TABLE OF CONTENTS Examples of self-assembling materials include colloidal crystal arrays with mesoscale (50 500 nm) lattice constants that form optical diffraction gratings, and thus change color as the array swells in response to heat or chemical changes. In the case of a hydrogel with an attached side group that has molecular recognition capability, this is a chemical sensor. Self-assembling colloidal suspensions have been used to form a light-emitting diode (nanoscale), a porous metal array (by deposition followed by removal of the colloidal substrate), and a molecular computer switch.
The DNA-based self-assembly mentioned above (Mirkin, 2000 [106]) was achieved by attaching non-linking DNA strands to metal nanoparticles and adding a linking agent to form a DNA lattice. This can be turned into a biosensor or a nanolithography technique for biomolecules.
Development of self-assembly methods could ultimately provide a challenge to topdown lithography approaches and molecular manufacturing approaches. As a result, it could define the next manufacturing methodology at some time beyond 2015. For example, will self-assembly methods trump lithography (the miracle technology of the semiconductor revolution) over the next decade or two?
