Physics · Ch 11 — Recent Developments in Physics
Nano in laboratories
Nano in laboratories
Laboratory-made nanostructures deliberately mimic nature's own nanostructures, but manufacturing objects this small requires specialised methods. There are two general strategies for synthesising nanomaterials:
Top-down approach. Nanomaterials are made by breaking down larger, bulk solids into nano-sized pieces. Example techniques: ball milling, sol-gel processing, lithography. Conceptually this starts from bulk particles and works down through powder and clusters toward nanoparticles.
Bottom-up approach. Nanomaterials are made by assembling individual atoms or molecules together, selectively adding atoms to build up a structure. Example techniques: plasma etching, chemical vapour deposition. Conceptually this starts from individual atoms and works up through clusters toward nanoparticles -- the opposite direction from the top-down approach, but converging on the same size range. …
What this figure shows. A flowchart branches 'Synthesis of nanoparticles' into a Top-Down Approach (nanomaterials made by breaking down bulk solids into nano sizes, e.g. ball milling, sol-gel, lithography) and a Bottom-Up Approach (nanomaterials made by assembling atoms/molecules together, selectively adding atoms to build structures, e.g. plasma etching and chemical vapour deposition). A second panel shows the same two approaches converging on the same size range from opposite ends of a scale running Bulk particles -> Powder -> Clusters -> Atoms, both …