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Modern Devices: Chapter 8 – Materials Science

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1 Modern Devices: Chapter 8 – Materials Science
Modern Devices: The Simple Physics of Sophisticated Technology Copyright © John Wiley and Sons, Inc. Chapter 8 – Materials Science Invaluable high-tech contributions Modern Devices: The Simple Physics of Sophisticated Technology by Charles L. Joseph and Santiago Bernal

2 The Importance of Materials Science
Modern Devices: The Simple Physics of Sophisticated Technology Copyright © John Wiley and Sons, Inc. Materials science is really a cross-disciplinary applied-physics field, essential to numerous technologies and the ongoing improvement of many modern devices. The impact of material scientists to modern devices has largely been subsumed in various topics throughout this book. Macroscopically, materials with new properties, ranging from super hardness to time-dependent or environmental-dependent deformation, are being developed. New polymers, composite materials, and functionally and graded materials are other examples having novel bulk properties. On the microscopic scale, material scientists are at the forefront of growing new nanomaterials, wide-band-gap semiconductors, and thin films, among others. Some materials are being created that are capable of molecular self assembly. One of the most promising developments is the ability to synthesize materials and structures that mimic traits found in living creatures, a field of study known as bio mimicry. The Importance of Materials Science to Modern Devices Source: DARPA Outreach, US Government Stent Source: Div. of Biology, Chemistry, & Materials Science, FDA, US Gov.

3 The use of composite materials
Modern Devices: The Simple Physics of Sophisticated Technology Copyright © John Wiley and Sons, Inc. Composite materials, also known as composites, are materials made of two or more constituent materials, resulting in an end product that has significantly different physical or chemical properties from any of its component substances. For example, carbon fibers reinforced with an epoxy polymer are used in aircraft, multicrew racing sailboats, stratospheric balloon gondolas, and spacecraft. These carbon-fiber-reinforced polymers (CFRPs) are much stronger while being significantly lighter than any metal alloy, allowing strong but lightweight structures to be built. Common composites: Carbon-fiber-reinforced polymers Fiberglass Plywood Reinforced concrete The use of composite materials B2 Stealth Bomber US Air Force Titanium (Ti-55A) Carbon Fiber RP Aluminum 2024

4 Thin-Film Multilayers
Modern Devices: The Simple Physics of Sophisticated Technology Copyright © John Wiley and Sons, Inc. Thin-Film Multilayers Materials scientists continue make important improvements to thin-film development and to epitaxial techniques, including homoeptiaxy, heteroepitaxy, heterotopotaxy, and pendeo-epitaxy, for amorphous, crystalline, and polycrystalline materials. wide-band-gap materials in particular have received extensive research investments in recent decades. Multilayer films have been deposited on optics for many decades as interference filters, polarizers, long and short bandpass filters, antireflection coatings, and dichroic filters. However, the sharpness of the wavelength transition between in-band and out-of-band reflectivity/transmission has improved dramatically in the twenty-first century due to more precise control of the deposition processes. Multi-Layer Insulation (MLI) for spacecraft. Source: NASA New multilayer films much thinner than a sheet of paper and enclosing volumes measured in million cubic meters, have dramatically improved near-space stratospheric balloons. Over pressurized and super pressurized balloons enable flight durations of weeks and months instead of 1-3 days. Source of photos: NASA/Columbia National Balloon Facility

5 Modern Devices: The Simple Physics of Sophisticated Technology
Copyright © John Wiley and Sons, Inc. The emerging field of nanotechnology is the manipulation of materials and the fabrication of devices on the nanometer (nm = 10-9 m) scale. In other words, nanotechnology pertains to device structures with sizes of 1 to 100 nm in at least one dimension. (Atoms have diameters of approximately 1 Angstrom [i.e., 0.1 nm], which implies devices can be as small as 10 atoms across in nanotechnology – a natural barrier preventing further miniaturization.) There is a wide range of potential applications for nanotechnology, both militarily and commercially. Important future uses include among others: nanomedicine, nanotoxicology, green nanotechnology, and regulation. Significant future nanomaterials comprise fullerenes, carbon nanotubes, nanoparticles, nanowires, and quantum dots. A single bit (a “1” or a “0”) in a computer, for example, might ultimately be reduced to whether or not a single atom is caged inside a nanotube. Nanotechnology

6 Modern Devices: The Simple Physics of Sophisticated Technology
Copyright © John Wiley and Sons, Inc. An exciting example of nanotechnology is molecular tweezers, having two arms that are capable of latching onto a single molecule. The term was first introduced by Howard Whitlock and popularized by Steven C. Zimmerman in the mid-1980s to early 1990s. Pictured is a crystal structure of molecular tweezers, consisting of two corannulene pincers clasping a C60 fullerene (Buckyball molecule). Nanotechnology Figure 8.1 Molecular tweezers clasping a C60 fullerene. Source: Sygula et al. (2007), J. of Am. Chem. Soc. 2007, vol. 129, 3842, reprinted with permission.


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