A stable magnetic nanocomposite of collagen and superparamagnetic iron oxide nanoparticles (SPIONs) is prepared by a simple process utilizing protein wastes from leather industry. Molecular ...interaction between helical collagen fibers and spherical SPIONs is proven through calorimetric, microscopic and spectroscopic techniques. This nanocomposite exhibited selective oil absorption and magnetic tracking ability, allowing it to be used in oil removal applications. The environmental sustainability of the oil adsorbed nanobiocomposite is also demonstrated here through its conversion into a bi-functional graphitic nanocarbon material via heat treatment. The approach highlights new avenues for converting bio-wastes into useful nanomaterials in scalable and inexpensive ways.
Here, we design and develop high-power electric double-layer capacitors (EDLCs) using carbon-based three dimensional (3-D) hybrid nanostructured electrodes. 3-D hybrid nanostructured electrodes ...consisting of vertically aligned carbon nanotubes (CNTs) on highly porous carbon nanocups (CNCs) were synthesized by a combination of anodization and chemical vapor deposition techniques. A 3-D electrode-based supercapacitor showed enhanced areal capacitance by accommodating more charges in a given footprint area than that of a conventional CNC-based device.
Fluorination of carbon nanomaterials has many advantages due to the unique nature of the carbon–fluorine (C–F) bond. In this work, we report the optical power limiting properties of fluorinated ...graphene oxide (F–GO) using the optical z-scan technique. In addition, we used the photoacoustic technique to gain insight into the nonlinear processes involved in the optical limiting of samples. The photoacoustic technique enabled us to confirm that optical limiting observed in F–GO at low fluence arises from nonlinear absorption, while that at higher fluence is due to nonlinear scattering. Moreover, we found that F–GO has high nonlinear absorption and nonlinear scattering and its optical limiting threshold is about an order of magnitude better than that of graphene oxide (GO).
► SMAT enables graded layer structure with nano-sized grains at surface ► SMAT increase surface roughness, crystalline imperfections and microstrain ► Surface nanocrystallization promotes passivity ...and increases corrosion resistance ► Increase in microstrain and defect density decreases the corrosion resistance
The influence of surface mechanical attrition treatment (SMAT) on the corrosion behaviour of AISI 409 grade stainless steel in 0.6
M NaCl was studied. SMAT using 2
mm ∅ 316L stainless steel (SS) balls for 15, 30 and 45
min and 5
mm ∅ balls for 15
min offers a better corrosion protective ability. In contrast, treatment using 5
mm ∅ balls for 30 and 45
min and by using 8
mm ∅ balls for 15, 30 and 45
min, induces microstrain and defect density that results in a decrease in corrosion resistance.
► ZM21 Mg alloy offers a higher corrosion resistance than CP Mg. ► Mg(OH)
2 and aragonitic CaCO
3 are the corrosion products on CP-Mg and ZM21 Mg alloy. ► Thickening of the corrosion product layer is ...delayed in CP Mg. ► ZM21 Mg alloy is a promising candidate for degradable implant.
Evaluation of the corrosion behavior of commercially pure magnesium (CP-Mg) and ZM21 Mg alloy immersed in Ringer’s solution for 92
h by electrochemical impedance spectroscopy (EIS) is addressed. The formation of a compact layer of well-developed rod-like aragonitic CaCO
3 crystals and its subsequent thickening with increase in immersion time offers a higher corrosion protective ability for ZM21 Mg alloy. The formation of a mud-crack pattern and a large number of clusters of needle-like crystals offers a relatively lower corrosion resistance for CP-Mg. The study suggests that ZM21 Mg alloy is a promising candidate material for the development of degradable implants.
Strong in-plane bonding and weak van der Waals interplanar interactions characterize a large number of layered materials, as epitomized by graphite. The advent of graphene (G), individual layers from ...graphite, and atomic layers isolated from a few other van der Waals bonded layered compounds has enabled the ability to pick, place, and stack atomic layers of arbitrary compositions and build unique layered materials, which would be otherwise impossible to synthesize via other known techniques. Here we demonstrate this concept for solids consisting of randomly stacked layers of graphene and hexagonal boron nitride (h-BN). Dispersions of exfoliated h-BN layers and graphene have been prepared by liquid phase exfoliation methods and mixed, in various concentrations, to create artificially stacked h-BN/G solids. These van der Waals stacked hybrid solid materials show interesting electrical, mechanical, and optical properties distinctly different from their starting parent layers. From extensive first principle calculations we identify (i) a novel approach to control the dipole at the h-BN/G interface by properly sandwiching or sliding layers of h-BN and graphene, and (ii) a way to inject carriers in graphene upon UV excitations of the Frenkell-like excitons of the h-BN layer(s). Our combined approach could be used to create artificial materials, made predominantly from inter planar van der Waals stacking of robust bond saturated atomic layers of different solids with vastly different properties.
The establishment of covalent junctions between carbon nanotubes (CNTs) and the modification of their straight tubular morphology are two strategies needed to successfully synthesize nanotube-based ...three-dimensional (3D) frameworks exhibiting superior material properties. Engineering such 3D structures in scalable synthetic processes still remains a challenge. This work pioneers the bulk synthesis of 3D macroscale nanotube elastic solids directly via a boron-doping strategy during chemical vapour deposition, which influences the formation of atomic-scale "elbow" junctions and nanotube covalent interconnections. Detailed elemental analysis revealed that the "elbow" junctions are preferred sites for excess boron atoms, indicating the role of boron and curvature in the junction formation mechanism, in agreement with our first principle theoretical calculations. Exploiting this material's ultra-light weight, super-hydrophobicity, high porosity, thermal stability, and mechanical flexibility, the strongly oleophilic sponge-like solids are demonstrated as unique reusable sorbent scaffolds able to efficiently remove oil from contaminated seawater even after repeated use.
•SMAT of 304 SS induced mechanical twins, martensite phase and dislocations.•SMAT increased the surface roughness and corrosion rate of 304 SS in 0.6M NaCl.•Current–time curves indicate formation of ...defective passive film on SMATed 304 SS.•Increase in roughness, martensite, dislocations nullify beneficial effect of SMAT.
The influence of surface mechanical attrition treatment (SMAT) on the corrosion behaviour of AISI 304 stainless steel in 0.6M NaCl was studied. SMAT of 304 SS induced plastic deformation, enabled formation of mechanical twins and strain induced ά-martensite phase, increased the surface roughness and imparted compressive residual stress. SMAT caused a deleterious influence on the corrosion resistance of 304 SS in 0.6M NaCl. Double log plots of current–time transients at 25mV(SCE) indicate formation of defective passive film on SMATed 304 SS. Increase in surface roughness, strain induced martensite and dislocations nullify the beneficial influence of surface nanocrystallization.
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