What is top-down and bottom-up approach in nanotechnology?
The top-down approach is a process of miniaturizing or breaking down bulk materials (macro-crystalline) structures while retaining the original integrity. The bottom-up approach involves building of nanomaterials from the atomic scale (assembling materials from atoms/molecules).
There are two general approaches for the synthesis of nanomaterials as shown in Figure 2: a) Top- down approach b) Bottom–up approach. Top-down approach involves the breaking down of the bulk material into nanosized structures or particles.
Bottom-up, or self-assembly, approaches to nanofabrication use chemical or physical forces operating at the nanoscale to assemble basic units into larger structures. As component size decreases in nanofabrication, bottom-up approaches provide an increasingly important complement to top-down techniques.
Integrated circuit fabrication is an example for top down nanotechnology. Now it has been grown to the level of fabricating nano electromechanical systems (NEMS) where tiny mechanical components such as levers, springs and fluid channels along with electronic circuits are embedded to a tiny chip.
The top-down approach to management is when company-wide decisions are made solely by leadership at the top, while the bottom-up approach gives all teams a voice in these types of decisions. Below, we cover the details, pros, and cons of top-down vs. bottom-up management.
Which of the following is an example of bottom-up approach for the preparation of nanomaterials? Explanation: Dip pen nanolithography is an example of bottom-down approach for the preparation of nanomaterials. All the other options are the example of top-down approach.
Several methods are used to fabricate nanostructures using the top-down approach such as photolithography, scanning lithography, laser machining, soft lithography, nanocontact printing, nanosphere lithography, colloidal lithography, scanning probe lithography, ion implantation, diffusion, deposition.
In general, bottom-up approach is meant by synthesis of nanoparticles by means of chemical reactions among the atoms/ions/molecules (Figure 1a). Whereas top-down involves the mechanical methods to crush/breaking of bulk into several parts to form nanoparticles (Figure 1b).
Which of the following is an example of Bottom Up approach? Explanation: Colloidal dispersion is an example of bottom up approach in the synthesis of Nano particles. Attrition, milling and etching are typical top down methods.
A "top-down" approach is where an executive decision maker or other top person makes the decisions of how something should be done. This approach is disseminated under their authority to lower levels in the hierarchy, who are, to a greater or lesser extent, bound by them.
What is the different between bottom up and top down approach to fabricate nanomaterials?
In general, bottom-up approach is meant by synthesis of nanoparticles by means of chemical reactions among the atoms/ions/molecules (Figure 1a). Whereas top-down involves the mechanical methods to crush/breaking of bulk into several parts to form nanoparticles (Figure 1b).
Nanotechnology refers to the branch of science and engineering devoted to designing, producing, and using structures, devices, and systems by manipulating atoms and molecules at nanoscale, i.e. having one or more dimensions of the order of 100 nanometres (100 millionth of a millimetre) or less.
Characteristics of Nanotechnology
Nanotechnology deals with putting things together atom by atom and with structures so small they are invisible to the naked eye. It provides the ability to create materials, devices and systems with fundamentally new functions and properties. The promise of nanotechnology is enormous.
Nanotechnology is a broad name given to a wide range of technologies and materials that create, manipulate, or use particles that have one thing in common - their size. Nanotechnology (or nanoscience) involves materials that are extremely small and have dimensions roughly between 1 and 100 nanometres (nm).
