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.

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).

The present paper deals with the investigation of the mechanisms of TiO2 nanotubes formation on titanium surfaces during anodization process. The samples were made of pure Ti Grade-2 and Ti-6Al-4V alloy. They were grinded, etched with 0,5 wt. % HF acid and anodized. The anodization was done in electrolyte containing 0,5 wt. % HF acid using DC power supply with graphite electrode as cathode. The samples were investigated by SEM, EDAX and XRD analysis. The results show two different mechanisms of formation of TiO2 nanotubes on the surfaces of both materials. During the anodization process the oxide formations, obtained on the pure Ti surface after etching, are oxidized to nanorods; the area between them is also oxidized and connects them. This thin oxide layer grows in the metal depth while the nanorods are dissolved thus forming the porous sponge-like structure which is further transformed in tubular. While on the surface of Ti-6Al-4V alloy oxide nanonuclei originate which transform their shape from nanoseed to bowl-like with clearly pronounced bottom and walls, growing in tubular structures. The type of the material defines the surface morphology after etching. Thus obtained morphology influences on the processes running rate in different micro-regions determining origination of the titanium nanotubes on different stage as well as by different mechanism. The field-enhanced oxidation and field-enhanced dissolution are the main processes for formation of TiO2 nanotubes during anodization. In the regions with prevalent oxidation processes the TiO2 nanotubes are formed earlier while in the regions with dominant dissolution processes the TiO2 nanotubes are formed on the later stage.

There is a substantial interest in finding materials with high nonlinear optical (NLO) properties of materials because of its attractive applications in optical limiting for safety protections. In an effort to develop highly performing optical limiting materials, recently we have found that fluorination of graphene oxides leads to improvement in their NLO properties.