Petroleum hydrocarbons (PH) toxicity and bioaccumulation in aquatic organisms have been investigated for almost 50 years. Continuous oil spillages necessitate a further understanding of the toxicological effects of PH on brachyuran crabs. Crabs can be exposed to PH through various routes such as the water column, sediment and diet. Numerous investigations have been dedicated to evaluating PH toxicity on different life stages of crab species, but the majority of them have focused on the blue crab Callinectes sapidus as it represents an edible and favourable seafood commodity for human consumption. The objective of the review is to critically assess studies related to PH toxicity on different life stages of 41 crab species representing 13 families across the world. Several physiological, biochemical and genetic endpoints of marine crabs were evaluated in addition to the sublethal effects of PH on crab metabolism, behaviour, moulting, growth and survival. A concise summary of PH deleterious effects on different taxonomic species of marine crabs is discussed and provides evidence that crabs can be used as indicator organisms of biomarker significance for marine pollution. Overall, larval stages appeared to be the most sensitive to the deleterious effects of PH compared with juveniles and adults. However, adult stages have received more research attention than other life stages, followed by larval stages, and juvenile stages are the least investigated stages with respect to PH toxicity. Finally, hepatopancreas and gills were the organs where greatest accumulation of PH was recorded.

We extend our recent 2D trajectory (x–y plane) and diffusion coefficient data of ceria particles near a glass surface obtained at pH 3, 5, and 7 using evanescent wave microscopy and video imaging to 3D trajectories by analyzing the separation distance between the particles and the glass surface in the vertical z-direction. Mean squared displacement (MSD3D) of ceria particles was calculated to quantify 3D trajectories. Three-dimensional diffusion coefficients were obtained from the MSD3D curves and were compared with two-dimensional diffusion coefficients. By analyzing the MSD curves, we found that ceria particles exhibited only confined motion at pH 3 and 5, while both confined and Brownian motion were showed at pH 7. We also evaluated the cleaning ability of DI water adjusted to pH 10 and 12 to remove ceria particles from glass surfaces and related the results to the calculated trajectory, diffusion coefficient, and interaction potential data.

As the minimum feature size of integrated circuit elements has shrunk below 7 nm, chemical mechanical planarization (CMP) technology has grown by leaps and bounds over the past several decades. There has been a growing interest in understanding the fundamental science and technology of CMP, which has continued to lag behind advances in technology. This review paper provides a comprehensive overview of various chemical and mechanical phenomena such as contact mechanics, lubrication models, chemical reaction that occur between slurry components and films being polished, electrochemical reactions, adsorption behavior and mechanism, temperature effects, and the complex interactions occurring at the wafer interface during polishing. It also provides important insights into new strategies and novel concepts for next-generation CMP slurries. Finally, the challenges and future research directions related to the chemical and mechanical process and slurry chemistry are highlighted.

Chemical modification of kraft lignin from Pinus caribaea (Sénécl.) W.H.G. was performed with cyclic anhydrides (succinic, maleic and glutaric) assisted by microwave radiation. Esterification of the lignin was proven by the mass increase and Fourier Transform Infrared (FTIR) spectroscopy. Aqueous suspensions of bentonite were prepared using unmodified lignin and the corresponding derivatives as dispersants. Suspensions were evaluated in term of stability, viscosity and dispersibility. The esterified derivatives showed better dispersing properties than the neat lignin because the derivatives-based suspensions were less viscous. The dispersing properties of lignin and the esterified derivatives were compared with those of a high-molecular-weight lignin fraction obtained by ultrafiltration. In addition, two commercial lignosulfonate dispersants commonly used for drilling muds were used as references. The high-molecular-weight esterified derivatives proved to be better dispersants than their unfractionated counterparts. In general, the esterified derivatives showed similar properties to those obtained with the commercial dispersants. Modified lignin based on succinic-, maleic- and glutaric-anhydride is expected to play a key role in the design of novel bio-based dispersants for drilling-mud applications.

