1/18/2011

INTRODUCTION

Recent advances in science, technology and engineering has propelled nanotechnology to the forefront of research and development. It is deemed to be the solution to many problems that seem unsolvable only decades ago, with promises of almost miraculous results and achievements. Nanotechnology, by definition, is the manipulation of matter at the atomic scale (at 10-9 m, or one billionth of a meter). Materials, made up of a collection of atoms and molecules, will be a natural conduit of nanotechnology. The physical, chemical, electrical, optical and magnetic properties of nanomaterials differ from its bulk counterpart on many aspects, sometimes radically.  It is also theorized by some quarters that advances in nanomaterial will lead to an overall technological revolution, from quantum computing, to drug delivery  and sensors, to name a few.
Due to their dimensionality, nanomaterials are very refined version of their bulk counterparts; therefore, unique processing methods are required for their synthesis. Processing methods are generally divided into two major category, the top-down approach, where a bulk material is broken down chemically or mechanically until it reaches nanosize, or the bottom-up approach, where the precursor materials starts from a few strands of molecules or atoms, and it is mechanically or chemically induced to grow into the appropriate size. The choice of processing methods depends on the required properties and sizes of the final product, and the susceptibility of the material itself. The top-down/bottom- up approach covers many operational conditions and environments such as gas, liquid, supercritical fluids, or vacuum.
The nature of nanomaterials makes it difficult for conventional characterization tools to correctly define or show them. Some characterization limitations include low resolutions of the microscopes, the inability of certain characterization agents (neutron, laser) to interact with nanoparticles, and the ineffectiveness/ inconclusive results of direct testing methods (nanomaterials need to be diluted or dispersed before testing). To address this problem, various characterization methods and tools have either been modified, or new ones are being developed, in order to assist researchers in their work.

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