Recent Patents on Materials Science - Volume 4, Issue 1, 2011

This review covers patents that have been published recently on materials that can be incorporated into garments to provide protection from toxic chemicals. Toxic chemicals are defined as substances that can either kill or seriously incapacitate people due to the physiological effects that they have. The review specifically concentrates on semipermeable membranes i.e. those that will act as a barrier to toxic materials but are permeable to water vapour. These breathable membranes offer a lower physiological burden than completely impermeable barrier films since they will allow for significant amounts of water vapour to escape through the protective clothing. These membranes, that in this review are defined as those that possess water vapour permeabilities in excess of 400g m-2 day-1, can be divided into porous and non-porous (hydrophilic) systems. In addition, recent advances in responsive (adaptive) membranes that can switch between permeable and non-permeable modes are also discussed.

Nanocomposite optical materials with high refractive index (RI) have been one of the most attractive issues due to their good optical property that can be used in many fields. The method for preparing high RI nanocomposites is to incorporate high RI inorganic nano-building blocks, for example, metal oxides and metal chalcogenide semiconductor nanoparticles into polymer matrices. The general design requirements and synthetic methods of these high RI nanocomposites are discussed in this review. We classify the synthetic methods into two parts: in situ particle generation method and ex situ particle generation method, and all the methods are reviewed. Some optical applications on antireflection coatings, volume holographic recording materials, high RI LED encapsulant materials, photonic band gap materials and other applications are also reviewed. The relevant patents are discussed in this article.

Different resonances can be supported by thin-film coated optical waveguides depending on the electrical properties of the coating material. One case occurs when the real part of the thin-film permittivity is negative and higher in magnitude than both its own imaginary part and the permittivity of the material surrounding the thin-film. This case is known as surface plasmon resonance (SPR). Other case occurs when the real part of the thin-film permittivity is positive and higher in magnitude than both its own imaginary part and the permittivity of the material surrounding the thin-film. This case is known as lossy mode resonance (LMR). These phenomena have originated many patents, which have been exploited within the last decades originating many applications. Among them, the fabrication of highly versatile sensing platforms, capable of detecting the substance in contact with the coating by monitoring the refractive index variations of the external medium has been one of the leading topics. The intrinsic properties of the materials used to fabricate the thin-films are essential to determine the final properties of these devices. This permits to tune the sensitivity by adjusting the properties of the materials in order to obtain highly sensitive devices with many different applications in the detection of biological and chemical species. In this article, we review different patents, which address these phenomena by using different optical waveguide configurations and coating materials in order to obtain more sensitive, accurate, portable and easy to use devices.

For the last decades, numerous researches and patents are focused on developing novel refining processes of low-cost silicon. In this paper, patents that reveal different refining methods including chemical routes, metallurgical routes and other promising routes are reviewed respectively, and the detailed processes together with their pros and cons are demonstrated according to their basic principles. Based on different processes used for silicon production, the corresponding techniques of fabricating silicon ingots and solar cells are also introduced.

Shear thickening fluids (STFs) have been studied extensively, and an enormous number of patents have been generated due to their potential for commercial applications. STFs draw continued attention as they are considered possible candidate materials for liquid body armour and sporting protective clothing because of their unique properties. This paper presents a review of the “state of the art” STF technology. The ingredient materials, fabrication methods and basic models which describe STF behaviors are discussed briefly. An outline of the patenting activities in the field of STF materials, including the effects of the different particles and their volume fraction in the suspensions on the critical shear rate of shear thickening is presented. Most of the specific patent applications, particularly in body armour, as well as other industrial applications, such as smart structures, and devices with adaptive stiffness and damping, are also summarized. Recent advances, including the effects of particle surface properties, relationship to carrier fluids, electric or magnetic fields applied on the transition of STFs are included in the review. The possibilities of wider applications or designs depend upon a deeper understanding of STFs, as well as the potential of novel STFs to provide protection applications are an impetus for future research.

Laser irradiation, pulse laser deposition and various epitaxial technologies are used for manufacturing novel micro(nano)electronic devices. IR-detectors are of special interest, in particular, their stable functionality under environmental effects seem to be important. None of the optoelectronic active elements operates out of its environment, i.e. we have to consider the unavoidable effect of atmospheric oxygen on all investigated characteristics. Inorganic solids with various band gaps are usually used in industry as optical materials. Many metallic oxides have wide band gaps, because of the significant contribution of the ionic character of the chemical bonds between metallic cations and oxide ions. However, their application for the design of different active elements for optoelectronics requires more detailed information concerning the formation and properties of the corresponding compound. This review discusses this problem and the patents concerning the semiconductor production and assembly using thin film technology.

Recent patents on newly developed composites show that the application of fibres can be used to enhance the structural integrity of polymers. In this work, the scratch behaviour of E-glass fibre-reinforced polyester composites is investigated. The composites are prepared for different fibre orientations, longitudinal, transverse and random. The scratch force is lower for polyester composites with longitudinal orientated fibres compared to transversely aligned orientation. The introduction of glass fibres increases the scratch hardness of polyester.

Hydroxyapatite (HA) is the main mineral component of bone tissue, representing ca. 69 vol% in bone and up to 98 vol% in dental enamel. Its chemical composition close to the mineral phase of bone is the origin of its excellent biocompatibility to tissue bone. Hydroxyapatite has been applied in orthopaedics as block implants, porous, granules and coating material, either dense or porous. However, the application is restricted to non-load bearing application due to its brittleness and low toughness and flexural strength. With this, the development of bioactive dense HA is necessary as it has promising potential in application of load bearing bone implant. Few efforts have been made in developing many methods to produce dense HA. Some of the methods have been combined to prepare dense HA with improved properties. This paper will be discussing the recent progress on efforts which have been done in improving mechanical properties of hydroxyapatite-based dense type biomaterials for load bearing bone substitutes applications. Some recent patents related to dense calcium phosphate are also reviewed.

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.