MnO2-multiwalled carbon nanotube (MWCNT) supercapacitor electrodes with active mass loading of 30-45 mg cm-2 were prepared. In method 1, MnO2 and MWCNT were dispersed using 3,4-dihydroxybenzaldehyde (DHB) and toluidine blue (TD), respectively. The Schiff base formation between amino group of TD and aldehyde group of DHB facilitated improved mixing of MnO2 and MWCNT. In method 2, gallocyanine (GC) was used as a co-dispersant for MnO2 and MWCNT. The catecholate type bonding of DHB and GC allowed for adsorption of the dispersant molecules on MnO2 nanoparticles. The electrodes, prepared by method 1 showed higher capacitance, compared to the electrode, prepared by method 2. The highest capacitance of 7.8 F cm-2 (173 F g-1, 139 F cm-3) was obtained at a scan rate of 2 mV s-1 and active mass loading of 45 mg cm-2.

The microfluidic production of droplets is a well controllable process, which allows templating small spherical containers that can subsequently be transferred into uniformly sized polymer microgel particles by a crosslinking reaction. Recently, the per-channel production rate of N-isopropylacrylamide (NIPAAm) droplets (w-phase) dispersed in a low-viscosity fluorocarbon oil (o-phase) could be increased by a delayed surfactant addition, while maintaining the advantageous dripping regime. Here it should be evaluated, if delayed surfactant addition can be applied to enhance droplet production also for high viscosity continuous phases, which is associated with a change to an inviscid drop scenario compared to the previously used setting of viscous drops. It could be illustrated that the concept of delayed surfactant addition holds true also for viscous continuous phases and allows ∼8 fold increased flow rates in the dripping regime. Surprisingly, the droplet size increased at higher total flow rate with constant flow rate ratios of w- and o-phases, which is discussed in the light of viscous dissipation, microchannel bulging and viscosity of the continuous phase. More rigid microchannels such as from glass may allow further exploring this phenomenon in the future.

Calcium hydroxide (Ca(OH)2) is one of the most interesting materials used to consolidate stone sculptures, monuments, mortars or wall paintings. In this study, we reported on the synthesis and characterization of surface modified Ca(OH)2 nanoparticles as a dispersion with enhanced kinetic stability and the applications for the conservation of sandstone monuments. Uniform hexagonal Ca(OH)2 nanoparticles (∼35nm) were obtained by mixing NaOH and NaCl aqueous solutions at 100∼175oC using homogeneous-phase reactions. It was further demonstrated that 3-(Methacryloyloxypropane oxygen) trimethoxysilane surfactant agent can significantly reduce agglomeration and simultaneously improve specific surface area of as-synthesized Ca(OH)2 nanoparticles. Brunauer-Emmett-Teller (BET) measurement showed that specific surface area of modified Ca(OH)2 nanoparticles reaches up to ∼48.78m2/g, about 2.5 and 3.4 times higher than that of unmodified and commercial ones, respectively. The kinetic stability of Ca(OH)2 despersion can be further enhanced and its viscosity can be decreased by optimizing the ratio of ethanol and n-propanol. Especially, a technique, which combined the Ferroni-Dini method and dispersion of Ca(OH)2 nanoparticles with enhanced kinetic stability, was proposed to effectively desalinate and consolidate the decayed stone, as evidenced by significant decreases of the porosity and concentration of detrimental Cl- and SO42- ions in the severely decayed sandstone samples from the Yungang grottoes.

The homogeneous dispersion of carbon nanotubes (CNTs) in a polymer matrix is a critical parameter that significantly affects the electrical and mechanical properties of CNT-based composite materials, and represents an important challenge to overcome during the manufacturing process of these materials. In our work we used double-stranded DNA to facilitate the dispersion of multi-walled CNTs in solution prior to the integration in epoxy resin PRIME 20 LV. Composites containing DNA-wrapped CNTs were prepared using sonication at 0.5 wt.% CNT loading and the dispersion level in the composite CNT/PRIME 20 LV was observed under an optical microscope. Nanoindentation experiments were conducted to determine the local mechanical properties of the CNT/PRIME 20 LV composites films after cure, showing a significant improvement in their distribution across the sample surface as a result of the enhanced CNT dispersion by DNA. An electrical test to assess the stability of the CNTs dispersion in the resin was developed by measuring the conductivity of the composite mixture before cure in time. Results of the electrical measurements indicate that the CNT/PRIME 20 LV mixture with DNA-wrapped CNTs is stable for several days after preparation.

