A Matter of Size Triennial Review of the National Nanotechnology Initiative (2006) / Chapter Skim
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5 Molecular Self-Assembly
5 Molecular Self-Assembly
Pages 99-110
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From page 99... ...
5 Molecular Self-Assembly T he National Research Council Committee to Review the National Nano technology Initiative was asked to "determine the technical feasibility of molecular self-assembly for the manufacture of materials and devices at the molecular scale."1 The committee convened a workshop of experts in February 2005 to examine the technical information and discuss the issues. With input from the participants, the committee parsed this task into two parts: to consider the technical feasibility of self-assembly first, for the manufacture of materials, and second, for the manufacture of devices.
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From page 100... ...
00 A M A t t e r o fSi z e WHAT IS SELF-ASSEMBLY? In the broadest sense, self-assembly describes the natural tendency of physi cal systems to exchange energy with their surroundings and assume patterns or structures of reduced free energy.
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From page 101... ...
Mo l e c u l A rSe l f- AS S e M B l y 0 for the technologist is to find just the right variation of process conditions -- for example, the changes in temperature or the addition of impurities -- that result in the desired material properties. Therefore, molecular self-assembly is certainly feasible for the manufacture of materials.
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From page 102... ...
0 A M A t t e r o fSi z e Kinetic constraints on the possible motions of constituents can greatly reduce the error rate in the assembly of constituent parts. Error-correction processes, such as sorting, refining, and purification, can provide a supply of good subcomponents for the next stage in a hierarchical self-assembly.
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From page 103... ...
Mo l e c u l A rSe l f- AS S e M B l y 0 as narrow as 90 nanometers. Certain critical features, such as the transistor gate length, can be even smaller.
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From page 104... ...
0 A M A t t e r o fSi z e self-assembly. Only the selective removal of single hydrogen atoms embodies the top-down concept of machining.
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From page 105... ...
Perhaps the simplest example is the direct substitution of nonbiological organic or inorganic chemistries for bioorganic chemistries. Examples include bacteria grown in extreme environments and enzymes that catalyze reactions at high pressures and temperatures found outside the normal range of conditions for life processes.
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From page 106... ...
0 A M A t t e r o fSi z e composites. For example, nanoporous materials can be specifically tailored to accommodate individual protein catalysts.
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From page 107... ...
To bring this field forward, meaningful connections are needed between the relevant scientific communities. Examples include: · Delineating desirable research directions not already being pursued by the biochemistry community; · Defining and focusing on some basic experimental steps that are critical to advancing long-term goals; and · Outlining some "proof-of-principle" studies that, if successful, would provide knowledge or engineering demonstrations of key principles or components with immediate value.
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From page 108... ...
2003. 21st Century Nanotechnology Research and Devel opment Act.
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