Recent Patents on Materials Science - Volume 7, Issue 1, 2014

In this article, patents and literature about the synthesis and potential applications of titania nanotubes for photocatalytic and photovoltaic devices are presented. Oxidation of water by titania thin films was reported in 1972 for the first time. In the following years, titania nanoparticles, nanorods and nanotubes have been intensively studied for this and other potential applications. Potential applications for photochemical oxidation of water are in the areas of water treatment for removing organic contaminants and microorganisms and hydrogen production. Other exciting potential applications of titania nanotubes are in the generation of electric energy in solar cells, electric charge storage, and in coatings for endoprosthesis. The considerably higher surface area of titania nanotubes compared with nanorods and nanoparticles of the same size significantly increases the efficiency of devices based on titania nanotubes, especially for surface controlled applications such as water oxidation and solar power generation.

Gold nanoparticles (AuNPs) are one of the most widely studied nanomaterials in the last decade, and are emerging as promising agents in cancer management. Gold nanostructures in varying size and shape, such as rods, triangles, hexagons, octagons, cubes, nanowires, nanospheres, etc. could be synthesized using various well-established physical and chemical techniques. Synthesis of AuNPs, using green chemistry approaches that utilize various materials of biological origin, such as proteins, polysaccharides, microorganisms, plant and cell extracts, have received increasing attention. AuNPs have numerous physical assets that make them appealing for applications in cancer management, including imaging, drug delivery, photothermal therapy and many more. Considering the widespread impact of AuNPs in cancer, an increasingly large number of patents have been awarded for the synthesis and medical applications of AuNPs. Owing to the importance of AuNPs in cancer management, the present review focuses on their modes of synthesis and widespread applications in cancer management, with special reference to recent patents.

Antimicrobial materials are being developed to prevent the growth, spread and transfer of harmful microorganisms such as bacteria and fungi, as well as to actively disable these microorganisms for the reduction of infections in public, industrial and healthcare environments. This paper demonstrates the most up-to-date patents and research in the area of metal oxides showing antimicrobial activity and discusses their properties and applications. A review of an innovative antimicrobial surface technology, which is based on the formation of an acidic surface deteriorating cell growth and proliferation is presented. The properties of the novel materials such as molybdenum trioxide and tungsten trioxide and their fabrication methods and general mechanism, which describe antimicrobial effectiveness, are discussed briefly. Recent advances, including the influence of morphology and durability of molybdenum and tungsten oxide on the activation of an antimicrobial surface are summarized. The investigated method is facile and suitable to produce long lasting antibacterial composites, useful for inanimate surfaces, which are used in public environments.

In this article selected synthesis routes of ceria based nanoparticles and applications related to their unique redox behaviors are reviewed. The capability to switch valence states for cerium ions in oxides renders ceria a widely used compound in disparate fields, such as catalysis, environmental remediation, and free radical scavenging. Cerium ions can change their electronic charge between [Ce3+] and [Ce4+], which allows to absorb oxygen into the lattice or release it into the surroundings. This reaction occurs according to the environmental conditions, but it can be influenced and altered by ulltraviolet light. Although the exchange of the cation’s valence state is also observed in bulk ceria, the property is most utilized in applications with nanosize particles. The review paper is based on the following patents: US8431506, EP1920832, WO2012036786, US20120070500, US20130251756, US7686976, US8066874, US8252087, US8349764, US8435602, US8568538, US20090302275, US20110124488, US20130195927 and US20130273659.

A large number of patents have been recently devoted to the development of rapid molding technology using metal arc spraying with high-melting-point and high-hardness metals (carbon and alloy steels). Manufacturing arcspraying dye is attractive because not only is the material relatively cheap but the dye shell also has properties of high hardness and high strength that greatly improves the service life of the spraying dye. The application scope of the spraying dye is thus expanded to provide better forming precision for the manufacture industry. Among these patents is a highmelting- point metal mold shell non-internal stress rapid manufacturing process and device. This patented technology involves the use of a high-melting-point metal wire material as self-fluxing electrode and arc, and extremely high temperature generated by gas discharge is used as a heat source. The high-melting-point metal material is atomized in a molten state under high-speed gas flow of compressed gas, and the molten particles are sprayed and deposited on the alloyed master mold (matrix) surface. In this paper, the bonding strength between coating and matrix in arc spraying 3cr13 was experimentally investigated. The coating formation principle and the bonding method between the coating and the matrix were analyzed. Furthermore, the effects of spraying distance, matrix preheating temperature, and matrix surface roughness on bond strength were discussed. The experimental results showed that the bond strength between coating and matrix initially increased and subsequently decreased with increasing spray distance. The maximum bond strength was 15.8MPa at a spraying distance of 200mm. Higher particle speed results in higher particle flatness rate and higher bond area between particle and matrix. Moreover, matrix preheating temperature also has a significant effect on bond strength; bond strength gradually increased along with increasing temperature. The bond strength between coating and matrix initially increased and then decreased with increasing surface roughness (Rz). When Rz was near 0.5mm, the bond strength between coating and matrix reached the maximum value.