Contemporary methods for dispersion of carbon nanotubes in water and non-aqueous media are discussed. Main attention is paid to ultrasonic, plasma techniques and other physical techniques, as well as to the use of surfactants, functionalizing and debundling agents of distinct nature (elemental substances, metal and organic salts, mineral and organic acids, oxides, inorganic and organic peroxides, organic sulfonates, polymers, dyes, natural products, biomolecules, and coordination compounds).

Transparent films of platinum nanoparticles on graphene nanohybrids were synthesized in a two-step process. Reduction of homogeneously dispersed Pt precursor and graphene in water and solution coating/annealing afforded thin films with high catalytic performance as counter electrodes in dye-sensitized solar cells (DSSC). The requisite dispersant consisting of poly(oxyethylene)-(POE) segments and cyclic imide functionalities allowed the in-situ reduction of dihydrogen hexachloroplatinate by ethanol and the formation of nanohybrids of graphene-supported Pt nanoparticles at 4.0 nm diameter. Characterizations of polymeric dispersants by Fourier-transform infrared spectroscopy, thermogravimetric analysis, and nanohybrids by transmission electron microscope were performed. After screening various compositions of Pt/graphene, the nanohybrid film at the specific ratio of 5/1 by weight was fabricated into a counter electrode (CE) for DSSC by the solution casting method. The evaluation of cell performance demonstrated the most improved power conversion efficiency of 8.00%. This is significant achievement in comparison with 7.14% for the DSSC with the conventional platinum sputtered CE. Furthermore, the solution casting method allows the preparation of transparent CE films that are suitable for using as rear-illuminated DSSC. The approach was proven to be feasible by measuring the cell efficiency under rear light illumination. The power efficiency up to 7.01%, comparable to 8.00% by a normally front illumination, has been accomplished. In contrast, the rear illumination at merely 2.36% efficiency was obtained for the DSSC with sputtered platinum CE. Analyses of cyclic voltammetry, electrochemical impedance spectra were well correlated to the high efficiency of the performance caused by this nanohybrid film.

We like to report a novel conductive film containing graphene-silver nanohybrids from the process of solution coating and annealing at low-temperature for melting silver nanoparticles (AgNPs) into interconnected Ag matrice on surface. The fabrication required the assistance of a home-made polymeric dispersant, poly(oxyethylene)-segmented imide (POE-imide), for homogenize the AgNPs and graphene in hybridized form. The intermediate dispersion of AgNPs at 10–25 nm diameter on the surface of 2D-graphene were characterized and subsequently subjected to solution coating into thin films. Under the annealing temperature as low as 160 °C, the films exhibited a high electric conductivity or low sheet resistance at 2.4×10–1 Ω/sq (equivalent to 7.9×104 S/cm). It is noteworthy that the significant point of low-temperature annealing at 160–170 °C that is attributed to the fast deterioration and degradation of the POE-imide organics kinetically before the AgNP coalescence and melting. Furthermore, the comparisons of using silicate clays and carbon nanotubes in replacing the 2D graphene for hybridizing Ag had revealed the different morphologies in Ag networks. The findings of using the polymeric dispersion for synthesizing nanohybrids may open up a new avenue for making films with integrated properties of flexibility, transparency and high conductivity for a host of electronic applications.

