This award provides partial support for an effort addressing the manipulation of matter on the nanoscale to form functional nanostructures. New methods and tools will be developed and used to: (i) study a new type of mechanochemistry were carbon nanotubes are mechanically strained to create very specific atom locations for chemical reaction (nanostressing stage); (ii) controllably shape surfaces, manipulate nanotubes and build structures with the AFM probe used in a new, unconventional way; (iii) dispense gas and liquid molecules (the latter in volumes down to 100 nm3) with sub-nm positional control (nanotube pipet); (iv) achieve spatiotemporal control over a new class of charged or magnetic particles using finely controlled electric fields or magnetic field gradients (designer particles).
Development of new tools and methods for nanoscale manipulation will be centered around carbon nanotubes (NT). Unique features of NT's as potential building blocks for nanotechnology include: unique size; the presence of a hollow core; unusual mechanical properties; possibilities for mechanically activated chemistry. Tools and methods which will be developed in this study will be essential for achieving one of the long term objectives of the proposed effort - turning NT's into components in functional nanostructures and as tools for building functional nanostructures.
A piezoelectric nanostressing stage will be built and used to apply mechanical stress to NT's and mechanically activate chemical reactions by straining carbon-carbon bonds. Site-specificity of such mechanically sensitized reactions, which are expected to occur in kinked regions of nanotubes, is very desirable for potential applications of NT's in nanotechnology. The nanostressing stage will also be used to elucidate the mechanical behavior of various types of NT's and of very thin graphite sheets (potentially as thin as a single atomic layer).
Tapping mode AFM, which was originally developed to minimize the interactions between the probe and the surface, will be used in a new and unconventional way to manipulate (objects on) surfaces and then image them with high resolution. Operations such as micromachining, nanohammering, and pushing objects on surfaces will be achieved by controlled increase of tip-surface interactions. High-resolution imaging after manipulation will be possible owing to our recent discovery that AFM probes can be resharpened by mechanical deposition of metal grains at the tip. New AFM methods and tools developed at Washington University and also at Zyvex will be applied to manipulation of NT's on surfaces (both at ambient conditions and under liquids) and to study the new mechanochemistry of NT's.
A nanotube pipet, capable of delivering volumes of liquids as small as several tens to a hundred nm3 (note that 1 femtoliter of water is 1 cubic micron, and that 100 nm3 contains 3000 molecules of H2O) will be built and used for fundamental studies of living cells and to construct nanostructures on surfaces. It will be capable of delivering gases, such as organometallics, which could be pyrolyzed on a surface as a means of writing nanoscale metal features, and of delivering very small volumes of biomolecules to cells. %%% ***
