Recent Patents on Materials Science - Volume 3, Issue 1, 2010

The aim of the present work is to bring together, in a coherent way, recently-patented technologies in the field of polymer-clay composites, in order to provide scientists and engineers in this area with a quick guide on the most up-todate inventions. It is well known that in recent years polymer-clay composites have received increased attention for their ability to improve polymer properties, including gas barrier, heat deflection temperature, and modulus. An important amount of the patented work in the field of clay-based composites is closely related to the ability of such materials to swell when in contact with water and act either as thickeners or as sealing devices. For this reason a significant number of the clay-related patents that were published during the last decade are oriented towards applications like hydraulic barriers, water purifications systems, toothpastes, shampoos and other cosmetics. Additionally, some novel and rather uncharacteristic applications, such as cholesterol reduction and virus neutralization, are discussed in this work. Although the review cites a few patents that were published more than ten years ago, the primary focus of this work is on the inventions patented in the last decade.

In this review article recent studies about the corrosion and the influence of corrosion on the surface magnetic properties of amorphous and nanocrystalline magnetic ribbons are presented. The studies have been performed in Febased and Co-based amorphous ribbons, because these ribbons are used in different magnetic sensors. In the first case the investigation has been focused on the corrosion, the influence of corrosion in the surface magnetic properties and the influence of the nickel content on the electrochemical behaviour. The results show that in the amorphous samples, when the oxidized layer increases, the surface saturation magnetization decreases. However, in the nanocrystalline samples the surface saturation magnetization does not change significantly. The values of the surface coercive field for the oxidized and non oxidized samples with the same Ni content are practically the same. In the case of Co-based ribbons the study has been focused in the corrosion process and how the corrosion affects the magnetoimpedance response of the ribbons. The results indicate that FeCoCrSiB ribbons show an excellent corrosion stability and high magnetoimpedance response, meanwhile FeCoSiB ribbons show low corrosion resistance but high magnetoimpedance response. The relevant patents discussed in this article cover the areas connected with the application, magnetic behaviour and corrosion of amorphous and nanocrystalline materials.

Organic photovoltaic (OPV) materials demonstrate good capabilities for photon-electricity conversion. Recently, they have attracted extensive attention because of the increased energy consumption of the emerging economies. OPV materials show many advantages including low-cost, light-weight, easy-processing, and good flexibility. OPV materials are usually synthesized from conjugated polymers that have high quantum efficiency, wide absorption spectra, and high carrier mobility. In this review, patents on the mechanism of photovoltaic conversion and the advancement of OPV research are reviewed. In addition, future research directions and possible breakthroughs in this field are addressed.

Recent advances in the applications of ferroelectric polymers are introduced in terms of the recent patents in connection with the ferroelectric polymers. The principal applications of ferroelectric polymers include high dielectric constant materials, high energy density storage materials, high strain and electrostrictive actuators, multilayer actuators, ferroelectric polymer memories, energy harvesting devices and artificial muscles. In the mean time, the compositionstructure- property relation is also introduced in order to better understand the versatile applications of various ferroelectric polymers.

Mesoporous structures are said to be the most important discovery in the field of materials science in 90s. Thanks to their extremely large specific surface area and interconnected channels, these materials show excellent surfacerelated properties well suited for many applications such as catalytic reactions, separation, and recently, gas sensing. As a relatively new field in materials science, mesostructured materials show promising properties in gas sensing applications bringing the advantage of fast response and recovery as well as high degree of stability as compared to commercially available micro-scale materials. This article is a short review of patents on mesoporous materials and their applications in gas sensing technology and integrated chromatography systems.

Chalcogenide semiconductor thin films are reported for the first time as prospective aggressive gases sensors. Results of structural investigations and electric field-induced properties of thin (40-100nm) Bi-containing semiconductor thin films grown on glass substrates by UHV technique are reported. Microstructure and phase composition of the films are examined by transmission electron microscopy (TEM) and electron diffraction methods. Room-temperature currentvoltage dependencies are also studied and possible mechanisms of charge carrier's transport are discussed. Recent patents on thin film-based gas sensors production are also discussed in this paper.

The chemical modification of macromolecules, with the purpose to provide them better properties, is a topic that emerged in mid last century. Further, a little later (sixties in XX century), there were ascertained that the interfacial agents based on polymer chemically modified (or functionalized polymers) appeared as the key in order to optimize multiphase materials in terms of morphology and structure of the interfacial regions between phases. As a consequence, the scientific and technical literature based on this topic, and especially those based on grafted polyolefins, augmented exponentially. Beyond the patent laws and regulations, some major questions related to the limits of the rights protected are still open and constitute a subject of controversial. As a mere example, it can be mentioned, the protection of the equivalent substantial elements of any invention or the content and importance of the state of the art embodied in the technical document, among others. Nevertheless, the huge number of patents published in this scientific-technical field (many sponsored by leader companies from the chemical, clinical, electronic, or automotive industries) is a strong indicator of the importance of the topic. The function of the average person skilled in the art is indeed one of the most key aspects related to the patent literature and the present survey is focused on this point of view. Because of the difficulty to fully well solve the chemical structure of the chemically modified polyolefin, i.e., the number and location of the functionalities grafted onto the polymer, by using the classical finger print structural characterization techniques such as NMR, (s) NMR, FTIR spectroscopy, or x-r diffraction, several scientific questions remain open and explain the huge research efforts devoted to them. As a consequence, patents related to the topic are concerning not only to the chemical modification processes but also to the new properties (and/or uses) of these grafted polyolefins, (i.e., in compounding operations; in purification processes and/or procedures, and so on), and not to the mere protection of the fingerprint (or structure) of the chemically modified polymeric substance.

The patents annotated in this section have been selected from various patent databases. These recent patents are relevant to the articles published in this journal issue, categorized by materials, biomaterials, biological materials, magnetic materials, medical implant materials, nanomaterials, ceramics, plastics, polymers, semi-conductors, coatings, composites, paper, wood, textile, methods design and techniques.