A novel polymer dispersant, poly(oxyethylene)-segment imide (POEM) in the structure was incorporated in the nanocrystalline TiO2 film as the electrode. The uses of the dispersants could disperse TiO2 by decreasing the van der waals force among the nanoparticles, observed by TEM. The resultant TiO2/POEM film as the photoanode rendered the dye-sensitized solar cell (DSSC) with enhanced performance. By comparing to the traditional photoanode composing of polyethylene glycol (PEG) dispersed TiO2, the POEM dispersed TiO2 provided large surface area and high roughness in the dye adsorbed film. Furthermore, the fabricated TiO2/POEM photoanode has a better light-scattering property which contributes to the improvement for the short-circuit current density (Jsc) and the power-conversion efficiency (_) of the DSSC to be 19.1 mA cm-2 and 8.7%, respectively. The performance is superior to 13.2 mA cm-2 and 7.34% for a DSSC with the photoanode containing TiO2/PEG.

Nanoparticles (NP) are introduced in a growing number of commercial products, including food and beverage, daily use hygiene products such as toothpaste, or orally-administered drugs. To study the possible toxicity of these nanoparticles, a model system is the in vitro response of eukaryotic cells to the presence of NP. However, to understand the observed effects, it is clear that good physical and chemical characterization of NP, and in particular of their dispersion are needed. Indeed, the expected effects should be different if the study is dealing with agglomerates or isolated nanoparticles. For fundamental understanding, it appears important to work with nanoparticles as well dispersed as possible while being in relevant biological condition, i.e. cellular culture cell.

In this context, we have studied the dispersion of a very common industrial titania NP (Degussa P25 produced in ton quantities). When dispersed in water, the suspensions of NP appear stable for weeks.. When transferred in the cell culture medium (DMEM) or if directly dispersed in DMEM, strong evolution of size is seen as well as sedimentation. To address this problem, we have compared different ways, coming from materials science, of dispersing NP in water with the idea to break in a preliminary step some of the necks between nanoparticles. The effect of dry ball milling, liquid ball milling, size of the balls and Ultrasonic dispersion will be compared. The best results were obtained from high power ultrasonic dispersion. To avoid direct aggregation, when going to DMEM, a “surfactant” relevant with biological studies (Foetal Bovine Serum (FBS)) was added in the suspension in order to coat the nanoparticles prior to transfer in DMEM (or other cell media). The result obtained with various surfactants and cell media will be presented. It must be noted that our best results were obtained in the FBS + DMEM medium.

Graphene oxide (GO) is a nonstoichiometric two-dimensional material obtained from the chemical oxidation and exfoliation of graphite, which has recently attracted intense research interest as a precursor for bulk production of graphene. GO has long been believed to be hydrophilic due to its dispersibility in water. Recent work in our group, however, has found that GO is actually a two-dimensional amphiphile; the edge of the sheet-like material is hydrophilic, while the basal plane of the material contains more hydrophobic graphitic nanodomains. To prove the concept, we demonstrate GO’s surface activity at an air-water interface, as well as its utility in dispersing insoluble aromatic materials such as toluene, graphite, and carbon nanotubes in water. As a colloidal surfactant which can be converted to a conducting material, GO presents unique possibilities for aqueous solution processing of organic electronic materials.

Two molecular modes of amphiphilic block copolymer-carbon nanotube interactions have been suggested in the literature, involving the adsorption of either individual block copolymer molecules or of multimolecular, spherical block copolymer micelles on the carbon nanotube. In both cases, the nature of stability imparted to the dispersion of nanotubes is kinetic, controlled by the steric barrier imposed by the adsorbed individual molecules or micelles. In this study we propose an alternate mode of molecular interaction, wherein the block copolymer molecules self-assemble around the nanotube to generate a thermodynamically stable aqueous dispersion. The possibility of such micellar solubilization of nanotubes is examined by constructing a phenomenological theory of nanotube solubilization. Illustrative calculations performed for polyethylene oxide- polypropylene oxide – polyethylene oxide (PEO-PPO-PEO) triblock copolymers show that they are capable of solubilizing carbon nanotubes in aqueous solutions. While the block copolymer molecules that spontaneously form cylindrical micelles are most likely to solubilize the nanotubes, other copolymers whose natural curvature is spherical or lamellar also are capable of forming cylindrical micelles around the nanotubes. Most interestingly, the solubilization is found to be size specific suggesting that this can be developed into a practical method to fractionate carbon nanotubes by size or chirality.

