agent. The green synthesized black currant selenium nanoparticles (BCSeNPs) were identified by color change. The characterization of SeNPs was achieved by Ultraviolet-visible (UV–VIS) spectroscopy, scanning electron microscopy (SEM), X–ray diffraction analysis (XRD), and Fourier transform infrared spectroscopy (FTIR). These tests were used to detect: stability, morphology, size, crystalline nature, and functional groups present on the surface of BCSeNPs. The results revealed appearance of the brick-red color indicating the specific color of selenium nanoparticles, and UV-Vis spectroscopy showed band absorbance at 265 nm of intense surface plasmon resonance manifesting the formation and stability of the prepared BCSeNPs. The SEM image showed the prevalence of spherical selenium nanosized, XRD at 2θ revealed crystallin selenium nanoparticles, the size was in the average of 18-50 nm. Furthermore, FTIR revealed the presence of functional groups of the plant which act as stabilizing and reducing agents. In conclusion, the aqueous black currant extract can act as a reducing and capping agent to synthesize BCSeNPs in nano-scale size by a simple method

Green synthesis, characterization, antibacterial and photocatalytic activity of black cupric oxide nanoparticles

BackgroundBiogenic fabrication of nanoparticles from naturally occurring biomaterials involves plants, herbs, bacteria and fungi using water as neutral solvent, while chemical synthesis involves hazardous chemicals and leaves unwanted byproduct which unnecessarily pollute the environment. In order to prevent atmospheric pollution a safe, clean and green strategy for the synthesis of cupric oxide nanoparticles from aqueous leaf extract of Diospyros montana has been employed. D. montana of Ebenaceae family is a poisonous tropical plant which grows wild in Asia. Its extract is commonly known as fish poison. The rate of formation of NPs from plant extract is thought to be facile and rapid relative to those formed by fungi and bacteria, but it depends on the concentration of reducing chemicals available in the extract. We report, in this communication, a benign method of biogenic synthesis of cupric oxide nanoparticles (CuO-NPs) from leaf extract of D. montana and their characterization by UV–visible, FTIR, SEM, TEM, DLS, SAED and EDX analyses. Their antimicrobial activity against seven Gram-positive and four Gram-negative bacteria has been screened. Photocatalytic degradation of methylene blue by ascorbic acid as reducing agent and cupric oxide nanoparticles as catalyst has been done under sunlight.ResultsCupric oxide nanoparticles of varying size starting from 5.9 to 21.8 nm have been fabricated from aqueous leaf extract of D. montana at room temperature. The pure extract absorbs at 273 nm while CuO-NPs exhibit a broad peak at 320 nm. FTIR spectrum of the leaf extract shows the presence of a double quinonoid molecule. There are three types of CuO-NPs with different hydrodynamic radii. Their average hydrodynamic radii fall between 495 ± 346 nm. SEM and TEM images show spherical shaped CuO-NPs of different size. SAED suggests crystalline nature of CuO-NPs. They are highly polydispersed in solution. EDX analysis reveals the presence of Ca, C, O, Na and Si besides copper. Oxygen content is over 50% by mass. Reduction of methylene blue dye (MB) by ascorbic acid as reducing agent, in presence of CuO-NPs as catalyst, has been achieved in 90 s at room temperature while their reduction by ascorbic acid alone takes more than 10 min. Antibacterial activity of CuO-NPs against seven Gram-positive (Staphylococcus aureus, Streptococcus mutans, Streptococcus pyogenes, Streptococcus viridans, Staphylococcus epidermidis, Corynebacterium xerosis and Bacillus cereus) and four Gram-negative bacterial strains (Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Proteus vulgaris) has been investigated. The results indicated that NPs are highly effective against growth inhibition of Gram-positive bacteria than Gram-negative bacteria. Copper oxide nanoparticles are even more toxic than the standard antibiotic, norfloxacin.ConclusionIn this project cupric oxide NPs of 5.9–21.8 nm have been fabricated from aqueous leaf extract of D. montana. It is most inexpensive and easy process to fabricate NPs from plant material because no toxic chemicals are used. Since CuO-NPs are toxic to several Gram-positive and Gram-negative bacterial strains, attempt may be made to use them as antibacterial agent to protect food, vegetable and crops. Also, the reduction of methylene blue dye by ascorbic acid as reducing agent in presence of CuO NPs as catalyst has been done very efficiently at a rapid rate which prompts us to use them as catalyst in the reduction of dyes, other toxic materials and industrial effluents. Further investigation of other beneficial properties of CuO-NPs can also be explored.

