Nanotechnology: How are Nanoscale Products Manufactured?

the traditional way to reduce particle size for a given compound is via roll mill or sheering. however, there is a limit that these mechanical processes can reduce the particle size. Therefere new technology must be developed to reduce the particle size even further.

Im sure there are a few ways out there to reduce the particle size of a compound but the type of process depends purely on the properties of the compound. For example, supercritical CO₂ has been used as a solvent to dissolve compounds then a solid cosolvent is added and finally the solution is passed through a nozzle to allow the CO₂ to evaporate. The cosolvent hinders the compounds ability to clump together, thus leaving behind the compound with smaller particle sizes.

For compounds that are not soluble in supercritical CO₂, an alternative is Supercritical Anti Solvent processes in which a vibrating surface is used. In this process, the particle size is inversely related to the vibrational frequency, therefore the higher the frequency the smaller the particle size.

key phrases: rapid expansion supercritical solution with solid cosolvent

supercritical anti solvent

Nanoscale TiO2 particle can be precipitated out of solution using a sol-gel method

Ti(C4H7O)4 →(H20)→Ti(OH)4 + C4H70H (butanol)

then

Ti(OH)4 →(heat)→TiO2

precursor is expensive but this method seems the most direct to me.

I'd search TiO2 nanoparticles and sol-gel method for details of the synthesis method

Jim Mikulak

This is producing spheres of controllable size - very uniform - the absolute size controlled by the addition of ammonia to the solution and temperature at stirring after mixing.

Particle size is 0.2 to 2 micrometer.

If non spherical particles are ok then take a water soluble nitrate or may be formiat, acetate or salts of the other carbonic acids, mix with water to dilute, spray to form droplets in hot dry air to get immediate evaporation.

Or mix the abovementioned organic titanium with an appropriate solvent, spray and decompose by heat.

I suppose that the tetra ethoxi titanium is more suitable.

All of these are flammble and may be explosive with air!

If you need very fine particles you will need to get some sputtering equipment to do vacuum condensation in 1 to 10 mbar Argon, to catch the particles in a film of non volatile oil to be able to handle this stuff.

Have success

RHABE