-
Asked by anon-199631 to Aryanne on 4 Mar 2019.
Question: How do you make nanoparticles?
- Keywords:
-
Aryanne Finnie answered on 4 Mar 2019:
this is a good question but not an easy answer! Basically what you are trying to do is reduce bulk gold down to the nano state, where it has completely different properties from the usual gold you would usually wear as jewelry! You would usually use chloroauric acid, which contains the gold you are going to reduce, and a reducing agent. You also need a compound that is going to basically keep the gold in this nano-size once you have reduced it down, so it’s going to coat around it and “stabilise” it. This is the short answer as it can get very complicated!
Comments
Sumit commented on :
do you know how big is an gold atom? it is 166 picometre = 0.166 nanometre. now think about a cube. you have 8 corners and 6 edges. You will find 1 gold atom in each corner and at the middle of the edge. so how many gold atoms you need to make one gold cube? 8 +6 = 14; right? Now I ask you to put such gold cubes in all three dimensions. What will happen? Corners and edge golds will share with their neighbours. If we consider this sharing, then 1 gold cube has only 4 gold crystals (8 corner X 1/8 and 6 edge X 1/2 = 1+ 3 =4. (Ask your teacher to help you to understand). Therefore 4 gold atoms make 1 gold crystal. all the atoms do not touch each other, there is always some empty space in the crystal. One gold cube is 0.0679 cubic nanometre (each side of the cube is 0.408 nm, volume of cube V = L 3).
Now what is nano particles? nanopraticles are formed with hundreds to thousands of gold cubes and they look like sphere with diameter between 1-100 nm. Different size gold nano particles have different colours. Now depending on the size of your gold nanoparticles you can fit as many cubes as possible. Now can you calculate how many gold atoms will be present for a 2 nm diameter gold nano particle? ask your teacher for help. Otherwise, I am happy to help you. Isn’t it cool?