Amorphous photonic structures with high reflective index based on incorporating Fe3O4@SiO2 core/shell colloidal nanoparticles into silica nanospheres

Amorphous photonic structures (APSs) with non-iridescent, non-fading, vivid structural colors have attracted great attention in several fields. Tremendous efforts have been dedicated to developing the effective and low-cost approaches for APSs with full-color displays. Resulting from the isotropic photonic pseudogap, APSs have non-iridescent structural colors. We demonstrate that incorporating Fe3O4@SiO2 black nanoparticles into the interspace of the periodically arranged SiO2 white nanospheres can synthesize APSs with different colors. The addition of Fe3O4@SiO2 black nanoparticles can enhance the saturation of the non-iridescent structural colors of the APSs by reducing the incoherent scattering in the visible spectrum. In this case, different non-iridescent colors originate from the different diameters of the SiO2 white nanospheres, and we obtained red, orange, yellow, green, and purple APSs with high reflective index successfully. The APSs with different colors may have potential applications in coatings, cosmetics, textiles, and displays. Moreover, as we use Fe3O4@SiO2 as the additive, APSs can be recycled through its magnetic property.

Mechanical study and molecular dynamics simulation on polycarbonate nanocomposite with carbon black and SnO2

In this work, SnO2 and carbon black (CB) nanoparticles (NPs) were used to improve the physical and mechanical properties of polycarbonate films (PC) for industrial applications. Raman spectroscopy proved the successful inclusion of the fillers within the polymeric-based nanocomposites, with a suitable dispersion without changes in the structure and morphology of PC as denoted by scanning electron microscopy (SEM) and X-ray diffraction (XRD). After doping of the PC-based nanocomposites with CB, SnO2 and CB/SnO2 NPs, both the polymer hardness and the elastic modulus of the composites were observed to increase, with the highest value achieved for PC/CB-doped ones. Thermal gravimetric analysis (TGA) and differential scanning calorimetry (DTG) indicated changes in the thermal properties of the polymer composites upon NP doping. Finally, molecular dynamics simulations were used to gain a better understanding about the interactions of PC and NPs in the nanocomposites. Simulation data obtained were in good agreement with experimental ones, which indicates that simulations can be an efficient toll in order to perform a preliminary high-throughput screening of diverse physico-chemical properties of polymeric-based nanocomposites bearing NP fillers before experimental development.

Composites Based on Thermoplastic Polymeric Matrix and Carbon Nanoparticles with Special Functional Properties

Polymer composite materials based on polypropylene matrix and carbon nanoparticles of various shapes: spherical particles - carbon black and anisotropic nanoparticles - carbon nanofibers, were obtained by the melt technology. A character of the dependences of the electrical conductivities on the concentration of carbon nanofillers has been revealed. A simulation of the electrical conductivity of the polymer composite in the region of the concentration of the filler at the threshold of the flow of electric current and below it was carried out.

The effective complex permittivity stability in filled polymer nanocomposites studied above the glass transition temperature

The temperature effecton the dielectric response of nanocomposite at low frequencies range is reported. The investigated samples are formed by a semi-crystalline ethylene-co-butyl acrylate (EBA) polymer filled with three concentrations of the dispersed conducting carbon black (CB) nanoparticles. The temperature dependence of the complex permittivity has been analyzedabove the glass transition temperature of the neat polymer matrix Tg=-75°C. For all CB concentrations, the dielectric spectra follow a same trend in frequency range 100-106Hz. More interestingly, the stability of the effective complex permittivity ɛ=ɛ' -iɛ'' with the temperature range of 10-70°C is explored. While the imaginary part of the complex permittivity ɛ'' exhibits a slight decreasewith temperature, the real part ɛ' shows a significant reduction especially for high loading samples. The observed dielectric response may be related to the breakup of the three-dimensional structurenetwork formed by the aggregation of CB particles causing change at the interfaceEBA-CB.This interface is estimated bythe volume fraction of constrained polymer chain according to loss tangent data of dynamic mechanical analysis.