Dispersed uniform spherical silver particles were prepared in the absence of a protective colloid by rapidly mixing concentrated isoascorbic acid and silver-polyamine complex solutions. By varying the nature of the amine, temperature, concentration of reactants, silver/amine molar ratio, and the nature of the silver salt, it was possible to tailor the size of the resulting metallic particles in a wide range (80 nm to 1.3 μm). The silver spheres were formed by aggregation of nanosize subunits, the presence of which was detected by both electron microscopy and x-ray diffraction. Due to its simplicity, high metal concentration, and the absence of polymeric dispersants, the described method represents an advantageous route to manufacture cost-effectively dispersed uniform silver particles for electronic applications.

In this study, flotation of oxidised ores rich in copper and cobalt from Mupine deposit in the Democratic Republic of Congo had been investigated. This ore contains 4.85% copper, 0.16% cobalt. The recovery of copper and cobalt was performed using flotation to increase the concentration of copper and cobalt. Flotation of the oxidized ore was performed with fatty acid type Rinkalore. Copper and cobalt present in the ore were concentrated with optimal doses of sodium silicate, Rinkalore mixture of 500 g/t, 1500 g/t respectively and optimum tall oil and pH of 23% and 9.5 respectively. The influence of Rinkalore Bioex, Rinkalore Booster Q, pH and sodium silicate on optimum operating conditions were studied. Improved performance of operating conditions was obtained with the mixture of reagents Rinkalores 10 and Booster Q. Primary feed titrating 8.70% copper and 0.31% cobalt respectively had a recovery yield of 53% and 34% respectively, and rougher concentrate titrating 8.13% copper and 0.33 % Cobalt respectively had a recovery yield of 97% and 70% respectively.

Starch suspension proves to be a useful matrix for the hydrolytic route to metal oxide nanoparticles, due to its size-stabilization effect, which works also at high temperatures. To understand the type of interaction between the organic part and the oxide particles, various parameters, such as viscosity, temperature, degree of polymerization, and organic/inorganic kinds of dispersant, are tested through x-ray diffraction (XRD), transmission electron microscopy (TEM), solid-state nuclear magnetic resonance (NMR), and thermogravimetric mass spectra (TG–MS) analyses of the obtained SnO2 nanopowders. Results highlight the unique role of starch compared with other hydrophilic dispersants that do not ensure effective size stabilization on curing up to 600 °C. The proof comes from the study of pyrolysis of the residual organic groups surrounding the particles. They are chelating carboxylic species that prevent the coalescence among metal oxide nanoparticles.

The preparation of BaMgAl10O17:Eu2+ (BAM) blue phosphor layer for a plasma display panel by the addition of a newly designed energetic dispersant (hereafter referred to as SAIT7) and its resulting photoluminescence (PL) efficiency is investigated. The addition of SAIT7 increases the maximum solids loading of BAM phosphor paste from 27.91 to 35.87 vol% and yields a highly packed microstructure of the phosphor layer. The PL intensity is increased by 7.57% compared to the BAM blue phosphor layer prepared without SAIT7. In conclusion, the addition of SAIT7 increased the packing density of the phosphor layer and resulted in improved luminescent properties of the phosphor layer.

Magnesium hydroxide nanoneedles and nanorods were synthesized by reverse precipitation in the presence of polyethylene glycol (MW 1000) at ambient temperature. The obtained magnesium hydroxide crystals were characterized in terms of morphology, particle size, crystal structure, and thermal stability by high-resolution transmission electron microscopy, x-ray diffraction, infrared spectroscopy, and thermogravimetric and differential thermal analysis. The experimental results show that the growth of magnesium hydroxide crystals and the dispersivity of the nanostructures were greatly influenced by polymer dispersant. The mechanism of the formation of magnesium hydroxide nanorods and nanoneedles was also proposed.