Amorphous nanoscale particles

Materials for sintering and melting are plastics, metals, or ceramics. Plastics may be unfilled or filled with glass or aluminum spheres or egg-shaped geometries to improve properties like durability and thermal resistance. Also nanoscale particles are used. Unfilled plastics are mostly commodities like semicrystalline polyamides from the PAl 1 or PA12 type or amorphous plastics like polystyrene (PS). Engineering plastics like PEEK are available. 

Therefore, the ideal solution in this field would he the use of solid plasticisers , namely of solid additives which would promote amorphicity at ambient temperature without affecting the mechanical and the interfacial properties of the electrolyte. A result that approaches this ideal condition has been obtained by dispersing selected ceramic powders, such as Ti02, AI2O3 and Si02, at the nanoscale particle size, in the PEO-LiX matrix [35-41]. The conductivity behaviour of a selected example of these nanocomposite polymer electrolytes is shown in Figure 7.5. 

In a mixture of water and methanol, a rapidly mixed reaction still produces mainly broken capsulelike structures. In isopropanol, both the monomer and the oxidant are soluble, therefore, no capsule-like structures are observed but rod-like nanostructures start to appear with large amounts of amorphous materials. Rapidly mixed reactions of pyrrole polymerization were carried out in water, methanol, and isopropanol. Large polypyrrole particles (micron size) were obtained in water, while smaller particles ( -150 nm) were obtained in methanol. In isopropanol, the product disperses very well and glomerates of tiny fibril structures (<30 nm) were found in the product This indicates that further tuning of the solvent-polypyrrole-dopant interactions, reveal well-defined nanoscale morpholr cal units for polypyrrole. 

Inspired by the improved performance of nanoscale-sized silicon particles over bulk silicon particles, many groups have tested silicon thin hlms deposited on metallic substrates (e.g., copper or nickel), in which the thin-hlm silicon contains nanometer-sized silicon features. In general, thin-hlm silicon anodes can be classi-hed into nanocrystahine thin-hlm anodes and amorphous thin-hlm anodes. Graetz et al. [71] prepared nanocrystahine silicon thin-hlm anodes using PVD. These anodes exhibited specihc capacities of approximately 1,100 mAhg with a 50% capacity retention after 50 cycles. The improved electrochemical performance of the thin-hlm anode was linked to good adhesion between deposited silicon particles and the substrate current collector. 

Al-based amorphous alloys containing nanoscale Al particles (Y.H. Kim et al. 

The method produces well-mixed amorphous materials, whose crystallinity can be improved by annealing. Diffusion of species is not the determining step, and hence lower temperatures and shorter times are required than with the ceramic method, thus permitting as well preparation of metastable phases. Additionally, small particles in the nanoscale can be prepared. As a disadvantage, the method is experimentally complex and the starting alkoxides can be expensive. 

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