Nanocomposites, a high performance material exhibit unusual property combinations and unique design possibilities. With an estimated annual growth rate of about 25% and fastest demand to be in engineering plastics and elastomers, their potential is so striking that they are useful in several areas ranging from packaging to biomedical applications. In this unified overview the three types of matrix nanocomposites are presented underlining the need for these materials, their processing methods and some recent results on structure, properties and potential applications, perspectives including need for such materials in future space mission and other interesting applications together with market and safety aspects. Possible uses of natural materials such as clay based minerals, chrysotile and lignocellulosic fibers are highlighted. Being environmentally friendly, applications of nanocomposites offer new technology and business opportunities for several sectors of the aerospace, automotive, electronics and biotechnology industries.

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Nanocomposites: synthesis, structure, properties and new application opportunities

Humidity measurement is one of the most significant issues in various areas of applications such as instrumentation, automated systems, agriculture, climatology and GIS. Numerous sorts of humidity sensors fabricated and developed for industrial and laboratory applications are reviewed and presented in this article. The survey frequently concentrates on the RH sensors based upon their organic and inorganic functional materials, e.g., porous ceramics (semiconductors), polymers, ceramic/polymer and electrolytes, as well as conduction mechanism and fabrication technologies. A significant aim of this review is to provide a distinct categorization pursuant to state of the art humidity sensor types, principles of work, sensing substances, transduction mechanisms, and production technologies. Furthermore, performance characteristics of the different humidity sensors such as electrical and statistical data will be detailed and gives an added value to the report. By comparison of overall prospects of the sensors it was revealed that there are still drawbacks as to efficiency of sensing elements and conduction values. The flexibility offered by thick film and thin film processes either in the preparation of materials or in the choice of shape and size of the sensor structure provides advantages over other technologies. These ceramic sensors show faster response than other types.

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Humidity Sensors Principle, Mechanism, and Fabrication Technologies: A Comprehensive Review

Titanium Dioxide Nanomaterials for Sensor Applications

Mechanically alloyed nanocomposites

Perovskite-type oxides are a class of compounds with the general formula ABO 3 . They are a very important family of materials and exhibit properties suitable for numerous applications. In this review, the preparation, characterization, and application of selected perovskite oxides such as SrTiO 3 , KTaO 3 , NaTaO 3 , KNbO 3 , and NaNbO 3 in photocatalysis are described. In addition, various strategies for enhancing their photocatalytic activities are discussed, including doping with metals and nonmetals (Cr, Ni, Mn, Pb, Bi, N, Br, S, C, and F), modification with noble metal (Au, Ag, Pt, Pd, Ph, Ru) nanoparticles, and doping with rare earth elements (La). Moreover, the review summarizes the influence of different morphologies and surface properties on the photoactivity of the materials.

Selected perovskite oxides: Characterization, preparation and photocatalytic properties—A review

Nanostructured Al-doped ZnO(AZ):TiO2 films are prepared using a sol–gel process and the humidity sensitive properties of the films are investigated. The films possess nanostructure. Nanostructured-bilayered TiO 2/AZ film exhibits improved linearity with narrow hysteresis loop in the resistance variation for relative humidity than single layered film. The resistance of the bilayered TiO 2/AZ film changes by nearly three orders of magnitude during the relative humidity variation of 30–90%. The humidity sensitive properties in the nanostructured AZ:TiO2 films are discussed. © 2003 Elsevier B.V. All rights reserved.

Humidity sensitive properties of nanostructured Al-doped ZnO:TiO2 thin films

Fabrication and magnetic properties of Al2O3/Co nanocomposites

Microstructural characterization of Al2O3/AISI 8650 steel joint brazed with Ag–Cu–Sn–Zr alloy

Nanostructured-bilayered potassium tantalate (KT): titania (TiO 2) films are prepared by the sol–gel process, and the humidity sensing behaviors of the films are investigated. The films possess nanosized grains and nanoporous structure. Bilayered KT/TiO 2 and TiO2/KT films exhibit improved linearity with narrow hysteresis loop in the resistance variation for relative humidity compared to monolayered TiO 2 and KT films. The bilayered KT/TiO 2 and TiO2/KT films show over three orders of change in the resistance during the relative humidity variation from 20 to 90%. The humidity sensing properties in the nanostructured KT: TiO2 films are discussed. © 2004 Elsevier B.V. All rights reserved.

Jun-Gyu Kim

Papers

Humidity sensitive properties of nanostructured Al-doped ZnO:TiO2 thin films

Fabrication and magnetic properties of Al2O3/Co nanocomposites

Microstructural characterization of Al2O3/AISI 8650 steel joint brazed with Ag–Cu–Sn–Zr alloy

Preparation and humidity sensing behaviors of nanostructured potassium tantalate: titania films

Particle size distribution and GMR in Co46Al19O35 granular thin films by annealing