In this paper, a novel rheological measuring apparatus was designed, which introduced an additional sinusoidal vibration in parallel to the extruding direction of melt polymer. Rheology of melted polypropylene filled with CaCO3 particles in two amounts of filler (i.e., with 3 and 20 %wt) during capillary melt-extrusion was investigated respectively. The effects of vibration parameters on flow viscous behavior were studied. Compared with the steady extrusion, the apparent viscosity of filled system decreased remarkably with the increase of vibration frequency and amplitude. The apparent viscosity reached to the minimum value as vibration frequency was about 8Hz. When the filled percentage of CaCO3 is low, the response of apparent viscosity is more distinct with increase in vibration parameters. Few recent patents are also discussed.

The present study describes a design of a contrivance for the generation of triboelectricity. Three polymer films, Chitosan (Chit), poly vinyl alcohol (PVA) and Chit/PVA blend were rubbed against an ultra high molecular weight polyethylene (UHMWPE) sheet utilizing the contrivance for which, a patent has been filed. The constructed contrivance utilized compressed air and pneumatic pistons to engender the to and fro forms of kineticism for engendering the static charges. The results of the study showed that the voltage recorded in the three polymer films at room temperature ranged from 14mV-88mV. The surface roughness of the three polymer films was evaluated and their role in the generation of triboelectric charges was discussed. It was evident from the results that the roughness of PVA was four times more than that of Chit and that upon coalescing the two polymers, the resulting film had a roughness value lying between those for Chit and PVA. Higher surface roughness was associated with higher wear rates which contributed to the generation of triboelectricity. The present invention is a simple contrivance having scope for further ameliorations and with potential applications in industries such as copiers, laser printers, medical applications, textiles and armed forces.

We fabricated miniature yachts whose bottoms are coated with different water contact angle-materials, and investigated on the direct correlation between the water contact angle and the sailing velocity. As a result, the sailing velocity increased with increasing in the water contact angle of the yacht bottom. We considered that the rough surface of the yacht bottom, coated with the dispersion containing super water-repellent silica nanoparticles, may decrease contact area with water, resulting in drag reduction and subsequently increasing the sailing velocity. We also briefly reviewed recent patents (US0330340 (2010); US8258206 (2012); US6994045 (2006); US20120247383 (2012); CN200780042283 (2011); CN201110396837 (2011); CN201110167924 (2011); CN201010555247 (2011); WO2012015700 (2012)) on drag reduction by super water-repellent surfaces in this paper.

(S, N)-codoped TiO2 nanotubes were hydrothermally fabricated by treating solvothermally synthesized (S, N)- codoped TiO2 nanoparticles in a NaOH aqueous solution. As-fabricated nanotubes were amorphous but transformed to crystalline anatase after solvothermal treatment in an isooctane solution containing thiourea. X-ray diffraction, transmission electron microscopy, and ultraviolet-visible spectrophotometry were used to characterize the codoped TiO2 nanotubes and nanoparticles. The content of nitrogen and sulphur reached 13.9% and 39.7% in the codoped TiO2 nanoparticles, respectively, and were 13.7% and 40.5% in the nanotubes, respectively. Thus, the band gaps of the nanoparticles and nanotubes were narrowed with respect to pure TiO2 and indirect band gaps were introduced and so the light absorption edges were respectively extended to regions of visible light and infrared light. The crystalline nanotubes showed great photodegradation efficiency to methyl orange. The present article discusses some important patents related to TiO2 photocatalysts.