Nanomaterials composites nanocomposites

Niihara K (2001) Nanomaterials and Nanocomposites with Multifunctionality. Paper presented at 25th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures. Am Ceram Soc, Cocoa Beach, Fl... 

Nanomaterials and nanocomposites have always existed in nature and have been used for centuries. However, it is only recently that characterization and control of structure at nanoscale have drawn intense interest for research and these materials start to represent new and exciting fields in material science. A nanocomposite is defined as a composite material where at least one of the dimensions of one of its constituents is on the nanometer size scale. In other words, nanocomposites can be considered as solid structures with nanometer-scale dimensional repeat distances between the different phases that constitute the structure. These materials typically consist of an inorganic (host) solid containing and an organic component or vice versa. They can consist of two or more inorganic/organic phases in some combinational form that at least one of the phases or features is in the nanosize. 

ID nanomaterial composites - One dimension of the nanomaterial is on the nanometer scale. Examples include thin films, sheets, and platelets. Polymerlayered cmstal nanocomposites fall into this category. 

There is currently considerable interest in processing polymeric composite materials filled with nanosized rigid particles. This class of material called "nanocomposites" describes two-phase materials where one of the phases has at least one dimension lower than 100 nm [13]. Because the building blocks of nanocomposites are of nanoscale, they have an enormous interface area. Due to this there are a lot of interfaces between two intermixed phases compared to usual microcomposites. In addition to this, the mean distance between the particles is also smaller due to their small size which favors filler-filler interactions [14]. Nanomaterials not only include metallic, bimetallic and metal oxide but also polymeric nanoparticles as well as advanced materials like carbon nanotubes and dendrimers. However considering environmetal hazards, research has been focused on various means which form the basis of green nanotechnology. 

Nanocomposites in which one of constituent phases has at least one dimension smaller than 100 run have recently attracted much attention as perspective functional materials of broad spectrum of applications. The growing interest to these novel systems is quite understandable since the bulk behavior of materials can be dramatically altered by controlling their cluster nanostructures, and this control can lead to greatly improved performance. Besides, the characteristics of nanomaterials could be purposely tuned not only by the variation of the chemical composition of the clusters but also by variation of their size and size distribution. 

The chemical-physical properties of nanocomposite and membrane finds unique place in sensor application due to combinational properties. The basic use of nanocomposite is to the products, which show many folds of improvement on the physical and mechanical properties or on the processing properties upon addition of very minute quantity of nanomaterials [99], Nanoscale particles not only enhance the mechanical properties but also have wide potential in the field of electronic, magnetic, optical, and chemical field. The polymer nanocomposites provide improvement over other known composites in thermal, mechanical, electrical, and even air barrier properties [64-70], Formulation of nanocomposite membranes with suitable polymer, suitable nanoparticles, and the processing technology of the nanocomposite are critical to success factor to dominate the gas sensor product in the market. 

Polymeric nanocomposites are an important class of new emerging nanomaterials that exhibits remarkable improvanents of material properties compared with conventional micro- and macrocomposite materials. The small dimension of the filler particles and, accordingly, large surface of the phase separation give the final product characteristics, which considerably exceed traditional ones at minimal filler concentration (Mikitaev et al. 2008). The formation of the polymeric nanocomposite may be represented as the process of filling of the free space in disperse phase with polymer in the form of melt or solution or with monomer followed by its in situ polymerization by chemical or radiation influence on the formed composite structure. The scheme of the polymeric nanocomposite synthesis under radiation is shown in Figure 18.5. 

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