Augmentation of a solar still distillate yield via absorber plate coated with black nanoparticles

Effects of utilizing nanomaterial on the solar still productivity investigated experimentally. Cuprous oxides (CuO) chosen asa nanoparticles material. The nanoparticles added to the black paint of the solar still walls to enhance the solar still performance. Experiments conducted with cuprous oxide nanoparticles weight concentrations ranged from 10% to 40%. It is found that adding nanoparticles to paint increase heat transfer rate and saline water temperature. Solar still productivity of the proposed system is higher than that for the conventional still. Results acquired that utilizing CuO nanoparticles boosted the distillate by 16% and 25% as compared to the conventional solar still (CSS) at weight fraction concentration of 10% and 40%, respectively. Payback period of the distillation system for the modified still using CuO nanomaterials is about 96days, at weight fraction 10%, which is considerable as compared by 89days for CSS.

Creating immunocompromised districts

We read the letter to the editor, Viral warts and seborrheic keratosis on tattoos: a review of 9 cases with great interest.1 Dermatologists see only what they know! Once we recognized the possibility that warts might grow preferentially in black and blue tattoo dye, we collected 7 cases over a 10-year period from one solo private practice. In this report, a patient with a pre-existing viral wart on skin adjacent to a new tattoo appears to have preferentially spread onto the immunocompromised district (Ruocco, 2009)2 created by black ink nanoparticles. This article is protected by copyright. All rights reserved.

Exposure to manufactured nanoparticles during gestation: Impact on the respiratory tract of the offspring in a mouse model

Due to several commercial applications of manufactured nanoparticles (NPs), such as silver (Ag NPs), titanium dioxide (TiO2 NPs) and cerium dioxide (CeO2 NPs), knowledge of the toxicity of those NPs is of great importance. Many studies have linked exposure to fine and ultrafine particles (from air pollution) to an increase of morbidity or mortality due to various respiratory or cardiovascular diseases. Several works have focused on the effects of pulmonary exposure to manufactured NPs. It has been shown that exposure to NPs may lead to an inflammatory response, pulmonary fibrosis and emphysema. However, less is known on the effect of exposure to NPs on the offspring. It has been reported that exposure during pregnancy to TiO2 NPs and SiO2 NPs is associated with fetal hypertrophy, neurotoxicity, and exposure to carbon black NPs induced renal disease in the offspring. NPs may interfere with normal fetal lung development. In addition, a recent study reported that pulmonary exposure of newborn mice to TiO2 NPs was associated with pulmonary inflammation and impaired lung development. Therefore, the aim of this study is to assess the impact of exposure by the respiratory route to various NP during pregnancy on lung development of the offspring in a mouse model, and to determine the key parameters involved in lung alterations. For this study, we used three metal NPs: TiO2, Ag, and CeO2 with the same size and shape, to assess the impact of NPs physico-chemical properties in the potential effects on lung development. C57Bl6/J pregnant mice were exposed weekly to 100 μg NPs by nonsurgical intratracheal instillation. Analysis (biological, histological and functional) of the lungs of the offspring were made at different time of lung development: one day before delivery (18GD for gestational day), 14 days after birth (pulmonary alveolization) and 21 days after birth (lung maturity). Preliminary results show that the exposure to TiO2 NPs during pregnancy did not affect the number of fetuses per litter, or the weight of uterus and placenta. However, the weight of fetuses whose mothers were exposed to TiO2 NPs is significantly decreased. A decrease of VEGF-A gene expression, involved in lung development, was also observed at 18GD. These preliminary results suggest that exposure to TiO2 NPs during pregnancy could affect the development of the offspring. For the remainder of this work, pregnant mice will be exposed to other NPs (Ag and CeO2) in order to see if this effect depends on the type of NP. Moreover additional analyzes will be performed to confirm whether lung alterations are observed at later times after birth, and to understand the key parameters and mechanism associated with these changes.