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In the last 10 years, there has been a great increase in synthesis, characterization, and application of innovative porous materials (for example, MCM-41) for catalysis, separation, and sensors. These nanoporous materials normally have pore dimensions of 1–50 nm.
It is more difficult to design, synthesize, and modify nanoporous materials than the synthesis of dense materials. New approaches and methods are continuously being developed for the synthesis and structured customization of nanoporous materials—fueled both by developments in materials science, for example, the synthesis of porous inorganic materials using micellar templates and the discovery of carbon nanotubes, and by industry requirements.
Applications of Nanoporous Materials
Nanoporous materials are extensively used as catalyst supports, adsorbents, and membrane materials; and potential applications include the use of well-ordered nanoporous materials as templates for the manufacture of “nanowires”—electrically conducting wires with a diameter of few nanometers. With growing environmental problems across the globe, porous materials have become more crucial and valuable for the separation of polluting species, recovery of beneficial species, sensors, and catalysis.
Background and Properties of Nanofibers
Nanofibers are hollow and solid carbon fibers having lengths of the order of a few microns and widths ranging from a few tens of nanometers to about 200 nm. These materials have sometimes been called nanotubes. However, they do not possess the cylindrical chicken wire structure of MWNTs and SWNTs; rather, they comprise a mixture of forms of carbon, from graphite layers stacked at different angles to amorphous carbon.
Applications of Nanofiber Materials
Nanofibers are used in a range of fields, such as protective clothing, filtration, biomedical applications like wound dressing and drug delivery systems, application of pesticides to plants, light sails and mirrors used in space, design of solar sails, as well as for structural elements in reinforced composites and in artificial organs.
Background and Properties of Nanowires
Semiconductor nanowires are one-dimensional structures that have exclusive optical and electrical properties. These nanowires are used as fundamental components in nanoscale devices. Their low dimensionality implies that they display quantum confinement effects. For instance, reducing the diameter of the wire boosts its band gap than that of the bulk material.
Applications of Nanowire Materials
Nanowires are used in electronic devices such as sensors, field-effect transistors, light-emitting diodes, and detectors. It is expected that more complex devices will be developed soon, which require new and enhanced methods of growing such wires.